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Xylan is a renewable polysaccharide, readily available in agricultural and forestry residues. It can be hydrolyzed to produce xylooligosaccharides (XOS) with prebiotic activity and xylose, a precursor for several industrial chemicals. Enzymatic hydrolysis of xylan in the lignocellulosic biomass to obtain xylose and XOS requires a pretreatment to facilitate xylanase activity. In this study, organosolv was evaluated for the delignification of corncob while retaining xylan in the pretreated biomass. The treatment at 170 °C for 1 h with 70% ethanol provided 50% lignin removal and 81% xylan recovery. Increasing temperatures and decreasing ethanol fractions decreased the pH and the xylan recovery. Loss of xylan in the organosolv at 190 °C and in the liquid hot water treatment could be prevented by the addition of 100 mM MgO, without compromising lignin removal. Pretreated corncob was suspended in citrate buffer and hydrolyzed by commercial xylanases. Accellerase XY (250 U/ml) at pH 5.5 and 55 °C and Econase XT (0.6 U/ml) at pH 6.0 and 70 °C provided around 65% xylan digestibility and generated xylose (9.8 g/l) and XOS (10.9 g/l), respectively. This approach could decrease xylan loss and degradation in the pretreatment step and yield clear hydrolysates composed of essentially xylose or XOS. Lignocellulosic biorefineries can benefit from the efficient utilization of xylan, increasing sustainability.

As an industrial energy plant, the whole parts of the sunflower crop were used for biofuel production through a biorefinery approach. Two scenarios were suggested for this biorefinery, i.e., using all parts of the crop separately and the whole residues as a mixture. The oil extracted from seeds was applied for biodiesel production through transesterification using a 6:1 methanol to oil molar ratio with 0.7% catalyst at 50 °C for 65 min. The process resulted in a 96.2% biodiesel yield with a heating value of 41.6 MJ/kg, corresponding to 84 kg biodiesel per ton of sunflower crop and 108.8 L gasoline-equivalent. Three physiochemical pretreatments were employed for structural modification of lignocellulosic residues, and the solid and liquid phases of the pretreatments were anaerobically digested for biomethane production. The effects of hot water (180 °C, 1 h), concentrated phosphoric acid (50 °C, 1 h, 85%), and sodium carbonate (142 °C, 18 min, 4%) pretreatments on composition, crystallinity, morphology, and biogas production of solid samples were evaluated. The highest methane yield of solid fractions was obtained from samples treated with phosphoric acid, and the seed cake showed the maximum yield of 342.7 N mL/g VS among all parts. Furthermore, the liquid phase of the hot water and alkaline pretreatments produced a high amount of biomethane, contrary to the acidic pretreatment. The overall mass balance showed that 11095.0 MJ/t energy (containing 346.7 L gasoline energy) was produced through the optimum biorefinery, where the untreated mixture and seed cake were used for biomethane production and the extracted oil for biodiesel production.

International audience; This paper aims to investigate the effect of extrusion at high solid loading on corn stover (CS) properties and its enzymatic hydrolysis. This biomass was extruded under different screw speeds and different solid loadings and the impact of these parameters on physicochemical properties was evaluated. It was found that lignocellulosic components were not significantly affected by the pretreatment, while surface area increased with solid loading and rotation speed. Different enzyme cocktails were used for the enzymatic hydrolysis of extruded and untreated CS. Overall, mild twin-extrusion enhanced the enzymatic hydrolysis of corn stover through an increase in glucose and xylose yields by 134-212% and 214-294% respectively when using T. longibrachiatum cellulase. The highest sugar content was obtained from CS extruded under 400 g total solids (TS) per liter and 200 rpm. The energy efficiency of the pretreatment was also assessed and was found to be maximal at 400 gTS/L and 200 rpm.

10 páginas.- 5 figuras.- 2 tablas.- 50 referencias.- The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acssuschemeng.2c01274, Innovative schemes for lignocellulosic biomass refining could optimize the chemical use and biomass conversion efficiency, providing diversified biorefinery products. A new biorefinery scheme used mild alkaline-sulfite chemithermomechanical processing to pretreat sugarcane bagasse, producing highly digestible solids and diluted lignosulfonates in the black pretreatment liquor. Most of the glucan and xylan contained in the pretreated solids were converted into monosaccharides by saccharification with commercial enzymes. The undigested biomass solids remaining from the saccharification process were recycled with the existing alkaline-sulfite black pretreatment liquor. The optimized reaction conditions (159 degrees C and 13% NaOH amendment in the liquor) enhanced the lignosulfonate concentration from 7.1 +/- 0.3 to 33.5 +/- 0.7 g/L. Mass balance for the process indicates that most of the original sugarcane bagasse lignin were split into lignosulfonates contained in the resulfonation liquor (57.3%) and in the enzymatic hydrolysate (16.2%). 2D-NMR analysis of a lignosulfonate fraction recovered by ultrafiltration confirmed that approximately 9-10% of all beta-O-4' alkyl-aryl ether substructures were alpha-sulfonated. The combined chemical characteristics of the prepared lignosulfonate suggested its suitability for use in several lignosulfonate applications., This work was supported by FAPESP (grant number 2019/25867-3), CNPq (grant number 308570/2017-0), and Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES)-Finance Code 001. J.R. and J.C.d.R. were funded by MCIN/AEI/10.13039/501100011033, by "ERDF A way of making Europe" (project PID2020-118968RB-I00), and by the Regional Andalusian Government, Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades/FEDER (project P20-00017).

