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Bioethanol Production From Agricultural and Municipal Wastes
Abstract
Bioethanol, one of the most promising technological advancements of the century, has been widely acclaimed for being produced from diversified origins. Production of bioethanol from food grains (as in Brazil or the United States) is however frequently criticized in the food vs. fuel debate. Several research studies across the globe, investigating the potential use of various renewable resources (such as waste biomass), have resulted in the emergence of second and/or third generation bioethanol processes. This chapter attempts to consolidate various aspects of bioethanol production from solid waste biomass. Waste biomass of lignocellulosic and starch-based origin, such as municipal solid waste, industrial waste (waste paper or coffee residues), livestock manure, and agricultural waste (wood biomass and agricultural crop residues), were reviewed for their potential to produce ethanol. This chapter describes the feedstock prospects, process technologies, and the current research and industrial developments
... Lignocellulosic biomass can be obtained from four major sources: agro-industrial residues, energy crops, woody biomass, and municipal solid wastes [15,25]. The agro-industrial residue is a byproduct of agricultural production or its industrial processing including corn stover, corn cobs, coconut coir, cotton stalks, rice husks, sugar cane bagasse, wheat straw, and rice straw. ...
... Agro-industrial residues are characterized by shortharvest rotation which are consistently available to bioethanol production. Besides, no additional land is needed for their cultivation because the land used for food production is adequate to generate such biomass [12,25]. Energy crops belong to the world's high-yield biomass and include switchgrass, bermudagrass, and miscanthus [26]. ...
... Energy crops belong to the world's high-yield biomass and include switchgrass, bermudagrass, and miscanthus [26]. They are easily cultivated forms of biomass that do not need to be replanted every year and do not require special care and high maintenance to grow [25]. Forestry and its residues include woody biomass and residues from paper mills and timber processing: trimmings, wood chips, sawdust, and barks. ...
The conversion of lignocellulosic biomass into bioethanol remains a challenging process due to the recalcitrant structure of lignocellulose. The presence of the sturdy lignin protective sheath, complex structure, and partial crystallinity of cellulose often reduces the enzymatic susceptibility of lignocellulosic biomass. Therefore, pretreatment is aimed to increase accessibility by improving the physicochemical properties and composition of lignocellulosic biomass. It is the first and the most critical step that needs to be carefully selected and designed to overcome the constraints and improve the overall efficiency of bioethanol production. In recent years, ball milling has been applied as an emerging technique to produce bioethanol from lignocellulosic biomass efficiently and in an environment-friendly manner. Furthermore, ball milling technique coupled with chemical and physicochemical pretreatments has been shown to facilitate lignin removal, reduce cellulose crystallinity, and increase the specific surface area which ultimately improves the digestibility of lignocellulosic biomass. Over the last decade, several reports have been published on the application of ball milling to intensify the pretreatment process. However, a compiled report showing the progress of the technology in bioethanol processing is absent. In this review, a critical analysis and evaluation of published works on ball milling and ball milling–assisted chemical/physicochemical pretreatments are presented. It also addresses the synergistic effects of combining ball milling and chemical/physicochemical treatments to bring desirable characteristics of lignocellulosic biomass that will eventually improve hydrolysis yield and reduce chemical and energy consumption in bioethanol production.
... In recent years, plasma-assisted gasification has offered a sustainable and cleaner technology for WTE-project [30].In several of the neighboring countries of Bangladesh, WTE techniques have been implemented to recover the value of MSW [95]. In India, sophisticated methods of WTE techniques are under development, such as bioethanol from waste [96], gasification [97], LFG [72], etc. However, these techniques have not been successful in evolving into long-term solutions due to a lack of consciousness, funding, and different operational and technical insufficiencies [96]. ...
... In India, sophisticated methods of WTE techniques are under development, such as bioethanol from waste [96], gasification [97], LFG [72], etc. However, these techniques have not been successful in evolving into long-term solutions due to a lack of consciousness, funding, and different operational and technical insufficiencies [96]. The focus on energy production from WTE techniques is increasing daily, and production has been increasing in the last few years [49]. ...
Municipal solid waste (MSW) management has become a major concern for developing countries. The physical and chemical aspects of MSW management and infrastructure need to be analyzed critically to solve the existing socio-economic problem. Currently, MSW production is 2.01 billion tonnes/yr. In developing countries, improper management of MSW poses serious environmental and public health risks. Depending on the socio-economic framework of a country, several MSW management procedures have been established, including landfilling, thermal treatment, and chemical treatment. Most of the MSW produced in underdeveloped and developing countries such as Bangladesh, India, and Pakistan is dumped into open landfills, severely affecting the environment. Waste-to-Energy (WTE) projects based on thermal treatments, e.g., incineration, pyrolysis, and gasification, can be feasible alternatives to conventional technologies. This research has explored a comprehensive method to evaluate MSW characteristics and management strategies from a global and Bangladesh perspective. The benefits, challenges, economic analysis, and comparison of MSW-based WTE projects have been analyzed concisely. Implementing the WTE project in developing countries can reduce unsupervised landfill and greenhouse gas (GHG) emissions. Alternative solutions and innovations have been discussed to overcome the high capital costs and infrastructural deficiencies. By 2050, Bangladesh can establish a total revenue (electricity sales and carbon credit revenue) of USD 751 million per year in Dhaka and Chittagong only. The landfill gas (LFG) recovery, waste recycling. and pyrolysis for energy production, syngas generation, and metal recovery are possible future directions of MSW management. The MSW management scenario in developing countries can be upgraded by improving waste treatment policies and working with government, academicians, and environmentalists together.
... Liquid biofuels have been analysed by (Nair et al., 2016) for bioethanol production, and (Kalyani and Pandey, 2014) present a wider MSW analysis considering biodiesel production as one of the options. The main observations, as summarised in Table 4, are that on the positive side, there are no conflicts in producing such fuels with food security, reducing the GHG, but there can be high costs for building the facilities due to machine import and for plant operation due to the eventual need for importing highly qualified operators. ...
... • High cost for processing and synthesis technology; (Nair et al., 2016) (Kalyani and Pandey, 2014) • Reduction of GHG and climate change. ...
The proper handling of Municipal Solid Waste (MSW) is critical due to its high generation rate and the potential to minimise environmental impacts by simultaneously reducing resource depletion and pollution. MSW utilisation for recycling is important for transforming the linear economy model into a circular one. The current review analyses and categorises MSW to energy technologies into direct and indirect approaches taking the Circular Economy perspective. The direct approach involves incinerating MSW for heat recovery. The indirect approach, including thermochemical and biochemical processes, is more complicated but attractive due to the variety of the valorised products – such as syngas, bio-oil, biochar, digestate, humus. However, consensus on the best MSW treatment approach is yet to be established due to the inconsistency of assessment criteria in the existing studies. In the case of converting MSW to energy (Waste-to-Energy – W2E), its economic indicators, such as capital, compliance, and operation cost, are important criteria when implementations are considered. In the current work, the critical characteristics of technologies for the MSW to energy routes are scrutinised. In addition, the economic characteristics and the role of MSW in the circular bio-economy is also thoroughly evaluated. Methods to advocate the industrial adoption and important assessing aspects of W2E are proposed at the end of the review to address the environmental and resource management issues related to MSW – most notably dealing with the uncertainty in composition and amounts, the energy efficiency and the resource demands of the W2E processing.
... In this case, the alkali pretreatment was carried out as pretreatment technique, but when the organism T. harzianum inoculum was used, the yield gradually increased as the reducing sugar is inversely proportional to the ethanol production increases. Similarly, a large number of microorganisms can be used to improve the production, and it is mostly advised to use this microbe after the hydrolysis technique (Kongkeitkajorn et al. 2020 This is an attractive feedstock as compared to others for bioethanol production, as it is readily available (Nair et al. 2017). Paper sludge mainly contains cellulosic fibers, while paper mill uses different feedstocks. ...
... The feasibility of ethanol is a major problem as it is limited to laboratory use. A model was predicted to obtain the maximum yield (Nair et al. 2017). Critical variables that affect the process were identified and they are optimized in order to improve the yield. ...
One of the most significant challenges in the twenty‐first century is to meet the growing energy demand. Thus, the need for the production of ethanol increased gradually as it is the most widely used biofuel around the globe. In this chapter, various advanced methods and techniques to synthesis bioethanol are discussed. All over the world, research on bioethanol production has grown alongside increasing energy needs, and it has become a research area of great interest to many governments, academic groups, and companies. This liquid biofuel can tackle problems associated with rising crude oil prices, global warming, and diminishing petroleum reserves. Production of bioethanol mitigates the greenhouse gas (GHG) emissions and leads to a sustainable environment. The former technologies mainly depended upon food crops that lead to stress on food prices and also affected food security. Ethanol, which is presently the most common renewable fuel, can be produced biologically from a variety of feedstocks and wastes. Hence, the recent focus has been on other waste products and lignocellulosic materials to produce a third‐ and fourth‐generation bioethanol. This review summarizes the most up to date methods of bioethanol production and various enlightened steps involved in the synthesis. Also, the significant factors affecting it are presented and discussed to meet the industrial demand. Also, different integrated techniques are discussed, which makes the process more efficient.
... This waste consists of organic materials, paper, plastic, glass, and metals collected by municipal authorities. As reported by Nair et al. [36], 1.42 kg/capita/day of MSW are expected to be produced by 2025. Considering the current population numbers, 4 × 10 5 Mt/year of MSW is estimated to be produced in Europe. ...
... Considering the current population numbers, 4 × 10 5 Mt/year of MSW is estimated to be produced in Europe. Organic waste accounts for about 60% of the MSW [36], thus 2 × 10 5 Mt/year of urban organic waste are expected to be available as feedstock for biofuel production in Europe. ...
To make biofuel production feasible from an economic point of view, several studies have investigated the main associated bottlenecks of the whole production process through approaches such as the “cradle to grave” approach or the Life Cycle Assessment (LCA) analysis, being the main constrains the feedstock collection and transport. Whilst several feedstocks are interesting because of their high sugar content, very few of them are available all year around and moreover do not require high transportation’ costs. This work aims to investigate if the “zero miles” concept could bring advantages to biofuel production by decreasing all the associated transport costs on a locally established production platform. In particular, a specific case study applied to the Technical University of Denmark (DTU) campus is used as example to investigate the advantages and feasibility of using the spent coffee grounds generated at the main cafeteria for the production of bioethanol on site, which can be subsequently used to (partially) cover the campus’ energy demands.
