Francisco Manuel Gírio

• PhD in Biochemistry
• Head of Department at National Laboratory of Energy and Geology

Microbial lipids produced by yeasts from lignocellulosic biomass are a promising feedstock for the biodiesel industry, providing a renewable energy source as an alternative to traditional fossil fuels. This study investigated the potential of Yarrowia lipolytica W29 to produce lipid‐rich biomass from undetoxified sugar‐concentrated eucalyptus bark...

Fossil fuels drive global warming, necessitating renewable alternatives such as biomethane (or renewable natural gas). Biomethane, primarily produced through anaerobic digestion (AD), offers a cleaner energy solution but is limited by the slow AD process. Biomass gasification followed by syngas methanation has emerged as a faster alternative. This...

In the original publication [...]

Industrial liquid effluents (e.g., from fertilizer industry) and flue gas streams (e.g., CO2-rich, from cement industry) arise as an opportunity for waste valorization. Microalgae are suitable biomass for assimilating both effluents at the cultivation stage. Under a biorefinery concept, given the urge for energy transition in the aviation sector, t...

The study involves the use of commercial cellulase Cellic CTec2 in combination with two in-house xylanases, PxXyn10A (XynA), a recombinant purified enzyme from Paenibacillus xylanivorans A59, and a xylanase enzymatic extract from native Moesziomyces aphidis PYCC 5535T (MaPYCC 5535T), for the enzymatic hydrolysis of pretreated blue agave bagasse (BA...

The development of sustainable biofuels can help to reduce the reliance on fossil fuels and mitigate the impact of climate change. This study analyzes bioethanol production from agro-forestry residual biomass, namely eucalyptus residues and corn stover. The study includes process simulation using Aspen Plus software, followed by economic analysis a...

This study delves into the dynamics of hydrogen production, with a specific focus on biogas reforming (BGSMR) for hydrogen generation. It compares the environmental impact of this solution with hydrogen production from natural gas-steam reforming (NGSMR) and commercial electrolysis in the Portuguese context. Various metrics, including carbon footpr...

In recent years, polyhydroxyalkanoates (PHAs) have gained notoriety because of their desirable properties that include proven biodegradability, biocompatibility, and thermal stability, which make them suitable alternatives to fossil-based polymers. However, the widespread use of PHAs is still challenging because of their production costs, which are...

The world climate crisis has triggered the search for renewable energy sources. Oleaginous yeasts are a potential renewable source of biofuels. However, the yeast-derived biofuels cost is still non-competitive with the fossil fuel prices. To improve the sustainability of yeast-derived biofuels, it is necessary to valorize all yeast biomass fraction...

A methodology was developed to assess the allocation of different types of endogenous waste biomass to eight technologies for producing electricity, heat, biogas and advanced biofuels. It was based on the identification of key physicochemical parameters for each conversion process and the definition of limit values for each parameter, applied to tw...

In this work, microbial lipid production from non-detoxified Eucalyptus bark hydrolysate (EBH) with oleaginous xylose-utilizing Ashbya gossypii strains was explored. The best producing strain from a set of engineered strains was identified in synthetic media mimicking the composition of the non-detoxified EBH (SM), the lipid profile was characteriz...

Energy crops are industrial species (woody, perennial, and annual species, among others) that can generate biofuels, energy, and bioproducts. Due to their tolerance, there is an interest to grow energy crops in marginal/contaminated/degraded soils, avoiding Indirect Land Use Change (ILUC) burdens. Therefore, this study aims at the development and u...

Energy crops are industrial species (woody, perennial and annual species, algae, among others) that can generate biofuels, energy, and bioproducts. Due to their tolerance, there is an interest to grow energy crops in marginal, contaminated, and degraded soils, avoiding Indirect Land Use Change (ILUC) burdens. ArcGIS software was used as a Geographi...

Microalgae represent a promising solution in addressing the impacts associated with the current agricultural and manufacturing practices which are causing irreparable environmental damage. Microalgae have considerable biosynthetic potential, being a rich source of lipids, proteins, and high-value compounds. Under the scope of the H2020-BBI MULTI-ST...

Lytic polysaccharide monooxygenases (LPMOs) catalyze oxidative cleavage of crystalline polysaccharides such as cellulose and are crucial for the conversion of plant biomass in Nature and in industrial applications. Sunlight promotes microbial conversion of plant litter; this effect has been attributed to photochemical degradation of lignin, a major...

