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Bio-catalysis as a Green Approach for Industrial Waste Treatment

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Abstract

Since from the recent past, the attention of industrial wastes has grabbed the focus of the researchers toward designing and development of certain methods or processes in order to lessen the usage and the production of pollutants. With the knowledge of green chemistry, the catalysis using enzymes is the potential method for the production of industrial polymers at a high level without using hazardous reagents and thus curbing the pollution. Enzyme cofactors play a significant role in bio-catalysis since enzymes need them in order to catalyze significantly important reactions in organic synthesis. With the introduction and implementation of stringent processes to discharge waste into the environment, there is a need of the hour to develop alternative methods or processes to treat wastes. There exist large numbers of reported enzymes, which are mentioned in this chapter, from numerous microbes which are playing a major role in treating industrial wastes. Enzymes being specific in nature act and remove pollutants of recalcitrant nature via a certain process like precipitation and then transforming to some other products with certain changes in their characteristics. This results in increasing the susceptibility toward treatment in order to transform the waste into a value-added product. There are numerous unique applications of the catalytic activities, highlighted in the chapter for the proper understanding of the enzymes with the significance of their functions. Nowadays, it has become extensively important to use enzymes rather than hazardous chemicals so as to touch the demands of healthy, clean, and green technologies to protect our earth. This chapter highlights the importance of bio-catalytic reactions to treat various industrial wastes like the tobacco industry, pharmaceutical industry, textile industry, and dye industry with minimum invasiveness.

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There is a growing generation of biodegradable wastes from different human activities from industrial to agricultural including home and recreational activities. On the other hand, agricultural and horticultural activities require significant amounts of organic amendments and pesticides. In this framework, the present study evaluates the viability of soy fiber residue valorization as organic soil amendment with biopesticide properties through aerobic solid-state fermentation (SSF) in the presence of Bacillus thuringiensis (Bt). The experiments were performed first under sterile and non-sterile conditions at lab scale using 115 g of sample and controlled temperature (30 °C). Bt growth was successful in sterile conditions, obtaining 6.2 × 10(11) CFU g(-1) DM and 8.6 × 10(10) spores g(-1) DM after 6 days. Bt survived on solid culture under non-sterile conditions (3.8 × 10(9) CFU g(-1) DM and 1.3 × 10(8) spores g(-1) DM). Further, the valorization process was scaled-up to 10 L reactors (2300 g) under non-sterile conditions obtaining a final stabilized material with viable Bt cells and spores (9.5 × 10(7) CFU g(-1) DM and 1.1 × 10(8) spores g(-1) DM in average) after 9 days of SSF. These results confirm the possibility of managing biodegradable wastes by their transformation to a waste derived soil amendment with enhanced biopesticide effect, in comparison to traditional compost using a valuable and low-cost technique (SSF).
Article
Biodegradation of fat, oil, and grease (FOGs) plays an important role in wastewater management and water pollution control. However, many industrial food-processing and food restaurants generate FOG-containing wastewaters for which there is no acceptable technology for their pretreatment. To solve these problems, this study evaluated the feasibility of effective FOG-degrading microorganisms on the biodegradation of olive oil and FOG-containing wastewater. Twenty-two strains capable of degrading FOGs were isolated from five FOG-contaminated sites for the evaluation of their FOG degradation capabilities. Among twenty-two strains tested, the lipase-producing Pseudomonas sp. strain D2D3 was selected for actual FOG wastewater treatment. Its biodegrability was performed at 30°C and pH 8. The extent of FOG removal efficiency was varied for each FOG tested, being the highest for olive oil and animal fat (94.5% and 94.4%), and the lowest for safflower oil (62%). The addition of organic nitrogen sources such as yeast extract, soytone, and peptone enhanced the removal efficiency of FOGs, but the addition of the inorganic nitrogen nutrients such as NH4Cl and (NH4)2SO4 did not increase. The KH2PO4 sources in 0.25% to 0.5% concentrations showed more than 90% degrability. As a result, the main pathway for the oxidation of fatty acids results in the removal of two carbon atoms as acetyl-CoA with each reaction sequence: β-oxidation. Its lipase activity showed 38.5 U/g DCW using the optimal media after 9 h. Real wastewater and FOGs were used for determining the removal efficiency by using Pseudomonas sp. strain D2D3 bioadditive. The degradation by Pseudomonas sp. strain D2D3 was 41% higher than that of the naturally occurring bacteria. This result indicated that the use of isolated Pseudomonas sp. strain D2D3 in a bioaugmentating grease trap or other processes might possibly be sufficient to acclimate biological processes for degrading FOGs.