... In this facilities, organic fraction can be converted into biogas while inorganic fraction can be converted into solid recovered fuel (SRF) to produce syngas [39]. An integrated gasification system with a fuels synthesis facility can convert syngas to bio-diesel, bio-jet fuel, bio-methanol or bio-ethanol [40]. Fuels from MSW biorefineries can be used in termal power plants, transportation, or in district heating. ...
... Combined heat and power bio-refinery to treat MSW[40]. ...
This chapter/research review is a study of the different waste-toenergy technologies (WTE-Ts) developed to date. This study of the technologies is divided into four groups: biological treatment of waste; thermal treatment of waste; incineration of waste; and landfill gas utilisation. Furthermore, integrated solid waste management systems (ISWM-S) with WTE-T are studied and some worldwide examples are provided.
... In this facilities, organic fraction can be converted into biogas while inorganic fraction can be converted into solid recovered fuel (SRF) to produce syngas [39]. An integrated gasification system with a fuels synthesis facility can convert syngas to bio-diesel, bio-jet fuel, bio-methanol or bio-ethanol [40]. Fuels from MSW biorefineries can be used in termal power plants, transportation, or in district heating. ...
... Combined heat and power bio-refinery to treat MSW[40]. ...
The generation rate of Municipal Solid Waste is expected to increase to 2.2 billion tonnes per year by 2025 worldwide. However, in developing countries, collection, transport and disposing of waste is still challenging while, in developed countries, emerging technologies are used to produce different by-products such as heat, electricity, compost and bio-fuels. This study assesses the different waste-to-energy technologies developed to date. This work is divided into four groups: biological treatment of waste; thermal treatment of waste; landfill gas utilization; and biorefineries. Furthermore, integrated solid waste management systems with waste-to-energy technologies are studied and some worldwide examples are provided.
... When considering paper waste as a lignocellulosic biomass for bioethanol production it is a promising feedstock because of it is highly abundant, costeffective, and have relatively high amount of carbohydrates. It can easily digest without aggressive physical or chemical pretreatments, and, most notably, waste paper for bioethanol production is very efficient (Nair, Lennartsson and Taherzadeh, 2017;Ojewumi et al., 2018). Bioethanol does have the potential to become a future energy crisis solution because it can be used directly in specially constructed engines or as lower blends in compression ignition (CI) engines without requiring any modifications. ...
The demand for more environmentally friendly alternative renewable fuels is growing as fossil fuel resources are depleting significantly. Consequently, bioethanol has attracted interest as a potentially viable fuel. The key steps in second-generation bioethanol production include pretreatment, saccharification, and fermentation. The present study employed simultaneous saccharification and fermentation (SSF) of cellulose through bacterial pathways to generate second-generation bioethanol utilizing corncobs and paper waste as lignocellulosic biomass. Mechanical and chemical pretreatments were applied to both biomasses. Then, two bacterial strains, Bacillus sp. and Norcadiopsis sp., hydrolysed the pretreated biomass and fermented it along with Achromobacter sp., which was isolated and characterized from a previous study. Bioethanol production followed by 72 h of biomass hydrolysis employing Bacillus sp. and Norcadiopsis sp., and then 72 h of fermentation using Achromobacter sp. Using solid phase micro extraction combined with GCMS the ethanol content was quantified. SSF of alkaline pretreated paper waste hydrolysed by Bacillus sp. following the fermentation by Achromobacter sp. showed the maximum ethanol percentage of 0.734±0.154. Alkaline pretreated corncobs hydrolyzed by Norcadiopsis sp. yielded the lowest ethanol percentage of 0.155±0.154. The results of the study revealed that paper waste is the preferred feedstock for generating second-generation bioethanol. To study the possible use of ethanol-diesel blends as an alternative biofuel E2, E5, E7, and E10 blend emulsions were prepared mixing commercially available diesel with ethanol. The evaluated physico-chemical characteristics of the ethanol-diesel emulsions fulfilled the Ceypetco requirements except for the flashpoint revealing that the lower ethanol-diesel blends are a promising alternative to transport fuels. As a result, the current study suggests that second generation bioethanol could be used as a renewable energy source to help alleviate the energy crisis..
... Many pre-treatment technologies have been developed in the last decades and have important effects on downstream procedures, yields, and costs (da Costa Sousa et al., 2009;Nair et al., 2017;Awasthi et al., 2020;Park et al., 2020). Among the pre-treatments, steam explosion unsettles lignocellulosic materials by physical and chemical reactions, allowing a more effective subsequent enzymatic digestion. ...
The production of lignocellulosic ethanol calls for a robust fermentative yeast able to tolerate a wide range of toxic molecules that occur in the pre-treated lignocellulose. The concentration of inhibitors varies according to the composition of the lignocellulosic material and the harshness of the pre-treatment used. It follows that the versatility of the yeast should be considered when selecting a robust strain. This work aimed at the validation of seven natural Saccharomyces cerevisiae strains, previously selected for their industrial fitness, for their application in the production of lignocellulosic bioethanol. Their inhibitor resistance and fermentative performances were compared to those of the benchmark industrial yeast S. cerevisiae Ethanol Red, currently utilized in the second-generation ethanol plants. The yeast strains were characterized for their tolerance using a synthetic inhibitor mixture formulated with increasing concentrations of weak acids and furans, as well as steam-exploded lignocellulosic pre-hydrolysates, generally containing the same inhibitors. The eight non-diluted liquors have been adopted to assess yeast ability to withstand bioethanol industrial conditions. The most tolerant S. cerevisiae Fm17 strain, together with the reference Ethanol Red, was evaluated for fermentative performances in two pre-hydrolysates obtained from cardoon and common reed, chosen for their large inhibitor concentrations. S. cerevisiae Fm17 outperformed the industrial strain Ethanol Red, producing up to 18 and 39 g/L ethanol from cardoon and common reed, respectively, with ethanol yields always higher than those of the benchmark strain. This natural strain exhibits great potential to be used as superior yeast in the lignocellulosic ethanol plants.
... However, 1G has several unsustainability issues bound to the great request of crops subtracted to the food chain and the cultivation of large areas (destined for this purpose) that causes deforestation and decrease of biodiversity [121]. As an alternative, in the "second-generation" technologies (2G), lignocellulosic materials are employed as feedstocks; in this respect, lignocellulose is cheap and immediately available in a large amount [122], but the development of tailored technologies is necessary to exploit more recalcitrant components. For example, both 1G and 2G technologies have to simultaneously maximize production yield and reduce costs and environmental impact; in both cases, exploitation of microbial mechanisms and biocatalysis supports the process. ...
Extremophiles are microorganisms that populate habitats considered inhospitable from an anthropocentric point of view and are able to tolerate harsh conditions such as high temperatures, extreme pHs, high concentrations of salts, toxic organic substances, and/or heavy metals. These microorganisms have been broadly studied in the last 30 years and represent precious sources of biomolecules and bioprocesses for many biotechnological applications; in this context, scientific efforts have been focused on the employment of extremophilic microbes and their metabolic pathways to develop biomonitoring and bioremediation strategies to face environmental pollution, as well as to improve biorefineries for the conversion of biomasses into various chemical compounds. This
review gives an overview on the peculiar metabolic features of certain extremophilic microorganisms, with a main focus on thermophiles, which make them attractive for biotechnological applications in the field of environmental remediation; moreover, it sheds light on updated genetic systems (also those based on the CRISPR-Cas tool), which expand the potentialities of these microorganisms to be genetically manipulated for various biotechnological purposes.
... In recent years, the conversion of fruit and agricultural wastes into high-value-added materials is greatly significant due to the high volume and cheapness of these wastes [1,2]. Pomegranate is one of the most important agricultural products which are used all over the world due to its anti-cancer and antimicrobial properties and also its antioxidants. ...
Due to the high production of pomegranate peel waste in the world, and its good lignocellulosic content, this substance can be a good source for fuel bioethanol production. In this study, the simultaneous saccharification and fermentation (SSF) process was investigated and optimized for bioethanol production from pomegranate peel (PP). After hydrothermal pretreatment on pomegranate peel and separation of pectin and phenolic compounds, the SSF process was performed using cellulase and Saccharomyces cerevisiae. The effect of the four parameters of pH, temperature, solid loading, and enzyme dosage on the bioethanol production in the SSF process was investigated and optimized using the response surface methodology (RSM). Optimal process conditions were determined as follows: pH 5.65, temperature 40.3 °C, solid loading 12.8% w/v, and enzyme dosage 32.3U, under which the maximum amount of ethanol produced was 12.9 g/l. Furthermore, 90.4% of initial sugar was consumed by the yeast during the process, and the yield of ethanol production was 48.5%, which corresponds to 95.09% of the theoretical yield. The trend of changes in ethanol and sugar concentrations during the process time was also studied.
... Likewise, the use of these agricultural residues is quite extensive and highly studied, including the extraction of compounds of pharmaceutical interest (Didaskalou, Buyuktiryaki, Kecili, Fonte, and Szekely, 2017), fertilizers (Lupton, 2017), and fermentable sugars for the production of biofuels (C. Huang, Jeuck, and Yong, 2017;Nair, Lennartsson, and Taherzadeh, 2017). ...