Biorefinery is pivotal to the sustainability of modern chemical industry. However, since biomass is oxygen-enriched, new and green chemical strategies are required for expanding the biomass derived chemical space. In this work, synthesis of natural products dihydrocapsaicin and dihydrocapsiate was achieved exclusively from lignocellulosic platform chemicals. Natural products dihydrocapsaicin and dihydrocapsiate were synthesized exclusively from lignocellulosic platform chemicals, using furfural (from hemicellulose) and methyl isopropyl ketone (from cellulose) through aldol condensation-hydrolysis-hydrodeoxygenation to synthesize 8-methylnonanoic acid and then combined with vanillin derivates (from lignin). This synthesis demonstrates the feasibility of constructing natural products entirely from renewable biomass platform through green processes. The utilization of inherent functional groups of biomass demonstrates their potential to open up chemical space.

5 figures, 7 tables.-- Supplementary information available., The acid-free hydrothermal microwave–assisted selective scissoring (Hymass concept) of cellulosic substrates is gaining keen interest in the field of materials science. Besides, implementing catalytic methodologies to upgrade side streams produced during this process could contribute to better, holistic utilisation of the starting feedstock. This work depicts a zero-waste biorefinery concept based on cellulose defibrillation from almond hulls using various hydrotreatment technologies (hydrogenation and hydrodeoxygenation) for downstream processing on a ruthenium catalyst. Therein, the hemicellulose separated from the biomass preconditioning step was converted into sugar alcohols and/or marketable polyols with a relatively high yield (47.4%) by hydrolytic hydrogenation (437 K, 3h, 5.0 MPa H2). Meanwhile, a family of bioactive compounds (3-hydroxypyridines) could be directly extracted from the hydrolysate stream derived from microwave digestion, along with an energy carrier that was chemically stabilised (503 K, 60 min, 4.0 MPa H2) to obtain fuel additives (diethyl succinic acid, DES) and/or fuel intermediates., The authors are grateful for the financial support from the Spanish Ministry of Economy and Competitiveness (MINECO, Project ENE2017-83854-R) and the I+D+i project PID2020-115053RB-I00, funded by MCIN/AEI/10.13039/501100011033. J.R. is grateful to the Spanish Ministry of Science, Innovation and Universities for the Juan de la Cierva Incorporación (JdC-I) fellowship (Grant Number: IJC2018-037110-I) awarded.

Microbial production of 2,3-butanediol (BDO) has received considerable attention as a promising alternate to fossil-derived BDO. In our previous work, BDO concentration >100 g/L was accumulated using brewer’s spent grain (BSG) via microbial routes which was followed by techno-economic analysis of the bioprocess. In the present work, a life cycle assessment (LCA) was conducted for BDO production from the fermentation of BSG to identify the associated environmental impacts. The LCA was based on an industrial-scale biorefinery processing of 100 metric tons BSG per day modeled using ASPEN plus integrated with pinch technology, a tool for achieving maximum thermal efficiency and heat recovery from the process. For the cradle-to-gate LCA, the functional unit of 1 kg of BDO production was selected. One-hundred-year global warming potential of 7.25 kg CO2/kg BDO was estimated while including biogenic carbon emission. The pretreatment stage followed by the cultivation and fermentation contributed to the maximum adverse impacts. Sensitivity analysis revealed that a reduction in electricity consumption and transportation and an increase in BDO yield could reduce the adverse impacts associated with microbial BDO production.

In the framework of a sustainable marine bioeconomy, the present work describes an advanced, eco-friendly, fully integrated biorefinery process for marine Ulva fasciata macroalgae. That would serve as a solution for ecosystem bioremediation, an effective utilization of marine macroalgal resources, and a new initiative to promote a green and low-carbon economy. Ulva fasciata biomass can be utilized as an organic fertilizer with total N, P2O5, and K2O contents of 3.17% and a C/N ratio of 11.71. It can also be used as a solid biofuel with a sufficient calorific value of 15.19 MJ/kg. It has high carbohydrate content and low lignin content of approximately 44.85% and 1.5%, respectively, which recommend its applicability in bioethanol and biobutanol production. Its protein, fiber, lipid, and ash contents of approximately 13.13%, 9.9%, 3.27%, and 21%, respectively with relatively high concentrations of omega-3 fatty acids (n-3 PUFAs) and omega-9 fatty acids (n-9 MUFAs) and relatively low omega-6 fatty acids (n-6 PUFAs) and a n-6/n-3 ratio of 0.13 also recommend its applicability as food additives and animal feeders. Moreover, the suggested sequential zero-waste biomass residue process yielded 34.89% mineral-rich water extract (MRWE), 2.61% chlorophylla,b, 0.41% carotenoids, 12.55% starch, 3.27% lipids, 22.24% ulvan, 13.37% proteins, and 10.66% cellulose of Ulva fasciata dry weight. The efficient biocidal activity of extracted ulvan against pathogenic microorganisms and sulfate-reducing bacteria recommends its application for medical purposes, water densification, and mitigation of microbially induced corrosion in the oil and gas industry.

Decarbonization of the aviation sector relies on deployment of sustainable aviation fuels (SAF) at commercial scale. Hydrothermal liquefaction (HTL) has been recognized as a promising technology to help supply the increasing projected SAF demand. High availability of agro-industrial residues, combined with a well-established biorefinery system, makes the sugarcane industry in Brazil a good option for HTL technology deployment. Moreover, challenges regarding the economic feasibility of SAF from HTL could be partially addressed by the RenovaBio policy, a market-driven incentive mechanism of carbon credits implemented in Brazil. This study investigated both the techno-economic and life cycle assessment of SAF production from sugarcane lignocellulosic residues, considering HTL integrated to a first-generation ethanol distillery and a HTL stand-alone facility. The evaluated scenarios showed great climate mitigation potential, reaching a reduction of up to 73–82% when compared to fossil jet fuel. The minimum fuel selling price of SAF at 15.4 USD/GJ indicated potential of economic competitiveness with fossil jet fuel in the best integrated scenario. The economic benefits obtained from carbon credits are not enough to enable feasibility of HTL in the stand-alone scenarios, even with carbon prices projected at 125 USD/tonne CO2-eq avoided.