Article
A comparative study was carried out for proteases production using agroindustrial residues as substrate for solid state fermentation (SSF) of several fungal strains. High protease production was observed for most of the microorganisms studied, as well as very different biochemical characteristics, including activities at specific temperatures and a wide range of pH values. The enzymes produced were very different regarding optimum pH and they showed stability at 50 °C. Aspergillus oryzae showed stability at all pH values studied. Penicillium roquefortii and Aspergillus flavipes presented optimum activity at temperatures of 50 °C and 90 °C, respectively. Lyophilized protease from A. oryzae reached 1251.60 U/g and yield of 155010.66 U/kg of substrate. Therefore, the substrate as well as the microorganism strain can modify the biochemical character of the enzyme produced. The high protease activity and stability established plus the low cost of substrates, make these fungal proteases potential alternatives for the biotechnological industry.
Article
Redox-mediators such as syringaldehyde (SA) can improve laccase-catalyzed degradation of trace organic contaminants (TrOCs) but may increase effluent toxicity. The degradation performance of 14 phenolic and 17 non-phenolic TrOCs by a continuous flow enzymatic membrane reactor (EMR) at different TrOC and SA loadings was assessed. A specific emphasis was placed on the investigation of the toxicity of the enzyme (laccase), SA, TrOCs and the treated effluent. Batch tests demonstrated significant individual and interactive toxicity of the laccase and SA preparations. Reduced removal of resistant TrOCs by the EMR was observed for dosages over 50μg/L. SA addition at a concentration of 10μM significantly improved TrOC removal, but no removal improvement was observed at the elevated SA concentrations of 50 and 100μM. The treated effluent showed significant toxicity at SA concentrations beyond 10μM, providing further evidence that higher dosage of SA must be avoided.
Article
Chitosan beads were prepared, using glutaraldehyde as a crosslinking agent for the immobilization of soybean hull peroxidase (SBP). The activity of free and immobilized SBP was studied. The optimum pH was 6.0 for both the free and immobilized enzyme; however, enzyme activity became more dependent on the temperature after immobilization. This study evaluated the potential use of immobilized and free enzyme in the oxidation of caffeic acid, of synthetic phenolic solution (SPS) and of total phenolic compounds in coffee processing wastewater (CPW). Some factors, such as reaction time, amount of H2O2 and caffeic acid were evaluated, in order to determine the optimum conditions for enzyme performance. Both enzymes showed a potential in the removal of caffeic acid, SPS and CPW, and immobilized SBP had the highest oxidation performance. The immobilized enzyme showed a potential of 50% in the oxidation of caffeic acid after 4 consecutive cycles. Copyright © 2015. Published by Elsevier B.V.
Article
Immobilization process is to optimize the operational performance of an enzyme for industrial applications. So far different matrices have been described in the literature to improve the performance of the immobilized enzymes. With the advent of nanotechnology, the nanomaterials because of their unique physico-chemical properties constitute novel and interesting matrices for enzyme immobilization. The nanomaterials possess ideal characteristics to equilibrate principal factors which determine biocatalysts efficiency, including specific surface area, mass transfer resistance and effective enzyme loading. This review presents the current scenario and techniques in enzyme immobilization. An overview of the main methods used to combine proteins/enzymes with nanoparticles is given in the study. The advantages and disadvantages of nanoparticles as immobilization matrix are also discussed.
Article
Among six hundred yeast strains screened for their ability to produce lipase, Geotrichum sp was selected as the highest enzyme producer. The extracellular lipase was purified by ammonium sulfate fractionation and DEAE- Sephadex A-50 chromatography. The purified preparation showed higher activity within the pH range 7.5-9.0 and an optimum temperature of 45°C. The presence of isoenzymes with molecular weights of 52 Kdal and 57 Kdal was identified.