In Colombia, approximately 855 840 tons of arracacha are produced each year. The unsalable post-harvest arracacha root (ArracaciaxanthorrizaBancroft) is not commercialized, mainly due to mechanical damage or small and misshapen roots. In this work, drysamples were characterized and subjected to two treatments: one using thermal hydrolysis, applying saturated steam at pressures of0,1034 MPa, 0,2068 MPa, and 0,4137 MPa; and another one using hydrolysis with sulfuric acid in concentrations between 0,25-2,00M. Then, the cake resulting from the hydrolysis and filtration process was enzymatically hydrolyzed (Liquozyme SC DS, Novozymes)at 1,5, 5 and 10 KNU/g (pH 6, 80◦C, 2 h). Fermentation inhibitors (acetic acid and furfural) were evaluated in the best pretreatment.The results showed that the treatment with sulfuric acid at 1,00 M (2 h) has high yields in reducing sugars added to enzymatichydrolysis. The maximum level of fermentable carbohydrates per gram of dry sample (1,04 g/g) was also reached. Regarding thefermentation inhibitors of the reducing sugar, a higher concentration of acetic acid was found with a lower furfural content. Therefore,arracacha discards are a promising raw material to increase the supply of bioethano
... Keeping such issues about risks associated with first-generation bioethanol, the research focus has been moved towards "second-generation technologies," where the exploitation of non-food-based crops (with no-food parts) and wastes originated from wood or food-based industries represent most plentiful renewable organic constituents in the biosphere (Zucaro et al. 2016;Donato et al. 2019). Therefore, the second-generation bioethanol is derived from "lignocellulosic biomass" which is generated by agricultural practices, wood-based industries, municipal solid wastes, and dedicated energy crops cultivating on trivial lands (Nair et al. 2017). The biomass in form of lignocelluloses represents an economically feasible and renewable/inexhaustible reservoir for the production of eminent fuel in form of "bioethanol" (Donato et al. 2019;Prasad et al. 2019). ...
In the modern world, the attention is raised for the development of newer technologies for the transformation of biological wastes into biofuels as an alternative option of exhaustible petroleum or other sources. The organic parts of agricultural wastes, forest residues, food wastes, and municipal and industrial wastes contain an unlimited source of lignocellulosic biomass which could potentially be used for generating second-generation biofuels such as “bioethanol.” Microorganisms play an important role in all probable steps intended for lignocelluloses hydrolysis. The greener technological approach for green fuel production through application of microorganisms is a sustainable and renewable approach which is carried out in three steps such as (a) hydrolysis of lignin; (b) hydrolysis of cellulose and hemicelluloses; (c) fermentation of glucose to ethanol. The high production of ethanol is the need of the cotemporary world and therefore it becomes necessary to explore different microorganisms having a high potential for ethanol yield. Moreover, introducing metabolic engineering techniques is the current advancement for development of modified microbial cells for enhanced production of ethanol from lignocellulosic biomass. The present chapter focuses on the valorization of lignocelluloses waste through microorganisms and their mechanisms required for bioethanol synthesis from lignocellulosic biomass.
... Some of the drawbacks of incinerating bio-wastes are the resulting toxic SOx dioxin emissions dioxins and generation of ash laden with heavy metals [64]. Moreover, some materials that could act as feedstocks for incineration plants contain nitrogen can potentially be converted to NOx emissions, which would demand sophisticated gas-cleaning equipment [65]. Additionally, bio-wastes have been associated with elevated heavy metal emissions as well as acidification of the flue gases [62,66]. ...
The energy sector contributed to three-fourth of overall global emissions in the past decade. Biological wastes can be converted to useful energy and other byproducts via biological or thermo-chemical routes. However, issues such as techno-economic feasibility and lack of understanding on the overall lifecycle of a product have hindered commercialization. It is needed to recognize these inter-disciplinary factors. This review attempts to critically evaluate the role of technology, economics and lifecycle assessment of bio-waste in two processing types. This includes: 1. biological and, 2. thermo-chemical route. The key findings of this work are: 1. Policy support is essential for commercialization of a waste treatment technology; 2. adequate emphasis is necessary on the social dimensions in creating awareness; and 3. from a product development perspective, research should focus on industrial needs. The choice of the treatment and their commercialization depends on the regional demand of a product, policy support, and technology maturity. Utilization of bio-wastes to produce value-added products will enhance circular economy, which in turn improves sustainability.
... The digestion process produces biogas and decontaminated water [13]. 'Dry' anaerobic digestion technologies operate with higher solid content and produce greater heat [14]. ...
The growing development nowadays on Mozambique is directly associated to the crescent industrialization and the increasing number of the population on enormous cities of the Nation, what needs more electrical energy and produce more garbage; uncontrolled and putting it in a challenge to face this scenario. Maputo City is facing huge problem with the Town Massive Garbage (TMG), without the structure to treat it, which deposited in the open dumpsite out of normal conditions, contributing for many diseases and environment impact, when it is burnt or it burns spontaneously, the subterranean water body is contaminated with leachate (methane); and proximately 72% of population or citizens have not electrical energy. The intention of this task is principally to turn the Town Massive Garbage into electrical energy in Maputo City the capital of the country, taking on the different technologies according to the garbage’s conditions and increase the capacity of energy which is approximately to 20% on the Country and to reduce the impact of environment from the landfill and, the number of landfill and dumpsites, working and attempting to achieve the sustainable development goals. The country has been recording constant interruptions of power supply due to increased energy demand resulting from the development of their Citizen, construction of new industrial, hotel and Office building together with housing. The motivations is to apply garbage as other innocuous source of power or energy, knowing that in the country mainly hydropower and solar, wind, biomass in a small quantity, coal, fuel are vanishing; reduce the impact of environment, global warm and ailments caused by it. The methodologies used to achieve the objectives are thermodynamics, heat transfer expressions and the COCO-OPEN simulation methodology to predate the energy generate from the composition and quantity of MSW. The results illustrates the possibility to enforce Town massive Garbage as source of energy or power, clearly taking in account the track conditions, as the heating value of it is nearly equal to the coal value which has been used to generate energy in many plants around the world. Municipal solid waste should be the future source of electricity to many developing countries if they create the structure to deal with it, treating, separating in different categories, controllin
... A few studies [6][7][8] have demonstrated the potential of SC for the production of biofuels, with the primary process involving pretreatment, hydrolysis, and fermentation. However, an industrial scale-up of the production process using such a material is still limited by several technological issues, which considerably increase the overall cost of investment and operation [9,10]. One of the key concerns is the large quantity of water used during bioconversion and the large size of upstream process equipment, which calls for high capital costs [11]. ...
PurposeBiomass slurries, such as those subjected to microwave-assisted alkaline (MAA) pretreatment, will become common substrates for the production of biofuels in the future. While the rheology of acid and ionic liquid pretreated biomass is known, the rheology of alkaline pretreated biomass is not yet reported; hence, the goal of this study was to establish the rheological characteristics of untreated and MAA pretreated sugarcane straw (SC).Methods
Using rotational rheometry and rheological models, the rheology of SC slurries was assessed as a function of particle size and insoluble solids concentration.ResultsIn the range of 5–17% insoluble solids concentration, the slurries were consistently pseudo-plastic (n = 0.33 ± 0.02), possessed yield stress with their flow accurately described by the Casson rheological model (R2 = 0.98–0.99). The apparent viscosity and yield stress increased by two orders of magnitude with an increase in insoluble solids concentration. Essentially, MAA pretreated slurries exhibited significantly higher values of apparent viscosity and yield stress than the untreated ones, in the range of 55–80% and 21–63% for particle sizes of < 63 µm (P63) and 90–180 µm (P90), respectively. Pretreated P63 samples exhibited higher apparent viscosity and yield stress than the P90. On the other hand, for untreated samples, P63 samples had a reduced apparent viscosity than P90 samples.Conclusion
The results of this study definitively reveal that MAA significantly increases the shear rate dependent shear viscosity values along with the yield stress of biomass slurries. This will, therefore, serve as a benchmark for characterizing other MAA pretreated biomass slurries to guide the design of industrial-scale production equipment.Graphic abstract
... These waste biomasses are the best feedstock for the production of bioethanol. The production of bioethanol must involve this feedstock rather than the food grains due to limited supplies (Nair et al. 2016). Many countries define bioenergy as energy obtained from biodegradable wastes and residues from agriculture like fruits and vegetables (Panda et al. 2018). ...
The increasing utilization of fossil fuel causes environmental pollution in addition to the depletion of the reserves. Hence, there is a need to search for alternative, renewable energy sources for the sustainable production of biofuel. Among the biofuels available in the market, bioethanol is a dominant liquid fuel. Fruit and vegetable wastes rich in sugars are one of the cheaper renewable sources for bioethanol production. Hence, utilizing these renewable wastes as a feedstock for bioethanol production would reduce the cost and also solve the issue of waste disposal. This chapter explains the bioethanol production using fruits and vegetable wastes, which are considered to be decaying waste materials.
... Sugarcane cultivation takes up 40% of the total island area as of 2010 [1]. The reduction of the price of sugar, reaching 36% by 2009, under a sugar protocol has resulted in considerable loss of earnings for the sector and the national economy [1,4,10]. ...
... Due to the inclusion of these pretreatment processes to facilitate the release of the fermentable sugars from waste samples, the complete ethanol production process becomes more expensive, complex, tedious and energy-consuming. This contributes to the major challenge associated with ethanol production from the banana peel or any other lignocellulosic wastes (Nair et al., 2016;Robak and Balcerek, 2018). ...
... This drove to the development of the second generation bio-ethanol production using woody solid biomass, energy crops, other agricultural, forestry products, and solid wastes (Mohr and Raman, 2013). However, it prompted negative production issues like energy-intensive process, high cost and the release of huge carbon dioxide from the processes and hydrolysis of cellulosic materials, physicochemical, and enzymatic treatments, giving rise to environmental contamination (Nair et al., 2016;Robak and Balcerek, 2018). Thereafter, researchers are working towards the third generation bio-ethanol production from algal biomass. ...
Ethanol tolerant strains were isolated from the marine waters of Digha and Shankarpur of West Bengal, India and screened for ethanol production using several domestic wastes including, paper, kitchen, garden, and fruit wastes. Strain E4 was found to be the most efficient in ethanol production through fermentation of kitchen and fruit waste. Phylogenetic analysis of the 16S rRNA gene of strain E4 showed its closeness to Citrobacter sp. Production of 2.96 g/L of ethanol was obtained using fruit waste using High-Performance Liquid Chromatography (HPLC) analysis. The yield of ethanol production was obtained as 0.13 g of ethanol/g of reducing sugar present in fruit waste. Although after optimization of fermentation condition, the yield was improved to 0.30 in batch scale. The production was optimized using Central Composite Design. The production was scaled up to 4 L culture volume in the stirred tank bioreactor. Finally, a distillation of fermentation broth resulted in 16.10 ml of product with a yield of 0.30 g of ethanol from 1 g of fruit waste. Thus the isolated marine strain Citrobacter sp. E4 could be potentially used for ethanol production from fruit wastes without any pretreatment in a cost-effective and eco-friendly way.Ethanol tolerant strains were isolated from the marine waters of Digha and Shankarpur of West Bengal, India and screened for ethanol production using several domestic wastes including, paper, kitchen, garden, and fruit wastes. Strain E4 was found to be the most efficient in ethanol production through fermentation of kitchen and fruit waste. Phylogenetic analysis of the 16S rRNA gene of strain E4 showed its closeness to Citrobacter sp. Production of 2.96 g/L of ethanol was obtained using fruit waste using High-Performance Liquid Chromatography (HPLC) analysis. The yield of ethanol production was obtained as 0.13 g of ethanol/g of reducing sugar present in fruit waste. Although after optimization of fermentation condition, the yield was improved to 0.30 in batch scale. The production was optimized using Central Composite Design. The production was scaled up to 4 L culture volume in the stirred tank bioreactor. Finally, a distillation of fermentation broth resulted in 16.10 ml of product with a yield of 0.30 g of ethanol from 1 g of fruit waste. Thus the isolated marine strain Citrobacter sp. E4 could be potentially used for ethanol production from fruit wastes without any pretreatment in a cost-effective and eco-friendly way.