Pinus pinea nuts are commercial relevant Mediterranean edible forest nuts, with an increasing production and market value, whose industrial processing yields a lignocellulosic by-product, the pine nut shells, currently only used for combustion. Little research has been done on pine nut shells that could support a value-added application for this residue. This work studies for the first time the production of oligosaccharides by autohydrosis, and aims at an integrated upgrade within the biorefinery framework. Autohydrolysis was explored in the temperature range between 150 and 230 °C (corresponding to severity factors 2.13–4.63). Oligosaccharides, mainly xylo-oligosaccharides (95% of the total), were the key soluble products, reaching 28.7 g/100 g of xylan of the feedstock at the optimal conditions (log R0 4.01). Other products were monosaccharides and phenolic compounds that reached 7.8 and 4.7 g/L, respectively, under the most severe conditions. The stability of the oligosaccharides at different temperatures (room, 37 °C and 100 °C) and pH (between 1 and 11) grant them significant market potential in the food and pharma sectors. The pre-treated pine nut shells by autohydrolysis presented an improved, although low, enzymatic digestibility (14%), and an improved high-heating value, therefore advising their further valorization by thermochemical pathways.

Lignocellulosic biomass generated from different sectors (agriculture, forestry, industrial) act as biorefinery precursor for production of second-generation (2G) bioethanol and other biochemicals. The integration of various conversion techniques on a single platform under biorefinery approach for production of biofuel and industrially important chemicals from LCB is gaining interest worldwide. The waste generated on utilization of bio-resources is almost negligible or zero in a biorefinery along with reduced greenhouse gas emissions, which supports the circular bioeconomy concept. The economic viability of a lignocellulosic biorefinery depends upon the efficient utilization of three major components of LCB—cellulose, hemicellulose and lignin. The heterogeneous structure and recalcitrant nature of LCB is main obstacle in its valorization into bioethanol and other value-added products. The success of bioconversion process depends upon methods used during pre-treatment, hydrolysis and fermentation processes. The cost involved in each step of the bioconversion process affects the viability of cellulosic ethanol. The lignocellulose biorefinery has ample scope, but much-focused research is required to fully utilize major parts of lignocellulosic biomass with zero wastage. The present review entails lignocellulosic biomass valorization for ethanol production, along with different steps involved in its production. Various value-added products produced from LCB components were also discussed. Recent technological advances and significant challenges in bioethanol production are also highlighted in addition to future perspectives. Graphical abstract

The aqueous phase reforming (APR) is a catalytic reaction able to produce hydrogen from oxygenated compounds. The catalytic system plays a pivotal role to permit high conversion of the substrate, high selectivity towards hydrogen, and stability in the view of an industrial application. These figures of merit depend on several strategies taken by the researchers to properly design the catalyst, like the preparation method, the choice of the active metal together with possible promoters, the type of the support and so on. The available literature reports several studies where these parameters are evaluated and discussed. In this review, they were critically examined with the aim of finding correlations between the properties of the catalyst and the activity, selectivity and stability for the APR of carbon-laden water fractions. Both theoretical and experimental works have been included in the literature survey. When available, studies with the use of in-situ techniques allowed to increase the understanding of the catalytic phenomena involved in the reaction. Great attention was also reported to recently published works, so that the review could present the most up-to-date developments in the field. The most important outcomes regarding each parameter have been highlighted; moreover, the synergy among each of them has been pointed out, together with the trade-off that the researcher has to deal with in the pursuit of the optimum catalyst.

Microbial electrosynthesis (MES) for bioelectro carbon dioxide (CO2) recycling is an interesting and sustainable opportunity to exploit off gases from industrial facilities and convert them into valuable energy sources. In the present study, a two-step process based on coupling a bioelectrochemical system (BES) and heterotrophic microalgae Auxenochlorella protothecoides is proposed to convert carbon dioxide into a biodiesel compatible oil. The MES effluent was further processed in a heterotrophic microalgae batch reactor, where the acetate previously synthesized from CO2 was converted into bio-oil in a subsequent, extraction-free step. Two MES reactors were operated in batch mode at an applied cathodic potential of 0.8 V vs. SHE (standard hydrogen electrode) for 95 days. The system reached a concentration of up to 13 g L 1 of acetate (at a maximum production rate of 0.29 g L 1 d 1). Microbial community analysis revealed the presence of Clostridium spp. in both reactors. In a second stage, the effluent from the biocathode was transferred to microalgae reactors containing A. protothecoides to assess oil production. The bio-oil content was up to 22% w/w (dry weight), sufficient to further explore the feasibility of microalgae-to-oil recovery in the future. According to our estimations, 7.59 kg CO2 can be converted into 1 kg acetate, which can be used to grow heterotrophically 1.11 kg dry algae; an overall balance of 0.03 kg bio-oil produced per kg CO2 captured was assessed. The oil obtained can be further processed to produce a biodiesel compatible with EU requirements for biofuels This research was funded by the Spanish Ministry of Science through the grant RTI2018-098360-B-I00 and the Agency for Business Competitiveness of the Government of Catalonia (ACCIO) through the DigesTake Project (COMRDI16-1-0061). E. ´ P.-V. is grateful for the Research Training grant from the University of Girona (IFUdG2018/52). S. P. is a Serra Hunter ´ Fellow (UdG-AG-575) and acknowledges the funding from the ICREA Acad`emia award. LEQUiA and Ecoaqua have been recognized as consolidated research groups by the Catalan Government with codes 2017-SGR-1552 and 2017SGR-548, respectively