This work evaluated the effects of condensable syngas impurities on the cell viability and product distribution of Butyribacterium methylotrophicum in syngas fermentation. The condensates were collected during the gasification of two technical lignins derived from wheat straw (WST) and softwood (SW) at different temperatures and in the presence or...

Several pre-treatments are used to release sugars from lignocellulosic materials that are used to produce second-generation ethanol (2G). This study aimed to evaluate the kinetic release of glucose and xylose through the enzymatic and physical treatments of sugarcane bagasse and residual forest biomass, focusing on the ratio between hexose and pent...

Organosolv pre-treatments aiming to selectively remove and depolymerise lignin and hemicellulose and yield an easily digestible cellulose fraction are one of the potential options for industrial implementation within the biorefinery concept. However, the use of high temperatures and/or high catalyst concentrations is still hindering its wide adopti...

The Sustainable Value methodology was used to compare and rank eight combinations of waste biomass types and conversion technologies on a common assessment basis to produce energy, energy vectors and advanced biofuels. The studied combinations included agricultural and agro-industrial residues, slurries and effluents, pulp and paper mill sludge, pi...

Energy crops are dedicated cultures directed for biofuels, electricity, and heat production. Due to their tolerance to contaminated lands, they can alleviate and remediate land pollution by the disposal of toxic elements and polymetallic agents. Moreover, these crops are suitable to be exploited in marginal soils (e.g., saline), and, therefore, the...

Microalgae represent a promising solution to address the growing perception that current agricultural and manufacturing practices are causing irreparable environmental damage. Microalgae have a considerable biosynthetic potential and are a rich source of lipids, protein and high-value compounds (e.g. pigments). Despite these advantages they are und...

The increasing demand for greener and sustainable alternatives to fossil-derived fuels, chemicals, and materials has attracted huge attention to lignin, the largest renewable source of aromatic building blocks on earth. This natural polymer accounts for 15 to 40% of all lignocellulosic biomass. As such, in the pulp and paper industries, for example...

Biorefineries design, as for other industries, usually target the economy of scale approach, maximizing processing capacities to achieve economic viability. However, the installation of large-scale biorefineries has some drawbacks, namely their high capital costs and the difficulty to assure a proper supply of biomass at regional level. Small-scale...

Biomass pre-treatment is a key step in achieving the economic competitiveness of biomass conversion. In the present work, an imidazole pre-treatment process was performed and evaluated using wheat straw and eucalyptus residues as model feedstocks for agriculture and forest-origin biomasses, respectively. Results showed that imidazole is an efficien...

Hybrid bio-thermochemical based technologies have the potential to ensure greater feedstock flexibility for the production of bioenergy and bioproducts. This study focused on the bioconversion of syngas produced from low grade technical lignin to C2-/C4-carboxylic acids by Butyribacterium methylotrophicum. The effects of pH, medium supplementation...

Europe is committed to a new growth strategy with no net greenhouse gases emissions by 2050, where hydrogen has a clear role to play. Portugal's strategy for H2 sets public policies promoting an industry focused on the hydrogen value chain. Considering the production of green hydrogen from renewable sources is key, water electrolysis becomes a prio...

The yeast Rhodosporidium toruloides NCYC 921 was used for lipid production, using Miscanthus biomass hydrolysate as carbon source. The hydrolysate was obtained by enzymatic hydrolysis of Miscanthus biomass (at high solids loading) previously subjected to a hydrothermal pre-treatment. Afterwards R. toruloides was grown on Miscanthus sp. hydrolysate...

Assessment of water sources suitability using a sustainable value approach for green H2 produced from water electrolysis

Within the H2020 AMBITION project, innovative and energy efficient pre-treatment processes were developed in order to be integrated in a biomass processing improvement concept that would produce liquid streams of sugars and lignin derivatives for applications in bioenergy and added-value products. The objective of this work is to analyse the enviro...

This study evaluated the production of endoxylanases by Streptomyces malaysiensis AMT-3 in submerged fermentation using by-products of the food industry at 28ºC. In shake-flasks experiments, the highest endoxylanase activity of 45.8 U.mL-1 was observed within 6 days in a medium containing (w/v) 2.5% wheat bran and 1.2% corn steep liquor. The same c...