... Generally, the conversion of LCB to bioethanol usually starts with a preliminary step of feedstock preparation that involves cleaning and size reduction by milling, grinding, or chopping, consuming a large amount of energy [8,42]. Subsequently, the process follows four major steps as shown in Figure 1 [43,44]: Pretreatment, to degrade lignocellulosic network into its fractions; Hydrolysis/Saccharification, to obtain fermentable sugars; Fermentation, to convert sugars into ethanol; and, Recovery and dehydration, to separate and purify the obtained ethanol. ...
Due to the health and environment impacts of fossil fuels utilization, biofuels have been investigated as a potential alternative renewable source of energy. Bioethanol is currently the most produced biofuel, mainly of first generation, resulting in food-fuel competition. Second generation bioethanol is produced from lignocellulosic biomass, but a costly and difficult pretreatment is required. The pulp and paper industry has the biggest income of biomass for non-food-chain production, and, simultaneously generates a high amount of residues. According to the circular economy model, these residues, rich in monosaccharides, or even in polysaccharides besides lignin, can be utilized as a proper feedstock for second generation bioethanol production. Biorefineries can be integrated in the existing pulp and paper industrial plants by exploiting the high level of technology and also the infrastructures and logistics that are required to fractionate and handle woody biomass. This would contribute to the diversification of products and the increase of profitability of pulp and paper industry with additional environmental benefits. This work reviews the literature supporting the feasibility of producing ethanol from Kraft pulp, spent sulfite liquor, and pulp and paper sludge, presenting and discussing the practical attempt of biorefineries implementation in pulp and paper mills for bioethanol production.
... Generally, the conversion of LCB to bioethanol usually starts with a preliminary step of feedstock preparation that involves cleaning and size reduction by milling, grinding, or chopping, consuming a large amount of energy [8,42]. Subsequently, the process follows four major steps as shown in Figure 1 [43,44]: Pretreatment, to degrade lignocellulosic network into its fractions; Hydrolysis/Saccharification, to obtain fermentable sugars; Fermentation, to convert sugars into ethanol; and, Recovery and dehydration, to separate and purify the obtained ethanol. ...
Due to the health and environment impacts of fossil fuels utilization, biofuels have been investigated as a potential alternative renewable source of energy. Bioethanol is currently the most produced biofuel, mainly of first generation, resulting in food-fuel competition. Second generation bioethanol is produced from lignocellulosic biomass, but a costly and difficult pretreatment is required.
The pulp and paper industry has the biggest income of biomass for non-food-chain production, and, simultaneously generates a high amount of residues. According to the circular economy model,
these residues, rich in monosaccharides, or even in polysaccharides besides lignin, can be utilized as a proper feedstock for second generation bioethanol production. Biorefineries can be integrated in the existing pulp and paper industrial plants by exploiting the high level of technology and also the infrastructures and logistics that are required to fractionate and handle woody biomass.This would contribute to the diversification of products and the increase of profitability of pulp and paper industry with additional environmental benefits. This work reviews the literature supporting the feasibility of producing ethanol from Kraft pulp, spent sulfite liquor, and pulp and paper sludge, presenting and discussing the practical attempt of biorefineries implementation in pulp and paper mills for bioethanol production.
... In 2017, the production of bioethanol worldwide reached 105.5 million m 3 (REN21 2018). Though the global community has acknowledged the role of bioethanol for energy security; environmental and economic drawbacks of producing bioethanol from first-generation feedstocks (sugar or starch from sugarcane, corn, and wheat) have switched attentions of using second-generation feedstocks (municipal solid waste, crop residues, sludge, livestock manure, and others) (Nair et al. 2017). ...
The advocacy of producing biofuels from wastes would answer the call for energy and environmental sustainability. This call is very timely considering the issues of global warming, increasing greenhouse gas emissions, diminishing natural resources, and enlarging human population. For one, the increasing generation of waste pulps from the growing numbers of starch-producing industries using cassava (Manihot esculenta Crantz) has become alarming because the improper disposal of these causes putrefaction odor, leachate contamination on water bodies, illnesses/diseases of community residents, and so on. In this work, the potential of cassava waste pulps (CWP) from starch industry was assessed with regard to the extraction of bioethanol via aerobic fermentation. The effect of yeast loading (0–4 tsp) and mashing duration (3–11 min) was evaluated on their influence on the bioethanol yield in CWP fermentation through central composite design of the response surface methodology. The result showed that 5.93 ± 0.03 mL of bioethanol could be extracted from a kilogram of fresh CWP after 7-day aerobic fermentation at conditions of 7 min mashing duration (42 °C) and 1 tsp yeast loading. Yeast loading and mashing duration are both significant with regard to bioethanol production. The gas chromatography analysis revealed 0.08% v/v bioethanol in the fermentation broth.
... With increasing concerns over climate change and high energy consumption, there is an increased demand for the renewable fuel alternatives such as bioethanol and biogas (Wang et al. 2013;Wan et al. 2011). Energy crops, being an easily accessible biomass for bioenergy, are popular substrates for industrial-scale production of bioethanol and biogas; however they are now facing the food versus fuel dispute (Salehian and Karimi 2013;Nair et al. 2017). Therefore, alternative feedstocks must be utilized for a sustainable bioenergy generation. ...
Anaerobic digestion is a biochemical process where complex organic matter such as carbohydrates, proteins, and lipids degrade in the absence of oxygen and are converted into methane and carbon dioxide by the action of different groups of microorganisms. It is a sustainable waste management technology, which reduces and stabilizes organic wastes, recycles its nutrient and water content, while producing energy. Biogas reduces the demand for fossil fuels, since it can be used for the production of electric power and heat, or converted into vehicle fuel. Currently, methane production via anaerobic digestion is a steadily increasing industry in Europe and all over the world. This chapter focuses on the anaerobic digestion process and the parameters affecting its performance. It also describes briefly the current technologies for anaerobic digestion. Finally, since the degradation of organic material requires a synchronized action of different groups of microorganisms with different metabolic capabilities, this chapter also presents recent developments in molecular biology techniques as valuable tools to obtain in-depth understanding about this complex microbiological system.
... With increasing concerns over climate change and high energy consumption, there is an increased demand for the renewable fuel alternatives such as bioethanol and biogas (Wang et al. 2013;Wan et al. 2011). Energy crops, being an easily accessible biomass for bioenergy, are popular substrates for industrial-scale production of bioethanol and biogas; however they are now facing the food versus fuel dispute (Salehian and Karimi 2013;Nair et al. 2017). Therefore, alternative feedstocks must be utilized for a sustainable bioenergy generation. ...
Three different bioaugmentation cultures enriched from natural and engineered cellulolytic environments (cow and goat rumen, a biogas reactor digesting sorghum biomass) were compared for their enhancement potential on the anaerobic digestion of wheat straw. Methane yields were determined in batch tests using the Automatic Methane Potential Test System operated for 30 days under mesophilic conditions. All cultures had positive effects on substrate degradation, and higher methane yields were observed in the bioaugmented reactors compared to control reactors set up with standard inoculum. However, the level of enhancement differed according to the type of the enrichment culture. Methane yield in batch reactors augmented with 2% cow rumen derived enrichment culture was increased by only 6%. In contrast, reactors amended with 2% goat rumen derived enrichment culture or with the bioaugmentation culture obtained from the biogas reactor digesting sorghum biomass produced 27% and 20% more methane, respectively. The highest methane yield was recorded in reactors amended with 6% goat rumen derived enrichment culture, which represented an increase by 36%. The microbial communities were quite similar at the end of the batch tests independently of the bioaugmentation sources, indicating that the introduced microbial communities of the enrichment cultures did not dominate the reactors.
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... However, many research have been carried out on the investigation of the production of bioethanol from various renewable resources such as; waste biomass of lignocellulosic and starch-based origin, such as municipal solid waste, industrial waste (waste paper or coffee residues), livestock manure, and agricultural waste (wood biomass and agricultural crop residues) [58]. Also, numerous studies across the world have been investigated bioethanol production from different types of fruit wastes. ...
The rapid increase in the world population has caused an enormous increase in the demand of energy. Growing demand has resulted in a shortfall in conventional energy resources. Due to that and because of the major negative impacts of fossil fuel on the environment and other aspects as well, the necessity toward finding alternative cheap, renewable, and environmentally friendly energy resources has significantly arose. Biomass as an energy resource has a potential to be a good alternative for non-renewable energy resources. Anaerobic digestion process is one of the most commonly biological conversion process used in converting biomass into biofuels. It has been extensively applied in many studies for converting several types of feedstocks and has proved its significant effectiveness. (AD) digestates are generally composed of solid and liquid streams. Those streams are rich in nutrients and contain undigested materials which have not been digested in the digestion process. Despite the significant effectiveness, it would contribute in major issues if it has been applied at large scale, as the amount of digestates which would be generated is quite high. Due to that and to take an advantage of the digestates in the production of biofuel and bioproducts as well, the interests in enhancing and utilizing anaerobic digestion residues have recently much increased. Bioethanol is one of the most promising liquid biofuel. It is eco-friendly alternative to fossil fuels. In recent years, number of studies have investigated the integration approach of producing biogas and bioproduct in which would result in zero waste. However, this paper discusses mainly an integration approach for producing two promising renewable energies can be utilized in many applications with no waste generated. This approach is still at an early stage and requires further studies to improve the properties of the biofuels and high-value bio-based products produced.