In recent times, biohydrogen production from microalgal feedstock has garnered considerable research interests to sustainably replace the fossil fuels. The present work adapted an integrated approach of utilizing deoiled Scenedesmus obliquus biomass as feedstock for biohydrogen production and valorization of dark fermentation (DF) effluent via biomethanation. The microalgae was cultivated under different CO2 concentration. CO2-air sparging of 5% v/v supported maximum microalgal growth and carbohydrate production with CO2 fixation ability of 727.7 mg L−1 d−1. Thereafter, lipid present in microalgae was extracted for biodiesel production and the deoiled microalgal biomass (DMB) was subjected to different pretreatment techniques to maximize the carbohydrate recovery and biohydrogen yield. Steam heating (121 °C) in coherence with H2SO4 (0.5 N) documented highest carbohydrate recovery of 87.5%. DF of acid-thermal pretreated DMB resulted in maximum H2 yield of 97.6 mL g−1 VS which was almost 10 times higher as compared to untreated DMB (9.8 mL g−1 VS). Subsequent utilization of DF effluent in biomethanation process resulted in cumulative methane production of 1060 mL L−1. The total substrate energy recovered from integrated biofuel production system was 30%. The present study envisages a microalgal biorefinery to produce biohydrogen via DF coupled with concomitant CO2 sequestration.

A pretreatment process is a preliminary stage to alter the recalcitrant structure of lignocellulosic biomass for enhancing its digestibility. An evaluation of the energy consumption and the environmental restrictions of the pretreatment step is required to develop a feasible eco-friendly process for industrial implementation. In this study, a combined alkaline-mechanical fractionation of rice straw for fermentable sugar (FS) production was developed with the objectives of i) evaluating energy efficiency and ii) addressing the sustainability of technology. The maximum fermentable sugar production was 0.54 kg/kg rice straw with an enzymatic hydrolysis efficiency of 97.34%. Furthermore, the results indicated that the pretreatment by 5% NaOH followed by mechanical size reduction provided the highest energy efficiency of 0.35 kg of FS/kWh with 94.44% glucose recovery, which also provided the lowest waste generation of less than 0.1 kg of waste/kg FS. These experimental results suggest that the combined alkaline-mechanical fractionation could effectively increase total FS yields and could be a promising pretreatment technology for an eco-friendly and sustainable pretreatment process integrated into a biorefinery platform.

The increasingly severe environmental pollution and energy shortage issues have demanded the production of renewable and sustainable biofuels to replace conventional fossil fuels. Lignocellulosic (LC) biomass as an abundant feedstock for second-generation biofuel production can help overcome the shortcomings of first-generation biofuels related to the “food versus fuel” debate and feedstock availability. Embracing the “circular bioeconomy” concept, an integrated biorefinery platform of LC biomass can be performed by employing different conversion technologies to obtain multiple valuable products. This review provides an overview of the principles and applications of thermochemical processes (pyrolysis, torrefaction, hydrothermal liquefaction, and gasification) and biochemical processes (pretreatment technologies, enzyme hydrolysis, biochemical conversion processes) involved in LC biomass biorefinery for potential biofuel applications. The engineering perspective of LC biofuel production on separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), simultaneous saccharification and co-fermentation (SSCF), and consolidated bioprocessing (CBP) were also discussed.

The present study demonstrates the feasibility of a two-phase biorefinery process applied to waste substrates producing ethanol rich effluents. The process includes a dark fermentation step followed by photo fermentation and it is able to optimize hydrogen production from waste biomass. The study was conducted using winery wastewater as feedstock. The results indicate that no additional treatments are required when an appropriate dilution of the initial waste is applied. Microbial consortia contained in the winery wastewater promoted a fermentative ethanol pathway. The ethanol rich effluent was converted into hydrogen by phototrophic microorganisms. Despite the presence of inhibiting compounds, the adoption of a mixed phototrophic culture allowed to obtain good results in terms of hydrogen production. Specifically, up to 310 mLH2 gCODconsumed−1 were obtained in the photo fermentative stage. The effectiveness of ethanol rich dark fermentation effluents for hydrogen production enhancement was demonstrated. Noteworthy, polyhydroxybutyrate was also produced during the experiments. The work faces two of the major challenges in the sequential dark fermentation and photo fermentation technology applied to real waste substrates: the minimization of pre-treatments and the enhancement of the hydrogen production yields using ethanol rich DFEs.

Over the last few years, a paradigm shift has emerged towards a circular economy that seeks to return to the process as many material/energy flows as possible to increase the sustainability of products, reducing waste and pollution. The citrus industry is not an exception hence one way to apply this approach is through the re-use of certain outflows to produce bioproducts and bioenergy. The objectives of this work are, first, to present the environmental profile of lemons and derivatives in Argentina through the Life Cycle Assessment methodology, and second, to unveil environmental implications of shifting from traditional industries to biorefineries which apply circular economy principles. To do that, the current production scheme for manufacturing essential oil, concentrated juices and dehydrated peel is studied (baseline), to then consider new products, i.e., ethanol, limonene and biogas, through several scenarios with different degrees of biogas recirculation. We find that for lemon production, agrochemicals represent more than 60% in eleven of the twelve impact categories. For processed products, agriculture contributes with more than 50% in all the categories, followed by natural gas and electricity consumption. It also results that adding value to wastes and implementing circular economy strategies do not ensure a better environmental performance of the system. When comparing the current situation with biorefinery schemes, the most promising scenario is the one in which all the biogas is used to produce electricity, causing the least impact in eight of the twelve categories analyzed.