The main objective of the Portuguese project “CONVERTE-Biomass Potential for Energy” is to support the transition to a low-carbon economy, identifying biomass typologies in mainland Portugal, namely agri-forest waste, energy crops and microalgae. Therefore, the aim was to design and construct a georeferenced (mapping) database for mainland Portugal...

This work presents a comparative simulation study involving the techno‐economic and environmental assessment of lignocellulosic‐based small‐scale biorefineries, integrated with a piggery waste‐based anaerobic digestion platform (ADB), located in Portugal and Chile. Two main products are obtained: isobutene and xylo‐oligosaccharides (XOS). The biopr...

Energy crops are dedicated cultures directed to the production of energy in the form of biofuels, electricity or heat. However, those crops also present a dual purpose, since, due to their tolerance to contaminated soils, they are able to remediate and alleviate soil pollution derived from the disposal of polymetallic agents and other toxic element...

Lignin-rich residues are a side stream in advanced ethanol biorefineries and they are usually used for heat and power production. However, an alternative is the lignin valorisation by thermochemical and biochemical processes that might be economically more suitable. In this work lignin-rich residues were firstly thermochemical converted to syngas i...

This paper reports the use of lignin-rich residues from second generation bioethanol production, to produce syngas that can be applied in the gas fermentation process. Three gasification technologies at a different scale were considered in this study. Fixed bed updraft gasification of about 30 kg/h solid feed, bubbling fluidized bed gasification of...

Fossil fuels depletion and climate change, in addition to the current global energy demands require the search for suitable fossil substitutes (Abas et al., 2015). One way to overcome this issue is the development of biorefinery processes for the production of biofuels and bioproducts with lower Global Warming Potential. Studies have revealed that...

Ionic liquids have been recognised as interesting solvents applicable in efficient lignocellulosic biomass valorisation, especially in biomass fractionation into individual polymeric components or direct hydrolysis of some biomass fractions. Considering the chemical character of ionic liquids, two different approaches paved the way for the fraction...

Ionic liquids have been recognised as interesting solvents applicable in the efficient lignocellulosic biomass valorisation, especially in the biomass fractionation into individual polymeric components or direct hydrolysis some of biomass fractions. Considering the chemical character of ionic liquids, two different approaches, paved the way for a f...

Purpose: The use of bagasse and trash from sugarcane fields in ethanol production is supposed to increase the ethanol yield per hectare, to reduce the energy demand, greenhouse gas emissions, and other environmental impacts. In this article, different technological options of ethanol production are investigated and quantified looking at potential e...

A techno-economic assessment for the direct production of ethanol using a genetically-modified microalgae has been studied. It was considered two main scenarios for process modelling: i) bioenergy-driven microalgae plant, i.e., focused on the production of fuel-grade ethanol and biogas for CHP and, ii) biorefinery-driven microalgae plant, focused o...

The success of modern biorefineries, including those using starch-based feedstocks, should be based on versatile biomass supply chains and on the production of a wide spectrum of competitive bio-based products. This chapter summarizes the current knowledge of bio-based products obtained mainly from biochemical platforms from starch- and sugar-based...

Enzymes cost still constitutes one of the major barriers to commercial implementation of lignocellulosic ethanol. Therefore, search for more efficient and cost-effective enzymes is desirable. Given the market availability of efficient commercial cellulases, focus should be given to novel effective xylanases to boost hemicellulose conversion. In the...

Agro-industrial residues are presently underused and attractive renewable resources. Recently, there has been a great interest in its use as low-cost raw materials for the production of value-added compounds as microbial enzymes. Hemicelulases have been gaining increasing attention due to its wide biotechnological applications, especially in the bi...

Flow cytometry was used to evaluate the effect of initial ethanol concentrations on cyanobacterial strains of Synechocystis PCC 6803 [wild-type (WT), and ethanol producing recombinants (UL 004 and UL 030)] in batch cultures. Ethanol recombinants, containing one or two metabolically engineered cassettes, were designed towards the development of an e...

Climate change caused by the excessive use of non-renewable resources as a means of supporting the current society demands is forcing the development of circular economy models and social, economic and environmental balanced solutions. In Portugal, in recent decades, important progresses have been made on waste resources management practices in lin...