... Therefore, the recycling of agricultural waste works to safe and healthy rid from these waste and makes it economically beneficial. With the increase in claims to application of sustainable building standards, which will help in reducing the use of natural resources and increase the ability to re-use these materials and products for the same purpose, which will reduce waste; so, the agricultural waste that has been recycled must be used into sustainable building applications that are ecofriendly composites [13][14][15][16][17]. ...
Synthesis effect of mixing two types of nanoparticles in the same matrix polyester based sustainable composite was studied in this article. The nanoparticles blend includes sunflower seeds and calcium carbonate with amount 1–3 wt.%. Results showed that the samples containing sunflower seed nanoparticles have high impact strength compared to the samples with calcium carbonate, and increases with increasing reinforcement ratio compared with sample having calcium carbonate nanoparticles.
This chapter briefly explains the anaerobic digestion system to optimize biogas production and integrate digestion stabilization in rural semi-lot digesters, using agro-industrial waste mixtures to establish C/N ratios; with and without the inclusion of methanogenic inoculants. A second topic refers to obtaining second generation bioethanol from lignocellulosic wastes. General concepts of biogas and bioethanol production, related parameters and typical production schemes are described. On the other hand, it will focus on the application of fermentative processes as an activity of three different bacterial communities in biogas production and on induction systems using microorganisms to obtain bioethanol. The symbiosis between microorganisms will be presented, in the sense that in fermentation processes, metabolic actions of several microorganisms act together. In the final part, some practical applications related to the installation and start up of rural biodigesters are presented. In the case of lignocellulosic materials, pre-treatments, and processes for obtaining second generation bioethanol will be presented, as well as the current market trend. Similarly, it seeks to show the benefits for users, society and the environment, in the sectors of energy production, transformation of organic waste into high quality fertilizers, improvement of hygienic conditions, reduction or elimination of wood consumption and environmental advantages.
Bionanocomposites are hybrid materials comprising inorganic nanoparticles or nanofillers disposed in a biopolymer matrix. Different functional materials have been prepared using a wide type of biopolymers (naturally or synthetic) and inorganic particles (silica, metal, carbon nanotubes, cellulose nanowhiskers or layered silicate clays) with different compositions and topologies. In this chapter, special attention is paid in layered silicates because of their availability, low cost and their easy intercalation chemistry. The natural polysaccharides (chitosan, starch and alginate), proteins and the synthetic polylactic acid incorporating to layered silicates of the smectite group constitute the bionanocomposites most studied for environmental applications. In this work, the physicochemical and structural properties of developed bionanocomposites including the different methods of preparation and characterization techniques have been discussed. Finally, environmental applications of bionanocomposites based on layered silicates in the field of food, agriculture, soil and water treatments, both in cleaning and desalination, are contemplated.KeywordsBionanocompositesBiopolymersLayered silicatesAdsorptionWater remediation
The rapid growth of science and technology has led us to see new achievements in the field of biomedical every day. Recent studies have identified polymers as an important member of the biomedical sciences used in various fields and various forms.
During the last few decades, scientists are engaged to develop cost-effective and eco-friendly synthetic natural therapeutic materials.
Bionanocomposites are class of bio-based nanostructured hybrid materials, which exhibit at least one dimension on the nanometer scale. In general, bionanocomposites are comprised of biopolymers and other organic or inorganic sources. Cellulose and chitin are the two most abundant biological polymers in nature. In recent decades, cellulose and chitin-based bionanocomposites have triggered a great deal of attention to understand such composite materials and their applications. Thanks to their renewable, biodegradable, biocompatible, low-cost, low-density, eco-friendly properties, and low energy consumption, cellulose and chitin-based bionanocomposites are excellent green technology materials. Currently, cellulose and chitin-based bionanocomposites are widely used in a variety of fields, such as environmental protection, electronics device industry, biomedicine industry, food industry, and agriculture industry. In this chapter, the sources and properties as well as the extraction and preparation methods of the corresponding cellulose and chitin bionanocomposites are introduced. The environmental characteristics of cellulose and chitin-based bionanocomposites and their applications in various fields are reported.
The average production of agricultural products globally has reached 23.7 million tons of food per day in recent years, while the destruction and waste of food annually account for a significant amount of this reform [1]. The Food and Agriculture Organization (FAO) estimates that about 1.3 billion tons of food is wasted annually, or about 15% of total annual production [2]. This number is equivalent to 33% of the average daily consumption of an adult. The U.S. Department of Agriculture (USDA) says a significant portion of this food spoilage occurs at the retail level, most related to vegetables and fruits [3]. Smarter use of food packaging can significantly reduce the waste of various foods [4].
Increasing municipal solid waste (MSW) generation and environmental concerns have sparked global interest in waste valorization through various waste-to-energy (WtE) to generate renewable energy sources and reduce dependency on fossil-derived fuels and chemicals. These technologies are vital for implementing the envisioned global “bioeconomy” through biorefineries. In light of that, a detailed overview of WtE technologies with their benefits and drawbacks is provided in this paper. Additionally, the biorefinery concept for waste management and sustainable energy generation is discussed. The identification of appropriate WtE technology for energy recovery continues to be a significant challenge. So, in order to effectively apply WtE technologies in the burgeoning bioeconomy, this review provides a comprehensive overview of the existing scenario for sustainable MSW management along with the bottlenecks and perspectives.
Peningkatan kebutuhan energi terutama bahan bakar minyak yang tidak diimbangi dengan ketersediaan sumber energi tak terbarukan akan mengakibatkan kelangkaan energi. Pembuatan bahan bakar terbarukan merupakan solusi untuk mengatasi kelangkaan tersebut, salah satunya bioetanol. Biomassa Tandan Kosong Kelapa Sawit (TKKS) merupakan bahan baku yang cocok untuk pembuatan bioetanol karena jumlahnya yang melimpah dan mengandung lignoselulosa. Bioetanol dapat diperoleh melalui proses fermentasi dengan metode yang digunakan adalah Fed Batch Simultaneous Saccharification Fermentation. Pretreatment berupa size reduction dan delignifikasi direkomendasikan sebelum proses hidrolisis enzimatik dan fermentasi secara serentak. Metode pengumpanan Fed Batch pada High Total Solid Loading (HTSL) direkomendasikan sebagai strategi pengumpanan pada proses hidrolisis enzimatik dengan jumlah frekuensi yang tinggi memberikan hasil kadar etanol lebih tinggi.
The enhancement of energy needs, especially fuel, that is not complemented by the availability of non-renewable energy sources, would affect the deficient of energy. The production of renewable fuel such as bioethanol is a solution to overcome that deficiency. One of the substrates that are appropriate to be processed into bioethanol is Oil Palm Empty Fruit Bunch (OPEFB) because of abundant and lignocellulosic biomass. Bioethanol can be produced through the fermentation process by Fed-Batch Simultaneous Saccharification Fermentation method. Size reduction and delignification for pretreatment are recommended before the simultaneous enzymatic hydrolysis process and fermentation. Using the fed-batch as a feeding method of High Total Solid Loading (HTSL) is recommended for feeding strategy in hydrolysis enzymatic process with high frequency that can produce a higher yield of ethanol.
With the rise in global population, industrialization, and economic expansion, the persistent overconsumption of conventional fossil fuels has resulted in the depletion of fossil fuel reserves. This has fuelled the need to investigate and boost scientific research efforts on sustainable and renewable bioenergy feedstock. A substitute that can minimize reliance on nonrenewable energy resources while also lowering greenhouse gas emissions. In this context, biofuels have received a great deal of interest in recent years as a prospective substitute for conventional fossil fuels. The prime reason behind this is the feedstock utilized in their synthesis. The feedstocks employed here are environmentally safe, nontoxic, and emit little to no pollution. These feedstocks are classified into four generations: first, second, third, and fourth. Food crops and lignocellulosic biomass and waste constitute first- and second-generation feedstocks. The third- and fourth-generation feedstock is microalgae. This paper provides a comprehensive overview of feedstocks utilized to produce biofuels, including the various pre-treatment methods, strategies, and techno-economic analysis in order to pave the way for next-generation biofuels. It also covers the advantages, drawbacks, challenges, and current developments.
The waste-to-wealth concept has attracted remarkable attention for generating values out of waste materials along with the effective management of notorious agri-food wastes. Globally, agri-food industries are generating daily mammoth pre- and postprocessing wastes, of which most of the untreated waste fractions are severely leading to environmental problems. This waste can be designed to be valorized in a sustainable way with cutting-edge technologies not only to generate value-added products but also to offer jobs. Valorization of agri-food wastes into alternative and renewable energy generation is a popular practice in several industries to meet the in-house energy requirement as well as for returns to offset the economic constrain of the ongoing process. Moreover, bio-energy from waste has been an efficient alternative resource for the depleting fossil fuel usage, which also improves the carbon footprint of the bioprocess. Today, food waste is a comparatively less explored resource mainly due to its high organic nature. The technological hurdles are associated with utilizing it as the main source for generating valuable bioproducts. The agro-food processing waste has been utilized for the production of bioactive molecules, platform chemicals, biofertilizers, enzymes, etc.
Most of the cities in India are under the severe threat of air pollution. In this context, particulate pollution seems to play a pivotal role in the total air pollution perspective for an area. In view of the inevitable threat posed by the particulate fractions (PM 10), the present paper tries to highlight the dominance of the particulate fractions on the air quality of an area. The two sampling sites chosen were Agra (27 o 10'36.0120"N, 78 o 0'29.0592"E) and Mumbai (18 o 58'30"N, 72 o 49'33"E), both highly polluted and driven by intense traffic combustion. The other pollutants taken into consideration in the study are sulphur dioxide (SO 2) and nitrogen dioxide (NO 2). The dominance of the particulate fractions to the total air pollution in the two areas have been reflected in terms of the air pollution index (API) and exceedance factor (EF). In fact, it has been observed that throughout the three years the API calculated with respect to PM 10 is about 2.688 and 1.476 times than those calculated considering the contribution of all the three pollutants together for Agra and Mumbai, respectively. As for the EF, the average EF for PM 10 has been found to be 2.666 for Agra and 1.825 for Mumbai over the three years of study. Lastly, an attempt has been also made in the paper to present the seasonal variation of the pollutants over the three years of study.