A sustainable and integrated biorefinery strategy was achieved by a facile biphasic system, ferric trichloride (FeCl3) solution assisted by methyl isobutyl ketone (MIBK), yielding multiple products: furfural, sugars, and lignin nano-particles simultaneously. For the highest yield of furfural, the conditions were optimized resulting in 75.55% and over 69.38% of the yields from xylose and some typical biomasses respectively. Both the catalyst and MIBK can be recycled. Eucalyptus was lucubrated on the valorizations of three major-components with 75.18% of furfural yield, 97.54% of cellulase digestibility from the residue and lignin nano-particles. Meanwhile, the regularities of biomass degradation under this biphasic system were summarized as well as high digestibility which was resulted by hemicellulose and lignin removal in cooperation with the amount of the cellulase binding sites. Based on the proposed biorefinery strategy, 65.82% of the initial mass can be valorized into high-value end-products.

Cheese whey is the major by-product of the dairy industry, and its disposal constitutes an environmental concern. The production of cheese whey has been increasing, with 190 million tonnes per year being produced nowadays. Therefore, it is emergent to consider different routes for cheese whey utilization. The great nutritional value of cheese whey turns it into an attractive substrate for biotechnological applications. Currently, cheese whey processing includes a protein fractionating step that originates the permeate, a lactose-reach stream further used for valorisation. In the last decades, yeast fermentation has brought several advances to the search for biorefinery alternatives. From the plethora of value-added products that can be obtained from cheese whey, ethanol is the most extensively explored since it is the alternative biofuel most used worldwide. Thus, this review focuses on the different strategies for ethanol production from cheese whey using yeasts as promising biological systems, including its integration in lignocellulosic biorefineries. These valorisation routes encompass the improvement of the fermentation process as well as metabolic engineering techniques for the introduction of heterologous pathways, resorting mainly to Kluyveromyces sp. and Saccharomyces cerevisiae strains. The solutions and challenges of the several strategies will be unveiled and explored in this review., This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020; the Ph.D. grants SFRH/BD/130739/2017 and SFRH/BD/132717/2017 to CEC and SLB, respectively., info:eu-repo/semantics/publishedVersion

Coffee, as one of the most consumed beverages, generates a wide variety of waste materials that can be used as biofuels and bio-products. Conventional pyrolysis can be used in rural areas, improving the circular bioeconomy of these places. In this work, the characterization and slow pyrolysis of specialty coffee residues, coffee silverskin (CSS), and spent coffee (SC) were conducted at temperatures from 300 to 600 °C. Physico-chemical and thermal analysis were carried out. In addition, the quantification of individual compounds as acetic, formic, and levulinic acids, caffeine, and other minor compounds was performed. The results indicate the differences between both waste materials in the obtained pyrolysis fractions. The biochar fraction for SC is lower at all temperatures and the liquid fraction higher, reaching maximum values of 62 wt.% in the liquid at 600 °C compared to 47% in CSS. The higher yield in the liquid fraction of SC corresponds to the higher contents of hemicellulose and extractives and the lower ash content. The calculated calorific value for the pyrolysis solid fractions reaches 21.93 MJ/kg in CSS and 26.45 MJ/kg in SC. Finally, biorefinery options of major components of the liquid fraction were also presented. This research was funded by EUROPEAN COMMISSION, Marie Sklodowska-Curie Actions—RISE, grant number 101007733 (CELISE project), by Solvay, under projects 3399 and 3824, and the European LignoCOST Action, number CA17128 (https://lignocost.eu/, accessed on 1 February 2023).

Producción Científica, Harnessing fruit-vegetable waste (FVW) as a resource to produce hydrogen via dark fermentation (DF) embraces the circular economy concept. However, there is still a need to upgrade continuous FVW-DF bioprocessing to enhance hydrogen production rates (HPR). This study aims to investigate the influence of the hydraulic retention time (HRT) on the DF of FVW by mixed culture. A stirred tank reactor under continuous mesophilic conditions was operated for 47 days with HRT stepwise reductions from 24 to 6 h, leading to organic loading rates between 47 and 188 g volatile solids (VS)/L-d. The optimum HRT of 9 h resulted in an unprecedented HPR from FVW of 11.8 NL/L-d, with a hydrogen yield of 95.6 NmL/g VS fed. Based on an overarching inspection of hydrogen production in conjunction with organic acids and carbohydrates analyses, it was hypothesized that the high FVW-to-biohydrogen conversion rate achieved was powered by lactate metabolism., European Commission-H2020-MSCA-IF-2019 project UP-GRAD (894515), Junta de Castilla y Leon - FEDER (program CLU 2017-09, CL-EI-2021-07 & UIC 315)

Poultry livestock profitability significantly depends on feed, accounting for 60–70% of the total production cost, of which protein sources are among of the most expensive ingredients. The maintenance of profitability while meeting feed demand and reducing the environmental impact represents a considerable challenge driving research of alternative protein sources (APS), such as insects and algae meals. This study employs, for the first time, techno-economic assessment (TEA) methodology to evaluate the technological performance and the industrial feasibility of an APS-based poultry feed production method based on the valorization of the pre-treated organic fraction of municipal solid waste (OFMSW) as a substrate for Hermetia illucens larval growth and microalgae cultivation. The Excel-based analysis, which evaluated the mass and energy balance as well as the income statement, was integrated with a thematic analysis focused on exploring how the overall value attributed to the sustainability concept is reflected in the willingness to adopt sustainable business models by entrepreneurs in the poultry sector. Despite the ability to generate revenues, the model cannot be said to be profitable for animal feed production due to the strong dependence of its profitability on scale economy logics. Enabling solutions could be derived from the recovery of abandoned infrastructures, government financial incentives, and integrated systems associating OFMSW treatment with poultry farming, thus resulting in marked economic sustainability and profitability: key elements from the poultry entrepreneurs’ point of view.