Climate change caused by the excessive use of non-renewable resources as a means of supporting the current society demands is forcing the development of circular economy models and social, economic and environmental balanced solutions. In Portugal, in recent decades, important progresses have been made on waste resources management practices in lin...

A process has previously been optimized for production of lactic acid from recycled paper sludge (RPS), the ultimate solid waste obtained in the wastewater treatment plant of a local paper recycling mill. In this work, both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes were improved un...

This policy-oriented opinion paper, which has taken the form of a Manifesto, is co-authored by scientists and engineers from Southern European Union countries that are presently experiencing deep and complex systemic crises: Portugal, Spain, Italy, Greece and Cyprus. With their Manifesto, the authors advocate the adoption of a new development model...

This chapter intends to give a brief overview of current conventional and advanced biomass-based biorefineries in the World. While the conventional biorefineries use mature and commercial technology , the advanced biorefineries (e.g., lignocellulosic-based biofuel biorefineries , microalgae-based biorefineries ) have different degrees of technology...

Production of lactic acid from recycled paper sludge by simultaneous saccharification and fermentation (SSF) has previously been implemented under a pulsed fed-batch mode. However, lactic acid concentrations above 58 g L⁻¹ inhibit cultivation of the Lactobacillus rhamnosus strain used. Thereby, the present work targeted process intensification by r...

Liquid hot water treatment, also commonly known as autohydrolysis, is one of the most promising and effective fractionation methods for the selective recovery of hemicelluloses in the liquid stream. Lignin can be recovered in the solid phase, with minor losses, as well as cellulose, whose enzymatic digestibility is enhanced.This chapter revises the...

Eucalyptus residues, wheat straw, and olive tree pruning are lignocellulosic materials largely available in Southern Europe and have high potential to be used solely or in mixtures in sugar-based biorefineries for the production of biofuels and other bio-based products. Enzymatic hydrolysis of cellulose is commonly used in this context, but its hig...

The steam explosion was carried out in the absence (autohydrolysis) and presence of phosphoric acid to evaluate the effects of temperature (180 and 210 °C), acid concentration (0 and 19 mg g-1 , dry basis) and pretreatment time (5 and 10 min) on the structure and reactivity of sugarcane bagasse. Glucan recovery was used as the main response factor...

Background The production of ethanol and other fuels and chemicals from lignocellulosic materials is dependent of efficient xylose conversion. Xylose fermentation capacity in yeasts is usually linked to xylose reductase (XR) accepting NADH as cofactor. The XR from Scheffersomycesstipitis, which is able to use NADH as cofactor but still prefers NADP...

This work evaluates the environmental performance of using pulp and paper sludge as feedstock for the production of second generation ethanol. An ethanol plant for converting 5400tons of dry sludge/year was modelled and evaluated using a cradle-to-gate life cycle assessment approach. The sludge is a burden for pulp and paper mills that is mainly di...

Production of drop-in bioethanol from microalgae: an energy-driven approach under a biorefinery concept, 3CIAB, Chile, November 2015

Autotrophic microalgae are photosynthetic organisms that undergo the conversion of light into chemical energy as a form of a wide range of organic compounds through its photosynthetic machinery. The cultivation of microalgae brings environmental advantages, bearing in mind the capability of nutrient recycling in wastewaters together with the fixati...

Gasification of spent lignin pellets was used to obtain a gas suitable for energy production. Spent lignin was obtained from second-generation cellulosic ethanol demo plant using wheat straw as feedstock. Gasification of lignin did not give rise to any feeding problems, thus no significant changes were needed in the existing gasification installati...

NOVELTY - Fractionation of lignocellulosic biomass involves recovering cellulose, hemicellulose and lignin. The fractionation is achieved after a heat processing of biomass in presence of ionic liquid. The obtained solution is then subjected to processing with an anti-solvent to obtain a material that is rich in polysaccharides and a liquid fractio...

In this study, yeasts associated with lignocellulosic materials in Brazil, including decaying wood and sugarcane bagasse, were isolated, and their ability to produce xylanolytic enzymes was investigated. A total of 358 yeast isolates were obtained, with 198 strains isolated from decaying wood and 160 strains isolated from decaying sugarcane bagasse...