Ethanol production from lignocellulosic biomass has been practised since a long time. Many substrates as fruit waste, vegetable waste, residues from the crops have been in consideration and proved to be the sustainable feedstock. The research work is performed using Tagetes erecta (marigold flowers) fermented by Saccharomyces cerevisiae yeast strain. The moisture content of the flowers was observed to be 79.2%. Pre-treatment was carried out with normal and hot water that will loosen up the fibres present. The chemical methods were used as to convert starch present in flower to monomer units and then fermented to produce ethanol. The maximum ethanol yield observed was 15.87 g/L at 72 h corresponding to temperature of 30 °C and pH 4.5. The aim is to develop an environment friendly method for recycling of the flowers and also provides a proper solution to the waste generated from temples and from ceremonies.
Humanity is struggling against a major problem for a proper management of generated municipal solid waste. The collected waste causes natural issues like uncontrollable emission of greenhouse gases. Even though, escalation of waste results in minimizing the areas accessible for disposing the waste. Creating awareness in the society to use organic products like biofuels, biofertilizers and biogas is a need of an hour. Biochemical processes such as composting, vermicomposting, anaerobic digestion, and landfilling play important role in valorizing biomass and solid waste for production of biofuels, biosurfactants and biopolymer. This paper covers the details of biomass and solid waste characteristics and its composition. It is also focused to provide updated information about reutilization of biomass for value creation. Technologies and products obtained through bio-routes are discussed in current review paper together with the integrated system of solid waste management. It also covers challenges, innovations and perspectives in this field.
The gargantuan escalation in the myriad of plastic waste in emerging and developing countries has led to the augmented atrocities concerning the environmental impact and health disquietude due to their ubiquitous nature. Burgeoning in the conversion of plastic waste into energy is a captivating strategy to circumvent the power generation shortages, greenhouse gas emissions, restricted space for landfilling, and can unravel the emanation of plastic waste disposal. Indeed, this transformation sporadically enunciated as a magic bullet to address all impediments created by plastics in municipal solid waste. Plastic waste recycling has empirical significance and commercial worth for recuperation of resources and environmental welfare but to attain sustainable development , emphasis on the metamorphosis of waste into energy by employing greener technologies should be implemented. Howbeit, the prolegomenon of plastic waste to energy innovation is usually jeopardized by recurrent deterrents like operation costs, fund investments, environmental laws, etc. In this contrivance, assessment and fate of plastic waste to energy has been addressed to harmonize the nuisance originated by prevailing plastic wastes. The design and fabrication of technology implemented to transform plastic waste into energy have been inscribed by demarcating challenges and hindrances with their life cycle assessment process. Novel integrated energy plants employing renewable sources such as solar cells for revamping plastic trash are discussed aiming to motivate communities to recycle and reuse the waste in a sustainable way. Circuit based simulation model proffers an estimation of the electrical behaviour of renewable energy integrated systems with respect to alterations in environmental parameters including temperature and irradiation. This robust overview also unfurls the bottlenecks in the valorization of plastic waste into energy with bestowing potential panacea towards a better sustainable society.
With ever increasing waste production worldwide, the development of newly emerging technologies is rising and advancing proportionately. Entailed instalment of sophisticated energy‐producing plants is constantly expanding to meet the socio‐economic demands of communities and industries. Innumerable superior technologies have been introduced to minimise waste pollution while reducing emissions of greenhouse gases hence, combatting the impact of global warming. This review shows energy conversion technologies including gasification, pyrolysis, incineration, landfill, and bioelectrochemical technologies mainly microbial fuel cell (MFC), microbial electrolysis cells (MECs) and microbial electrosynthesis (MES). Traditionally, incineration and landfill are the main mean of waste conversion but not favourable because of their side effects, economic viability, secondary pollution and difficulty in mechanical compression. Recently, biological processes including anaerobic digestion have gained huge interest but possess some inherent drawbacks and cannot provide a comprehensive solution for future waste management. Among energy converting technologies, bio‐electrochemical MFC system is highly preferred as an elementary, clean, safe, economically viable and environmentally beneficial technology. MFC a renewable energy technology possesses multidimensional applications of producing electric power and treat wastewater. In addition, the MFCs can be modified into MEC to generate hydrogen energy from various organic matters. Prospective modification recommendations for scale‐up application of this technology are also presented. Large scale waste production and energy crises are important global issues. Many waste managing and energy generating technologies have been introduced. Thermal and non‐thermal technologies are discussed. Use of Microbial fuel cells technology for energy crisis as a preferred technology.
The growth in population and condition of the economy has increased the dependency on fossil fuels to meet energy demands. Extensive use of fossil fuels has led to increased emissions of CO2, rising atmospheric temperatures, deteriorating air quality, thus ultimately leading to climate change. This has led countries and governments to seek out more renewable and sustainable alternatives that can replace fossil fuels. Bioethanol is one of the most promising biofuels to have successfully become one of the best alternatives to fossil fuels. Ethanol can be produced both from agri crops like barley, oats, rice, wheat, etc., as well as from lignocellulosic biomass feedstock and other wastes. All the different kinds of biomass constitute sugars in high concentrations which when fermented produce bioethanol. The quantity and quality are determined through different types of methods like pre‐treatment, hydrolysis, fermentation, and distillation.
This chapter will provide a comprehensive study of the biorefinery approach to bioethanol production. The consecutive steps leading from the type of biorefinery to further purification of ethanol will also be discussed.
Municipal solid waste management is one of the major issues throughout the world. Inappropriate management of municipal solid waste (MSW) can pose a major hazard. Anaerobic processing of MSW followed by methane and biogas generation is one of the numerous sustainable energy source options. Compared with other technologies applicable for the treatment of MSW, factors like economic aspects, energy savings, and ecological advantages make anaerobic processing an attractive choice. This review discusses the framework for evaluating conversion of municipal solid waste to energy and waste derived bioeconomy in order to address the sustainable development goals. Further, this review will provide an innovative work foundation to improve the accuracy of structuring, quality control, and pre-treatment for the ideal treatment of different segments of MSW to achieve a sustainable circular bioeconomy. The increasing advancements in three essential conversion pathways, in particular the thermochemical, biochemical, and physiochemical conversion methods, are assessed. Generation of wastes should be limited and resource utilization must be minimised to make total progress in a circular bioeconomy.
Waste generation is steadily growing in developing countries such as India due to the continuous growth of industrialization, urbanization, and population. Mismanagement of municipal solid waste (MSW) not only has negative environmental effects but also causes the risk to public health and raises some other socio-economic issues that are worth discussions. Therefore, it is essential to urgently enhance the handling of waste collection, segregation, and safe disposal. Waste-to-energy (WtE) technologies such as pyrolysis, gasification, incineration, and biomethanation can convert MSW, as an appropriate source of renewable energy, into useful energy (electricity and heat) in safe and eco-friendly ways. This review aims at (1) describing the challenges of MSW management, (2) summarizing the health significance of MSW management, (3) explaining the opportunities and requirements of energy recovery from MSW through WtE technologies, (4) explaining several WtE technologies in detail, and (5) discussing the current status of WtE technologies in India. The paper also discusses the challenges to WtE projects in India. Moreover, a number of recommendations are provided for improving the currently implemented solid waste management (SWM) in the Indian context. This review has the potential of helping scholars, researchers, authorities, and stakeholders working on MSW management to make effective decisions.
Water hyacinth, an aquatic weed, is contemplated as a toxic plant worldwide and also it spreads rapidly and attenuates nutrient and oxygen from water bodies and has harmful effects on both aquatic plants and animals. Native of Latin America, it spread now to all over the world and is mostly seen as a menace. However, unlike most weeds it has many beneficial aspects. Therefore, transformation of this troublesome noxious weed to better-quality products and conversion to efficient energy seems sustainable option for developing countries and needs to be explored. The present review focuses on the various recent studies on beneficial chemicals/products and biogas generated from water hyacinth as well as its probabilities of success in commercialization.
In recent years, the drive toward a sustainable economy has challenged the scientific community to pursue ambitious investigations to convert sustainable feedstocks such as lignocellulose into useful products. These products include biofuels, commodity chemicals, and new bio-based materials including bioplastics, which offer a potential substitution to the dwindling nonrenewable fossil resources. A plethora of lignocellulosic biomass processing technologies have been attempted and effectively documented in literature, which include, but not limited to, biochemical, liquid acid, thermochemical, and catalytic (homogeneous and heterogeneous catalysis) transformation processes. This chapter reviews the state-of-the-art research and development of these process technologies. We further highlight the advantages and disadvantages, potential for future applications, challenges related to these technologies, and opportunities to maximize economic and environmental benefits, while minimizing waste and pollution. Special emphasis is placed and discussed on the production of biofuels and commodity chemicals from these process technologies. Besides, the application of molecular modeling in integration with experiments is highlighted in this chapter as a new paradigm for mechanism study and thus could open up new avenues to design and develop catalysts for a plethora of biomass reactions that require high activity and selectivity.
Abrupt urbanization and industrialization around the world resulted in elevated environmental pollution and depletion of natural energy resources. An eco-friendly and economical alternate for energy production is the need of hour. This can be achieved by converting the waste material into energy. One such waste is lignocellulosic agricultural residues, produced in billions of tons every year all around the world, which can be converted into bioethanol. The main challenge in this bioconversion is recalcitrant nature of lignocellulosic material. The removal of cementing material that is lignin and to overcome the potential inhibitors produced during disintegration of lignin is the challenging task for biotechnologist. This task can be achieved by number of different methods but laccase is the most effective and eco-friendly method that can be used for effective removal of lignin along with increase the accessibility of cellulose and bioethanol yield.
The concept of biorefinery is illustrated here with some industrial example involving the production of biodiesel. Some general cases are given in regard to the production of ethanol. This is an introductory chapter where the focus is concentrated on some of the biggest Finnish companies working in this field and on process integration of different systems provided.
The major contributor to global warming is considered to be the high levels of greenhouse gas emissions, especially carbon dioxide (CO2), caused by the burning of fossil fuel. Thus, to mitigate CO2 emissions, renewable energy sources such as ethanol have been seen as a promising alternative to fossil fuel consumption. Brazil was the world's first nation to run a large-scale program for using ethanol as fuel. Eventually, the United States also developed large-scale production of ethanol. In this study, we compare the benefits and environmental impacts of ethanol fuel, in Brazil and in the United States, using the ecological footprint tool developed by Wackernagel and Rees. We applied the STELLA model to gauge possible outcomes as a function of variations in the ethanol production scenario.