Orange peels (OPs) were valorized in a lab-scale biorefinery loop for the recovery of limonene and the subsequent production of volatile fatty acids (VFAs) and activated carbon (AC). Solid/liquid extraction of limonene was optimized using n-hexane at 85 °C with an OPs-to-solvent ratio of 2:1, allowing for a limonene recovery yield of 1.20% w/w. Then, post-extraction OPs were used for the production of both VFAs and AC. For VFA production, a hydraulic retention time (HRT) of 5 days and a total solid (TS) inlet content of 10% w/w were adopted leading to a VFA yield of about 43% gVFAs/gTS. Adsorption tests revealed that, among all the solid matrixes tested, only powdered activated carbon (PAC) was able to discriminate no-VFA compounds and allowed for VFA purification. For AC production, post-extraction OPs were firstly converted into biochar through slow pyrolysis at 550 °C for 1 h and then physically activated with CO2 at 880 °C for 1 h. Extraction did not appreciably affect OP properties, while pyrolysis increased the carbon content (from 43 to 83%) and the heating value (from 17 to 29 MJ/kg) of the material. Physical activation of OP biochar increased its surface area by almost ten times, from 40 to 326 m2/g, proving the effectiveness of the treatment.

Background Wood represents the majority of the biomass on land and constitutes a renewable source of biofuels and other bioproducts. However, wood is recalcitrant to bioconversion, raising a need for feedstock improvement in production of, for instance, biofuels. We investigated the properties of wood that affect bioconversion, as well as the underlying genetics, to help identify superior tree feedstocks for biorefining. Results We recorded 65 wood-related and growth traits in a population of 113 natural aspen genotypes from Sweden (https://doi.org/10.5061/dryad.gtht76hrd). These traits included three growth and field performance traits, 20 traits for wood chemical composition, 17 traits for wood anatomy and structure, and 25 wood saccharification traits as indicators of bioconversion potential. Glucose release after saccharification with acidic pretreatment correlated positively with tree stem height and diameter and the carbohydrate content of the wood, and negatively with the content of lignin and the hemicellulose sugar units. Most of these traits displayed extensive natural variation within the aspen population and high broad-sense heritability, supporting their potential in genetic improvement of feedstocks towards improved bioconversion. Finally, a genome-wide association study (GWAS) revealed 13 genetic loci for saccharification yield (on a whole-tree-biomass basis), with six of them intersecting with associations for either height or stem diameter of the trees. Conclusions The simple growth traits of stem height and diameter were identified as good predictors of wood saccharification yield in aspen trees. GWAS elucidated the underlying genetics, revealing putative genetic markers for bioconversion of bioenergy tree feedstocks.

Although the whole microalgal biomass is typically used as a feedstock for hydrothermal liquefaction (HTL), the conversion of a primary metabolite (i.e., carbohydrate) to biocrude is very low. In this study, a self-settling cyanobacterium (i.e., Chroococcidiopsis sp.) was used to understand the effect of carbohydrate removal, as a pretreatment, on the net energy recovery from the residual biomass. The optimum biocrude yields from pretreated and control biomass were 50.2% (350 °C) and 41.3% (300 °C), respectively. For the temperature range studied, the biocrude yield from the pretreated biomass was higher compared to that obtained from the control feedstock. Further, maximum alkane formation of 42.7 and 23.3% occurred for pretreated and control biomass, respectively, at 325 °C. Total organic carbon and total nitrogen values in the aqueous phase liquid obtained from pretreated biomass were at least 1.31 and 1.23 times lower when compared to the corresponding values obtained from control biomass. When APL was recycled as a source of nutrients, it reduced the biomass yield (24.1%) and pigment content (68.4%) in Chroococcidiopsis sp. Further, a model was developed to understand how the cellular carbohydrate content would affect the net energy recovery for the proposed biorefinery route. The authors would like to acknowledge the support of the Qatar National Research Fund (QNRF, a member of Qatar Foundation) for providing the funding (under grant NPRP8-646-2-272 ) for this study. Scopus

As the global population rises, agriculture and industry are under increasing pressure to become more sustainable in meeting this growing demand, while minimizing impacts on global emissions, land use change, and biodiversity. The development of efficient and symbiotic local bioeconomies can help to respond to this challenge by using land, resources, and side streams in efficient ways tailored to the needs of different regions. Green biorefineries offer a unique opportunity for regions with abundant grasslands to use this primary resource more sustainably, providing feed for cows, while also generating feed for monogastric animals, along with the co-production of biomaterials and energy. The current study investigates the impact of a green biorefinery co-product, leaf protein concentrate (LPC), for input to a pig farm, assessing its impact on pig diets, and the extended impact on the bioenergy performance of the pig farm. The study found that LPC replaced soya bean meal at a 50% displacement rate, with pigs showing positive performance in intake and weight gain. Based on laboratory analysis, the resulting pig slurry demonstrated a higher biogas content and 26% higher biomethane potential compared with the control slurry. The findings demonstrate some of the local synergies between agricultural sectors that can be achieved through extended green biorefinery development, and the benefits for local bioeconomy actors.