Article
The production of multienzyme solutions containing diverse hydrolytic enzymes has attracted increasing interest, because of their potential for simultaneously hydrolyzing different biological macromolecules. When these crude enzyme solutions are produced by solid-state fermentation (SSF) in agricultural byproducts, production costs are considerably lower than those of conventional submerged fermentation processes. Crude enzyme solutions containing mainly exo- and endoamylases, proteases, xylanases, and cellulases were produced under standardized procedures by means of SSF of babassu cake by Aspergillus awamori IOC-3914. Central composite designs were implemented and revealed optimal activities of the enzymes produced between pH 4.4-5.0 and 45-51 °C. Based on the application of a global desirability analysis on all the group of enzymes detected in the multienzyme solution, an overall optimal activity was observed at 53 °C and pH 4.7. These conditions were used for the separate hydrolysis of babassu cake and babassu flour, in order to evaluate the ability to simultaneously hydrolyze crude starch, cellulose, hemicelluloses, and protein. Under optimal global conditions, high levels of glucose, xylose, and free amino nitrogen (FAN) (up to 44, 19 and 0.75 g L−1, respectively) were obtained. Finally, the use of Tween 80 was found to activate both exo- and endoamylases (up to 50% increase).
Article
Vegetal origin agro-industrial wastes are seen as a problem since the beginning of the industrial processes; however, they are becoming attractive as raw material for numerous purposes such as active enzymes and in the molecules bioprospecting area. Moreover, it is difficult to understand what the studied residue is consisted of in studies on agro-industrial waste, since the wastes names and constituents may vary according to the used equipment, as for waste from orange and mango processing. Thus, defining a specific waste, including comparisons between botanical and industrial descriptions, can help understanding studies about wastes. The current review sought to contextualize such scenario by gathering definitions, relevant information and studies on agro-industrial wastes and byproducts, international enzymes market and recent studies on bioactive compounds. In this context, waste from orange and mango are interesting because the expression of theses fruits on the world market, moreover, the processing does not include steps which could disrupt these biomolecules.
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The synthesis of substituted pyridines has drawn the attention of many chemists due to their importance as building blocks for biologically active compounds and materials. This mini-review focuses on recent developments relating to the synthesis of substituted pyridines from pyridine N-oxides, along with their interesting mechanism aspects. New developments including alkenylation, alkynylation, alkylation, arylation, amination and cyanation are discussed.
Article
Ionic liquids (ILs), salts with melting points below 100 °C, represent a fascinating class of liquid materials typically characterized by an extremely low vapor pressure. Besides their application as new solvents or as electrolytes for electrochemical purposes, there are two important concepts of using ILs in catalysis: Liquid–liquid biphasic catalysis and IL thin film catalysis. Liquid–liquid biphasic catalysis enables either a very efficient manner to apply catalytic ILs, e.g. in Friedel–Crafts reactions, or to apply ionic transition metal catalyst solutions. In both cases, phase separation after reaction allows an easy separation of reaction products and catalyst re-use. One problem of liquid–liquid biphasic catalysis is mass transfer limitation. If the chemical reaction is much faster than the liquid–liquid mass transfer the latter limits the overall reaction rate. This problem is overcome in IL thin film catalysis where diffusion pathways and thus the characteristic time of diffusion are short. Here, Supported Ionic Liquid Phase (SILP) and Solid Catalyst with Ionic Liquid Layer (SCILL) are the two most important concepts. In both, a high surface area solid substrate is covered with a thin IL film, which contains either a homogeneously dissolved transition metal complex for SILP, or which modifies catalytically active surface sites at the support for SCILL. In each concept, interface phenomena play a very important role: These may concern the interface of an IL phase with an organic phase in the case of liquid–liquid biphasic catalysis. For IL thin film catalysis, the interfaces of the IL with the gas phase and with catalytic nanoparticles and/or support materials are of critical importance. It has recently been demonstrated that these interfaces and also the bulk of ILs can be investigated in great detail using surface science studies, which greatly contributed to the fundamental understanding of the catalytic properties of ILs and supported IL materials. Exemplary results concerning the IL/vacuum or IL/gas interface, the solubility and surface enrichment of dissolved metal complexes, the IL/support interface and the in situ monitoring of chemical reactions in ILs are presented. Graphical Abstract Important concepts in catalysis with ionic liquids are reviewed, including Supported Ionic Liquid Phase (SILP) and Solid Catalyst with Ionic Liquid Layer (SCILL), along with the detailed analysis of the relevant interfaces using surface science methods.