Chiapas is one of the largest coffee-producing states in Mexico. In this industry, there are large quantities of waste, which are toxic and harmful to the environment. During the extraction process of coffee bean the waste generated are: pulp, mucilage and parchment. Recently, investigations have been done to utilize these residues for bioenergy generation. This paper provides an overview of coffee and one of its major industrial wastes. The objective of this research was the production of bioethanol from coffee mucilage at laboratory scale and extract and characterize the substrate used as raw material and establish a fermentation process for the production of bioethanol. Our results show the kinetics of fermentation of coffee mucilage as a substrate to yeast Saccharomyces cerevisiae. The cell density, concentration of ethanol, reducing sugar consumption, physico-chemical variables such as pH and temperature were analyzed. The Fermentation parameters such as growth rate, saturation constant and yields were estimated.
Rapid acidification and inhibition by d-limonene are major challenges of biogas production from citrus waste. As limonene is a hydrophobic chemical, this challenge was encountered using hydrophilic polyvinylidine difluoride (PVDF) membranes in a biogas reactor. The more sensitive methane-producing archaea were encapsulated in the membranes, while freely suspended digesting bacteria were present in the culture as well. In this membrane bioreactor (MBR), the free digesting bacteria digested the citrus wastes and produced soluble compounds, which could pass through the membrane and converted to biogas by the encapsulated cell. As a control experiment, similar digestions were carried out in bioreactors containing the identical amount of just free cells. The experiments were carried out in thermophilic conditions at 55 °C, and hydraulic retention time of 30 days. The organic loading rate (OLR) was started with 0.3 kg VS/m3/day and gradually increased to 3 kg VS/m3/day. The results show that at the highest OLR, MBR was successful to produce methane at 0.33 Nm3/kg VS, while the traditional free cell reactor reduced its methane production to 0.05 Nm3/kg VS. Approximately 73% of the theoretical methane yield was achieved using the membrane bioreactor.
Consolidated bioprocessing (CBP) is a promising technology for lignocellulosic ethanol production, and the key is the engineering of a microorganism that can efficiently utilize cellulose. Development of Saccharomyces cerevisiae for CBP requires high level expression of cellulases, particularly cellobiohydrolases (CBH). In this study, to construct a CBP-enabling yeast with enhanced CBH activity, three cassettes containing constitutively expressed CBH-encoding genes (cbh1 from Aspergillus aculeatus, cbh1 and cbh2 from Trichoderma reesei) were constructed. T. reesei eg2, A. aculeatus bgl1, and the three CBH-encoding genes were then sequentially integrated into the S. cerevisiae W303-1A chromosome via δ-sequence-mediated integration. The resultant strains W1, W2, and W3, expressing uni-, bi-, and trifunctional cellulases, respectively, exhibited corresponding cellulase activities. Furthermore, both the activities and glucose producing activity ascended. The growth test on cellulose containing plates indicated that CBH was a necessary component for successful utilization of crystalline cellulose. The three recombinant strains and the control strains W303-1A and AADY were evaluated in acid- and alkali-pretreated corncob containing media with 5 FPU exogenous cellulase/g biomass loading. The highest ethanol titer (g/l) within 7 days was 5.92 ± 0.51, 18.60 ± 0.81, 28.20 ± 0.84, 1.40 ± 0.12, and 2.12 ± 0.35, respectively. Compared with the control strains, W3 efficiently fermented pretreated corncob to ethanol. To our knowledge, this is the first study aimed at creating cellulolytic yeast with enhanced CBH activity by integrating three types of CBH-encoding gene with a strong constitutive promoter Ptpi.
The purpose of this study was to evaluate the global energy production potential of woody biomass from forestry for the year 2050 using a bottom-up analysis of key factors. Woody biomass from forestry was defined as all of the aboveground woody biomass of trees, including all products made from woody biomass. This includes the harvesting, processing and use of woody biomass. The projection was performed by comparing the future demand with the future supply of wood, based on existing databases, scenarios, and outlook studies. Specific attention was paid to the impact of the underlying factors that determine this potential and to the gaps and uncertainties in our current knowledge. Key variables included the demand for industrial roundwood and woodfuel, the plantation establishment rates, and the various theoretical, technical, economical, and ecological limitations related to the supply of wood from forests. Forests, as defined in this study, exclude forest plantations. Key uncertainties were the supply of wood from trees outside forests, the future rates of deforestation, the consumption of woodfuel, and the theoretical, technical, economical, or ecological wood production potentials of the forests. Based on a medium demand and medium plantation scenario, the global theoretical potential of the surplus wood supply (i.e., after the demand for woodfuel and industrial roundwood is met) in 2050 was calculated to be 6.1 Gm3 (71 EJ) and the technical potential to be 5.5 Gm3 (64 EJ). In practice, economical considerations further reduced the surplus wood supply from forests to 1.3 Gm3 year−1 (15 EJ year−1). When ecological criteria were also included, the demand for woodfuel and industrial roundwood exceeded the supply by 0.7 Gm3 year−1 (8 EJ year−1). The bioenergy potential from logging and processing residues and waste was estimated to be equivalent to 2.4 Gm3 year−1 (28 EJ year−1) wood, based on a medium demand scenario. These results indicate that forests can, in theory, become a major source of bioenergy, and that the use of this bioenergy can, in theory, be realized without endangering the supply of industrial roundwood and woodfuel and without further deforestation. Regional shortages in the supply of industrial roundwood and woodfuel can, however, occur in some regions, e.g., South Asia and the Middle East and North Africa.
Environmental issues and shortage of fossil fuels have turned the public interest to the utilization of renewable, environmentally friendly fuels, such as ethanol. In order to minimize the competition between fuels and food production, researchers are focusing their efforts to the utilization of wastes and by-products as raw materials for the production of ethanol. household food wastes are being produced in great quantities in European Union and their handling can be a challenge. Moreover, their disposal can cause severe environmental issues (for example emission of greenhouse gasses). On the other hand, they contain significant amounts of sugars (both soluble and insoluble) and they can be used as raw material for the production of ethanol.
Household food wastes were utilized as raw material for the production of ethanol at high dry material consistencies. A distinct liquefaction/saccharification step has been included to the process, which rapidly reduced the viscosity of the high solid content substrate, resulting in better mixing of the fermenting microorganism. This step had a positive effect in both ethanol production and productivity, leading to a significant increase in both values, which was up to 40.81 % and 4.46 fold, respectively. Remaining solids (residue) after fermentation at 45 % w/v dry material (which contained also the unhydrolyzed fraction of cellulose), were subjected to a hydrothermal pretreatment in order to be utilized as raw material for a subsequent ethanol fermentation. This led to an increase of 13.16 % in the ethanol production levels achieving a final ethanol yield of 107.58 g/kg dry material.
In conclusion, the ability of utilizing household food waste for the production of ethanol at elevated dry material content has been demonstrated. A separate liquefaction/saccharification process can increase both ethanol production and productivity. Finally, subsequent fermentation of the remaining solids could lead to an increase of the overall ethanol production yield.
A rice straw - cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 °C, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L(-1).
This paper looks critically at how food and agriculture-, energy security-, and climate change-oriented international organizations have consolidated and modified the biofuel discourse in relation to the agricultural system. Using Foucault-based genealogical analysis of discursive formations, the paper traces the last 20 years of institutions’ biofuel debate in relation to rural production. We find that the prevalent motive is an aspiration to combine the agriculture and energy markets into one, which prompts structural changes and challenges in the rural sector. This has implications for the future role and shape of global agriculture and – contrary to the food vs. fuel perspective – calls for re-conceptualizing the biofuel debate as the food vs. food dilemma.
Waste papers (newspaper, office paper, magazines and cardboard in this study) with 50–73% (w/w oven dry weight) carbohydrate contents have considerable potential as raw materials for bioethanol production. A particle size reduction step of wet blending prior to enzymatic hydrolysis of newspaper was found to increase the glucan conversion efficiency by up to 10%. High-solids loading hydrolysis at 15% (w/w) of four types of paper using two enzyme alternatives, Celluclast 1.5L supplemented with Novozyme 188 and Cellic Ctec 1 (Novozymes A/S, Demark), at various enzyme concentrations were successfully performed in a lab-scale overhead-stirred reactor. This work has identified the relative saccharification performance for the four types of paper and shows office paper and cardboard to be more suitable for producing bioethanol than newspaper or magazine paper. The experimental data were also very well described by a modified, simple three parameter glucan and xylan hydrolysis model. These findings provide the possibility for incorporating this validated kinetic model into process designs required for commercial scale bioethanol production from waste paper resources.
Bioethanol production from dry cashew apple pulp and coffee pulp was investigated. The pulp was digested with 2% sulfuric acid and subjected to high pressure (15 psi) cooking at 120 °C for 10 min followed by further 1 and a half hour pressure cooking at 90 °C to solubilize the pulp. Solubilized pulp was filtered and the debris on the filter paper was washed with minimum quantity of distilled water and then oven dried to find the weight of the insoluble lignin mass. Total sugar content in squeezed and dried cashew apple pulp (CAP), dry coffee pulp (DCP) and wet coffee pulp (WCP) was found to be 2.12, 1.62 and 0.62 g/100 ml of hydrolyzate. Reducing sugar content in squeezed CAP, DCP and WCP was found to be 0.14, 0.71and 0.23g/100 ml of hydrolyzate. Filtrate was neutralized with thick suspension of calcium hydroxide slurry until the pH reaches to 6.0. Neutralized slurry was kept at lab temperature overnight and the supernatant was decanted through filter paper. To 150 ml of filtrate yeast (Saccharomyces creviciae) was added at a concentration of 5.0 g/l concentration and subjected to fermentation for 48 h at 30 °C in a shaker incubator at 120 rpm. Ethanol content in the fermented broth was estimated by titrimetric and gas chromatographic method. Ethanol yield in the fermented broth was found to be 0.5, 0.46 and 0.46 g/g of sugar in squeezed CAP, DCP and WCP. Theoretical ethanol yield (Ymax%) of squeezed CAP, DCP and WCP was found to be 46, 9.35 and 40% respectively.