The bioeconomy is positioned as a sustainable pathway to address the climate crisis and decrease the consumption of fossil resources. Life cycle methodologies are recognised as useful tools for assessing sustainability issues of production and consumption patterns. Nevertheless, the Social Life Cycle Assessment (S-LCA) methodology is less explored despite its potential, although it is true that social sustainability assessment in promoting bioeconomy strategies requires more attention. This study describes the state of the art of the S-LCA methodology under the bioeconomy framework, critically analysing the main procedural and practical issues of its implementation, and the eventual specificities, as well as providing some of the challenges for future studies. This review highlights methodological weaknesses that require further research, related to the definition of system boundaries and cut-off criteria, the method of impact assessment, and the selection of societal issues and stakeholders, as well as uncertainty, among others. In addition, particularities of the bioeconomy in the life perspective were noted, such as multifunctionality and allocation issues of bio-based products, as well as the strong interest in biofuel production systems. Therefore, more efforts are desirable to address the diversity of challenges towards the progress of the S-LCA method in line with other life cycle approaches (environmental and economic). However, the updated S-LCA Guidelines represent a useful and valuable starting point on the way towards a comprehensive (i.e., diverse social concerns) and standardised social assessment under a life cycle perspective This research has been supported by the project Enhancing diversity in Mediterranean cereal farming systems (CerealMed) project funded by PRIMA Programme and FEDER/Ministry of Science and Innovation–Spanish National Research Agency (PCI2020-111978). R.R.L., S.G.G. and M.T.M. belong to the Galician Competitive Research Groups (GRC)_ED431C-2021/37, co-funded by Xunta de Galicia and FEDER (EU) SI

Adding high-value products, such as carbon-based electrode materials for electrochemical energy storage, to the value chain of biorefinery may increase the profits of the whole concept. In this work, carbon-based supercapacitor electrode materials were produced by chemical activation (using KOH) of two fractions of bio-oil (aerosol and condensed) as well as bio-char precursors, all of them originally made from fast pyrolysis of stem wood from pine and spruce. The produced materials show a hierarchical porous structure, a high surface area (1300–1500 m2 g−1) and, almost double the specific capacitance (149–152 F g−1 @ 50 mA g−1) compared to commercially available activated carbon (79 F g−1 @ 50 mA g−1). The benefit of using bio-oils compared to biochar is having an electrode material almost free from metal impurities alongside marginally higher energy storage performance. Together with the material yield in the production chain (fast pyrolysis and activation), a normalized energy storage value was presented for each material that may be used in the future to select the best techno-economic route for the whole concept.

Nowadays, cassava leaves are mostly treated as a byproduct of cassava root production, yet this readily available biomass is rich in protein with a balanced content of amino acids. Cassava leaves therefore represent a promising, underutilized biomass for extraction of proteins. The purpose of this study was to provide updated information on the feasibility of producing cassava leaf protein concentrate for use in feed and food. In this context, protein concentrates were refined from cassava leaves using different precipitation methods and the refining process evaluated with focus on protein, amino acids and selected antinutritional factors. Crude protein was mainly distributed to the press cake and protein concentrates during the two processing steps, i.e., pressing and precipitation, and between 21% and 26% (w/w) of leaf crude protein was recovered in the concentrates. After drying, these contained 40–45% crude protein with an amino acid profile comparable to soybean and tolerable levels of tannins (>1% of TS) for feed purposes. However, the refining process did not significantly reduce the cyanogenic potential, i.e., the total amount of releasable HCN, which accumulated in the dried protein product to around 150–250 ppm. This lies significantly above the 10–50 ppm deemed safe for food and feedstuff by several food safety authorities. Based on these results, extraction of leaf protein from cassava appears promising, but additional research is required to evaluate its full potential, especially in relation to its use in food products.

Lignosulfonates are industrial biorefinery products that are characterized by significant variability and heterogeneity in their structural composition. Typically, they exhibit high dispersities in...

Abstract In a Green Biorefinery, grass silage can be a source for lactic acid, proteins, amino acids and fibres. Processing residues can be used for anaerobic digestion and methane production. But by changing the ensiling conditions, butyric acid fermentation can be achieved. That makes grass silage also a potential substrate for a combined butyric acid and methane production. The objective of this study was to determine the potential of butyric acid production at different ensiling conditions applied to grass and measuring the methane yield potential of solid residues after a separation step. The highest butyric acid concentration in the produced press juice was 20.1 ± 4.5 g kg−1 and was achieved by carbonated lime addition and a reduced dry matter content after 90 days at mesophilic storage conditions. This resulted in a theoretical butyric acid yield of 332 kg ha−1 a−1. For the fibrous leftover press cake, a theoretical methane production potential of 2778 m3CH4 ha−1 a−1 was reached. The results show that theoretically a combined production of butyric acid and methane can be realised in a Green Biorefinery concept. Graphic Abstract

During acidic pretreatment of renewable lignocellulosic biomass, lignin depolymerization/repolymerization reactions often occur, which intensifies lignin inhibition on cellulose hydrolysis generally through lignin-derived inhibitors formation, unproductive binding and physical blockage effect. In order to improve the enzymatic digestibility of dilute acid pretreated hardwood, in this work various additives were compared and their inhibition mitigating effects were examined. It was revealed that 2-naphthol addition reduced the formation of inhibitory derivatives from lignin, thus increasing the enzymatic hydrolysis yield of the whole slurry after dilute acid pretreatment. The addition of phenolic acids largely diminished enzyme binding effect of the insoluble lignin. Moreover, the 2-naphthol-7-sulfonate additive led to the most pronounced mitigation on physical blockage effect of lignin, as XPS and SEM results showed the significant removal of surface lignin. This work revealed the different mechanisms of various additives in mitigating lignin inhibition, and provided a better understanding on utilizing proper additives to improve biomass saccharification for biorefinery applications.