Concentrated sludge generated in large amounts by the wastewater treatment facilities of recycling paper plants raises a serious disposal problem requiring urgent solution. This recycled paper sludge (RPS) is an industrial waste with high polysaccharide content. As previously demonstrated, cellulosic and hemicellulosic fractions of RPS can be compl...

A new approach to the extraction of bioactive phenolic compounds from carob kibbles has been proposed. Carob pulp kibbles, a by-product of the carob bean gum production, were subject to supercritical fluid extraction (SFE) and to ultrasound assisted (UAE) and conventional solid-liquid extractions with two different solvent systems (100% H2O and 70%...

The production of oligosaccharides (OS) by olive tree pruning autohydrolysis in the range 170–230 °C was studied. The best results in terms of maximum yield of OS along with a low amount of byproducts were obtained at 180 °C. After purification by preparative gel filtration chromatography a range of OS-fractions with average degree of polymerisatio...

Arundo donax is an energy-crop with a high potential for the production of added-value products and bioenergy. The hemicellulose fraction of Arundo donax was selectively hydrolyzed with diluted sulfuric acid in order to obtain a fermentable hydrolyzate that was used to produce a culture medium for xylitol production by the yeast Debaryomyces hansen...

Hemicelluloses hold a great promise for the production of added-value compounds in the biorefinery framework. Specifically, the xylan-rich hemicelluloses from hardwoods and agro-industrial residues present themselves as effective feedstock choices for the biotechnological production of xylitol. This paper reviews the various hemicellulose structure...

In the biochemical pathway of lignocellulosics conversion into fuels, a significant portion of biomass cannot be hydrolysed to fermentable sugars and remains as recalcitrant waste substrate. In terms of product yield, this residual biomass represents renewable feedstock that is being wasted, which contradicts the target of 100% feedstock utilisatio...

Detailed kinetic and physiological characterisation of eight mannitol-producing lactic acid bacteria, Leuconostoc citreum ATCC 49370, L. mesenteroides subsp. cremoris ATCC19254, L. mesenteroides subsp. dextranicum ATCC 19255, L. ficulneum NRRL B-23447, L. fructosum NRRL B-2041, L. lactis ATCC 19256, Lactobacillus intermedius NRRL 3692 and Lb. reute...

The industrial use of starter cultures containing a consortium of different strains from the same species is nowadays seen as a possible strategy to enhance the organoleptic complexity of wines. To assess the relative contribution of each strain to the final product it is essential to quantify population evolution during the wine fermentation proce...

The nature of the toxic compounds produced by Saccharomyces cerevisiae CCMI 885 that induce the early death of Hanseniaspora guilliermondii during mixed fermentations, as well as their ability to inhibit the growth of other non-Saccharomyces wine-related strains, was investigated. The killing effect of mixed supernatants towards H. guilliermondii w...

Hemicelluloses currently represent the largest polysaccharide fraction wasted in most cellulosic ethanol pilot and demonstration plants around the world. The reasons are based on the hemicelluloses heterogeneous polymeric nature and their low fermentability by the most common industrial microbial strains. This paper will review, in a "from field to...

A process for biological upgrading of recycled paper sludge (RPS) was developed based on the enzymatic hydrolysis of major sludge components (cellulose and xylan) with commercial enzymes and fermentation of the resulting sugars into ethanol or lactic acid with adequate microbial strains. The process was implemented performing both steps sequentiall...

The dilute acid posthydrolysis of wheat straw hemicellulosic oligosaccharides obtained by autohydrolysis was evaluated. An empirical model was used to describe the effect of catalyst concentration (sulfuric acid, 0.1-4% w/w) and reaction time (0-60 min) based on data from a Doehlert experimental design. Catalyst concentration is the main variable i...

Wheat straw was subjected to autohydrolysis treatments in order to selectively hydrolyze the hemicellulose fraction. The effects of temperature (150–240°C) and non-isothermal reaction time on the composition of both liquid and solid phases were evaluated and interpreted using the severity factor (log R 0). The operational conditions leading to the...

The objective of this study was to compare the in vitro fermentability of xylo-oligosaccharides (XOS) with different degrees of polymerisation (DP) by the intestinal digesta collected in three distinct intestinal sections of the porcine intestinal tract: ileum, caecum, and distal colon. The studied oligosaccharides included commercial short-chain X...