For the purpose of exploring low-cost feedstocks for ethanol production and seeking environmental-friendly alternatives in waste disposal, enzymatic hydrolysis of cellulose from three types of feedstock from waste streams were studied: crop residues, poultry manure, and sewage sludge. The crop residues investigated include corn stalk and bagasse; they were pre-treated with KOH prior to enzymatic hydrolysis. At 40 °C, with an enzyme loading of 800 units/g substrate, the glucose yields from enzymatic hydrolysis of corn stalk and bagasse were 65.4 ± 2.3% and 51.1 ± 2.3%, respectively. The enzymatic hydrolysis of corn stalk was further optimized by using wet substrate, which was grinded before KOH treatment, and by adding half of the enzyme dosage at the beginning of the process and half in the middle of the hydrolysis instead of adding the entire dosage at the beginning. For poultry manure, the highest glucose conversion was achieved when it was treated with KOH and then dried and grinded prior to enzymatic hydrolysis. At operating conditions of 40°C and enzyme loading 400 units/g substrate, the glucose yield from poultry manure was 27.6±1.2%. Under the same optimum conditions as those observed for crop residues, 31.1±2.7% of wet primary sludge was converted to glucose, and it was increased to 54.2±4.0% when HCl and KOH pre-treatments were employed.
Lignocellulosic biomass is an attractive alternative material for bioethanol fuel production. Lignocellulose is the most abundant renewable resource on Earth, and it constitutes a large component of the wastes originating from municipal, agricultural, forestry, and some industrial sources. The more widespread geographical distribution of lignocellulose sources, compared to fossil reserves, can provide security of supply by using domestic sources of energy. The use of lignocellulosic materials would minimize the conflict between land use for food (and feed) production and energy feedstock production. This raw material is less expensive than conventional agricultural feedstock and can be produced with lower input of fertilizers, pesticides, and energy. Biofuels from lignocellulose generate low net GHG (greenhouse gas) emissions, reducing environmental impact, particularly on climate change. Currently, some countries are producing ethanol from cellulosic feedstock at different development stages, and several public/private international projects have been developed in the biorenewable sector to promote a bio-based economy. Depending on the feedstock considered, its availability for bioethanol production can vary considerably from season to season, and depending on geographic locations, could also pose difficulty in their supply. The changes in the price of feedstocks can highly affect the production costs of bioethanol. Because feedstocks typically account for greater than one third of the production costs, maximizing bioethanol yield would be imperative. Each country must find the best and economical way to use their feedstocks and residues in order to produce biofuels. Brazilian bioethanol program is an example of the efficiency of sugarcane production and high technology bioethanol production.
The composition of 44 sludges from 30 paper mills was examined. The sludges averaged 33 wt.% solids. Glucan was the dominant carbohydrate. The mean ash content was 26.4%. Thirty-six sludge samples were examined with respect to enzymatic hydrolysis and conversion to ethanol in a simultaneous saccharification and fermentation (SSF) system. Supplemental beta-glucosidase had a marked positive effect on ethanol yield, but cellulase loading and growth medium did not affect ethanol yield. Dewaterability improved for most sludges following SSF. The potential values of paper sludge components were determined.
A key factor about the use of lignocellulosic materials to produce bioethanol is the pre-treatment step, because the lignocellulosic materials are not easily hydrolyzed by the enzymes if their crystalline structure and the lignin seal are not destroyed before. In this work the treatment of white office paper by means of the Liquid Hot Water (LHW) pretreatment is investigated. Effects of LHW are examined in a laboratory plant, with respect to the solids dissolution and sugar yields after enzymatic treatment.
In this study, a hydrophobic polymeric polydimethylsiloxane (PDMS) membrane was used for the pervaporative separation of bioethanol produced from fermentation of lignocellulosic biomass (waste newspaper) and glucose. As a preliminary study, the pervaporation permeation performance showed strong dependence on feed concentration and temperature. The pervaporation of bioethanol produced by the fermentation of waste newspaper by Saccharomyces cerevisiae decreased process performance. However, the process performance was restored reversibly by water cleaning. The pervaporative separation of bioethanol from the fermentation of waste newspaper was carried out without any significant decreasing process performance in the study.
This study deals with the production of ethanol and paper pulp in a kraft pulp mill. The use of an acid hydrolysis or a two-step treatment composed of an autohydrolysis followed by a secondary acid hydrolysis was studied. Acid hydrolysis allowed the extraction of higher quantities of sugars but led also to higher degradations of these sugars into inhibitors of fermentation. The direct fermentation of a hydrolysate resulting from an acid hydrolysis gave excellent yields after 24 h. However, the fermentation of hydrolysates after their concentration proved to be impossible. The study of the impact of the inhibitors on the fermentations showed that organic acids, and more specifically formic acid and acetic acid were greatly involved in the inhibition.
The production of ethanol from wheat straw (WS) by dilute acid pretreatment, bioabatement of fermentation inhibitors by a fungal strain, and simultaneous saccharification and fermentation (SSF) of the bio-abated WS to ethanol using an ethanologenic recombinant bacterium was studied at a pilot scale without sterilization. WS (124.2 g/L) was pretreated with dilute H2SO4 in two parallel tube reactors at 160 °C. The inhibitors were bio-abated by growing the fungus aerobically. The maximum ethanol produced by SSF of the bio-abated WS by the recombinant Escherichia coli FBR5 at pH 6.0 and 35 °C was 36.0 g/L in 83 h with a productivity of 0.43 g L−1 h−1. This value corresponds to an ethanol yield of 0.29 g/g of WS which is 86% of the theoretical ethanol yield from WS. This is the first report on the production of ethanol by the recombinant bacterium from a lignocellulosic biomass at a pilot scale.
Fir wood wastes were used to produce crude bio-ethanol by two methods: simultaneous saccharification and fermentation (SSF) and acid hydrolysis followed by the fermentation of the acid hydrolyzate. The main components of crude bio-ethanol are ethanol and acetic acid. In addition, low concentrations of a wide range of alcohols, acids, esters, ethers and aldehydes are also present. Ethanol concentration is higher in the SSF process than in the acid hydrolysis: 43.69 g/L compared to 37.53 g/L, respectively. Opposite to ethanol concentration, the acetic acid concentration is higher in the acid hydrolysis process: 16.36 g/L compared to 10.24 g/L, respectively. The crude bio-ethanol was used to produce hydrogen by catalytic steam reforming. The tested catalysts were the common Ni/Al2O3 and two rare earth oxides promoted Ni catalysts: Ni/La2O3–Al2O3 and Ni/CeO2–Al2O3 prepared by successive wet impregnation. The characterization techniques revealed that the addition of rare earth oxides improves the Ni dispersion and the reducibility of the promoted catalysts. The best feed rate which assures the optimal ratio between conversion and catalyst deactivation is 0.8 mL/min bio-ethanol. The addition of extra oxide (La2O3 and CeO2) to the support improves the ethanol conversion especially at 250 °C, but no significant effect on the acetic acid conversion was observed. At 250 °C the ethanol conversion is almost 90% for Ni/La2O3–Al2O3 and Ni/CeO2–Al2O3, but the acetic acid conversion is below 30% for all catalysts. At 350 °C both ethanol and acetic acid present maximum conversion. At this temperature the best hydrogen production is obtained for Ni/La2O3–Al2O3 due to better ethanol conversion and better selectivity for hydrogen formation. At 350 °C the promoted catalysts are stable for 4 h time on stream, different degrees of deactivation being obtained at lower temperatures.
This study evaluates the production of biodiesel and ethanol from spent coffee grounds (SCG). The extraction of oil from SCG, biodiesel production and ethanol production processes were studied. The liquid-to-solid ratio and temperature were evaluated in the ultrasound-assisted extraction of the oil from SCG. The highest yield (12%) was obtained using 4mLg(-1) liquid-to-solid ratio at 60°C for 45min. The process to produce biodiesel showed a yield of 97% into fatty acid methyl esters (FAME). The highest glucose yield (192mggSCG(-1)) was obtained by hydrolysis with 0.4molL(-1) sulfuric acid at 121°C for 15min. The hydrolysate was used as fermentation medium for ethanol production by Saccharomyces cerevisiae obtaining 19.0gL(-1) at 10h of process of ethanol with a yield of ethanol and productivity of 0.50gg(-1) and 1.90gL(-1)h(-1), respectively. Spent coffee grounds were considered a potential feedstock for biodiesel and ethanol production.
A practical process was developed for production of a high quality hydrolysate of waste newspaper that ensured its complete fermentability to bioethanol. After pretreatment with 0.1N NaOH for 12h and sequential acid and enzyme hydrolysis, 10.1g/L of glucose (50.5%), 1.38g/L of mannose (6.9%) and 0.28g/L of galactose (1.4%), a total of 11.76g/L of fermentable sugars was obtained, which accounts for 88.7% of saccharification efficiency. The Saccharomyces cerevisiae BCRC20271 showed excellent co-fermentability of glucose, mannose and galactose in hydrolysate of waste newspaper. After cultivation of the hydrolysate at 24°C in static culture for 48h, the final ethanol concentration of 5.72g/L (96% conversion efficiency) was produced. Overall, 1000kg of waste newspaper will produce 286kg (362L) of ethanol by the process developed, which reveals that waste newspaper has higher potential than many other lignocellulosic and seaweed feedstocks for bioethanol production.
The conversion of industrial paper sludge to ethanol was simulated using engineering process simulation software loaded with laboratory generated conversion data and financially analyzed. In one scenario, sludge is fractionated to remove ash, generating a higher concentration carbohydrate stream for separate hydrolysis and fermentation (SHF). In a second scenario, non-fractionated sludge is processed with only pH adjustment. Four primary sludges from mills producing either virgin or recycled paper were analyzed and the experimental conversion results used to inform the simulations. Financial analysis was conducted assuming ethanol wholesale price of US$ 0.608 per liter. The most profitable case was fractionated virgin sludge (from a virgin paper mill) to ethanol (F-VK1) with a net present value (NPV) of US$ 11.4 million, internal rate of return (IRR) of 28%, payback period of 4.4 years and minimum ethanol revenue (MER) of US$ 0.32 per liter. Risk analysis showed that the F-VK1 case obtained a near 100% probability of business success with both central and bearish (pessimistic) assumptions.