Nanocellulose (NC) is a unique and promising natural material derived from native cellulose. It has attracted much attention for its versatility in construction composites, which have improved chemical and mechanical properties. This review covers the type of biomass used and NC production methods, emphasizing biotechnological routes, which promote their biological properties (biocompatibility, biodegradability and low toxicity), fundamental for medical applications. NC has many hydroxyl groups on its surface, enabling its structure to be modifiable, adaptable and viable for various fields. Furthermore, NC-based biosensors are suitable for food quality control, monitoring environmental analytes, and particularly in health diagnostics, such as COVID19 detection. The developed analytical devices were described in a table, including information about the sensor molecule, reading system, analyte, range, detection limit, sensitivity and analytical performance. © 2021 Wiley-VCH GmbH

The production of chemicals from biomass has received significant attention due to its potential to reduce greenhouse gas (GHG) emissions. In this work, we develop a systematic framework to quantit...

Life cycle assessments of fuel bioethanol produced in Uruguay from liquid hot water pretreated switchgrass were performed for two scenarios: the production of ethanol and electricity and a biorefinery producing ethanol, electricity, furfural, acetic, and formic acid. Experimental data and material and energy balances derived from the simulations were used to analyze the global warming potential of fuel bioethanol. Greenhouse gas (GHG) emissions in both scenarios were lower than the reference emissions for fossil fuel. The biorefinery scenario had a better performance in terms of environmental impacts, and the biofuel produced met GHG reduction requirements. Switchgrass composition, enzyme dosage, fermentation and hydrolysis efficiency, and solids content had a significant effect on environmental performance, with enzyme use being the most significant factor. A multi-objective optimization was used to find the values of solid content and enzyme dose that minimize GHG emissions and the minimum ethanol selling price (MESP). An enzyme dosage of 37 mgprotein/gglucan and solids content of 21% w/w were the optimal conditions for bioethanol production with an associated GHG value of 2 ± 5 g CO2 eq./MJethanol and a MESP of $0.84/L.

Levoglucosan is a promising sugar present in the lignocellulose pyrolysis bio-oil, which is a renewable and environment-friendly source for various value-added productions. Although many microbial catalysts have been engineered to produce biofuels and chemicals from levoglucosan, the demerits that these biocatalysts can only utilize pure levoglucosan while inhibited by the inhibitors co-existing with levoglucosan in the bio-oil have greatly limited the industrial-scale application of these biocatalysts in lignocellulose biorefinery. In this study, the previously engineered Escherichia coli LGE2 was evolved for enhanced inhibitor tolerance using long-term adaptive evolution under the stress of multiple inhibitors and finally, a stable mutant E. coli-H was obtained after ~ 374 generations’ evolution. In the bio-oil media with an extremely acidic pH of 3.1, E. coli-H with high inhibitor tolerance exhibited remarkable levoglucosan consumption and ethanol production abilities comparable to the control, while the growth of the non-evolved strain was completely blocked even when the pH was adjusted to 7.0. Finally, 8.4 g/L ethanol was achieved by E. coli-H in the undetoxified bio-oil media with ~ 2.0% (w/v) levoglucosan, reaching 82% of the theoretical yield. Whole-genome re-sequencing to monitor the acquisition of mutations identified 4 new mutations within the globally regulatory genes rssB, yqhA, and basR, and the − 10 box of the putative promoter of yqhD-dgkA operon. Especially, yqhA was the first time to be revealed as a gene responsible for inhibitor tolerance. The mutations were all responsible for improved fitness, while basR mutation greatly contributed to the fitness improvement of E. coli-H. This study, for the first time, generated an inhibitor-tolerant levoglucosan-utilizing strain that could produce cost-effective bioethanol from the toxic bio-oil without detoxification process, and provided important experimental evidence and valuable genetic/proteinic information for the development of other robust microbial platforms involved in lignocellulose biorefining processes.

There is an environmental concern regarding the use of petroleum-based lubricants, which are generally toxic and nonbiodegradable. Biobased lubricants, such as vegetable oils, are the alternative: they show excellent lubricity, are readily biodegradable and nontoxic. However, a major disadvantage of using vegetable oils in lubricant applications is their lack of thermo-oxidative stability, which can be improved by antioxidant additives. Here, we propose the use of lignin-based additives in biolubricant formulations to improve this feature, based on lignin’s known antioxidant properties. To ensure a stable dispersion in vegetable oil, lignin was partially esterified. Antioxidant properties of lignin before and after palmitoylation were demonstrated in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Four different lignin-based fractions, commercial Protobind P1000 soda lignin from straw, solvolytically fractionated Protobind P1000 lignin and two lignin fractions from reductively catalyzed fractionation (RCF) of native birch wood, were tested in biolubricant formulations with castor oil as base oil. Those lignin fractions exhibited excellent performance compared to butylated hydroxytoluene (BHT), a commonly used petroleum-based antioxidant. Formulations of modified lignin in castor oil possess improved thermo-oxidative stability, as illustrated by their increased oxidation induction time. Additionally, rheological and tribological tests demonstrate similar, or in some cases improved, lubricating properties compared to castor oil. This study showcases the successful incorporation of lignin-based antioxidants in biolubricant formulations, tackling the major disadvantage of vegetable oils as environment-friendly lubricants.

In this work, the anaerobic digestion of three microalgae (Chlorella sp., Nannochloropsis sp., and Scenedesmus sp.) and their residues, resulting from the oil extraction process and the in situ transesterification reaction for biodiesel production, using two inoculums (sewage sludge and poultry manure) for biogas production was investigated. It was found that the biogas production from digestion of oil-extracted microalgae residue with sewage sludge reached values ​​similar to those obtained with raw microalgae (around 500 NL kg−1 VS). Both the volume of biogas generated from the microalgae residue from the extraction process of its oil and the quality of the biogas produced reflect the value of this residue to be valorized by anaerobic digestion. This approach based on a biorefinery concept and focusing on the anaerobic digestion process could be a key technology for energy production from biomass.