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Biochar, a carbon‐rich material derived from organic biomass under low‐O2 conditions, has gained importance due to its role in mitigating climate change by sequestering carbon. It can be used as an alternative energy source and has applications in nutrient cycling, improving soil properties, and removing heavy metals and organic pollutants, thus contributing to sustainable agriculture and environmental remediation. In the face of alarming climate change, rising energy demand, and increasing pollution, the integration of biochar production into biorefineries is an important strategy to promote a sustainable and circular economy. Adopting a holistic approach to biomass utilization by developing strategies to maximize biochar production along with the production of other value‐added products while improving its quality can increase biorefineries' overall sustainability and efficiency. Fine‐tuning the biorefinery process from feedstock selection to co‐production, optimizing pyrolysis conditions, and integrating it with other technologies can help to achieve this goal while generating zero waste and diversified revenues. With the biochar market growing exponentially, further research into the long‐term impact of biochar on carbon sequestration and its application in the environment is the next step. [ABSTRACT FROM AUTHOR]

This work presents a comprehensive Social Life Cycle Assessment (S-LCA) and Social Cost-Benefit Analysis (S-CBA) conducted as part of a research project, studying biofuel production for the maritime and aviation sectors, from various types of non-food waste biomasses. The inclusion of social considerations complements and expands on the environmental and economic ones. The importance of social group criteria was determined through expert questionnaires, leading to the identification of social impacts groups and social criteria from stakeholders across participating countries. The results successfully identified and quantified social impacts, and align with those reported in similar cases in relevant literature. Social Cost-Benefits, monetarizing social factors, demonstrated several social benefits, including reduction in Greenhouse Gas Emissions. However, it also highlighted social costs, such as Economic Costs associated with the initial investment. The study revealed critical social hotspots within the impact categories, making significant strides in understanding the social impacts of biofuel production, providing valuable insights for decision-makers, and contributing to the broader goal of sustainable and socially responsible biofuel production. [ABSTRACT FROM AUTHOR]

The global spread of invasive plants is an important environmental problem and a real threat to biological diversity, with significant impacts on agriculture, forestry, and human and animal health. Invasive plant eradication produces large amounts of plant biomass, which should be safely utilized. The study reviews possibilities for using biomass of invasive plant species in the bioeconomy to safely convert them to items of value. Invasive plant biomass can be used as fuel or for energy production applying either biochemical or thermochemical processing technologies. The biomass of invasive plants also can be used for energy production or isolation of biologically active components. Invasive plants contain many groups of substances providing their defense potential against predators; these substances participate in metabolic regulation processes and others. Amongst the substances of interest for bioeconomy are lipids, polyphenols, alkaloids, carbohydrates, plant fibers, and essential oils. In the development of invasive plant biomass utilization strategies, the bio-based value pyramid and the waste hierarchy should be considered. Scientific sound strategies of invasive plant management will limit their spread and provide economic benefits via their eradication. [ABSTRACT FROM AUTHOR]

Despite advances in biofuel production and biomass processing technologies, biorefineries still experience commercialization issues. When costs exceed revenues, their long-term economic sustainability is threatened. Although integrated biorefineries have significant global potential due to process integration and product co-generation, it is crucial that they generate a positive net return, thereby incentivizing their continual operation. Nonetheless, research and development into new system designs and process integration are required to address current biorefinery inefficiencies. The integration of Bitcoin mining into biorefineries represents an innovative approach to diversify revenue streams and potentially offset costs, ensuring the economic viability and commercial success of biorefineries. When using bio-H2, a total of 3904 sats/kg fuel can be obtained as opposed to 537 sats/kg fuel when using syngas. Bitcoin, whether produced onsite or not, is an accretive asset that can offset the sales price of other produced biochemicals and biomaterials, thereby making biorefineries more competitive at offering their products. Collaborations with policy makers and industry stakeholders will be essential to address regulatory challenges and develop supportive frameworks for widespread implementation. Over time, the integration of Bitcoin mining in biorefineries could transform the financial dynamics of the bio-based products market, making them more affordable and accessible whilst pushing towards sustainable development and energy transition. [ABSTRACT FROM AUTHOR]

The global spread of invasive plants is an important environmental problem and a real threat to biological diversity, with significant impacts on agriculture, forestry, and human and animal health. Invasive plant eradication produces large amounts of plant biomass, which should be safely utilized. The study reviews possibilities for using biomass of invasive plant species in the bioeconomy to safely convert them to items of value. Invasive plant biomass can be used as fuel or for energy production applying either biochemical or thermochemical processing technologies. The biomass of invasive plants also can be used for energy production or isolation of biologically active components. Invasive plants contain many groups of substances providing their defense potential against predators; these substances participate in metabolic regulation processes and others. Amongst the substances of interest for bioeconomy are lipids, polyphenols, alkaloids, carbohydrates, plant fibers, and essential oils. In the development of invasive plant biomass utilization strategies, the bio-based value pyramid and the waste hierarchy should be considered. Scientific sound strategies of invasive plant management will limit their spread and provide economic benefits via their eradication.

Featured Application: Potential application of the outcomes of the present study is feasible, for wastewater bioremediation with concurrent cost-efficient biofuel production, along with value-added health product and biofuel development, while also reducing the carbon footprint, certainly after implementation of the necessary regulation sandboxes, to promote environmental and human health protection and also job creation and economy strengthening. In the current study, the cultivation of microalgae on wastewater-based substrates is investigated for an effective natural wastewater treatment that also generates biofuels and value-added products beneficial to human health. Additionally, the health of ecosystems can be evaluated via microalgae. The utilization of microalgae as bioindicators, biofuel producers, and wastewater treatment providers, under the biorefinery concept, is covered in this article. In fact, bioremediation is feasible, and microalgae culture can be used to efficiently process a variety of effluents. Along with wastewater processing and the creation of value-added substances, bioconversion concurrently offers a viable and promising alternative for reducing CO2 greenhouse gas emissions to contribute to climate change mitigation. The microalgal biorefinery being considered as the third generation is unique in that it addresses all the aforementioned problems, in contrast to lignocellulosic biomass from agricultural waste in second-generation biorefineries and edible crops in first-generation biorefineries. In particular, one of the most promising natural resources for the manufacture of biofuel, including biodiesel, bioethanol, biomethane, and biohydrogen, is found to be microalgae. Furthermore, products of high value, like fatty acid methyl esters, astaxanthin, β-carotene, DHA, and EPA can be made. Hence, microalgal biomass offers a substitute for the development of biofertilizers, bioplastics, pharmaceuticals, cosmetics, animal and aquatic feeds, and human nutrition products, thus promoting human and environmental health. [ABSTRACT FROM AUTHOR]

Lignocellulose revalorization has emerged as a major solution to mitigate the increasing energy demand of the growing population. Lignocellulosic biomass is considered the building block of plant cell walls and is mainly composed of cellulose, hemicellulose, and lignin. The biomass needs to be processed efficiently to produce value-added products and bioenergy. Therefore, this study aims to systematically review various conversion technologies, like thermal conversion, and biological pretreatments available to achieve this. The use of the biological pretreatment method is cost-effective and eco-friendly. Many microorganisms, different strains of bacteria, fungus, etc., are used here to exploit their cellulolytic and ligninolytic properties. It covers the life cycle assessment of lignocellulose pretreatment, downstream processing for conversion of lignocellulose to biofuel, and techno-economic analysis. The attention has also been given to the development of biorefineries to enhance the production efficiency of bioenergy from the lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

This work presents a comprehensive Social Life Cycle Assessment (S-LCA) and Social Cost-Benefit Analysis (S-CBA) conducted as part of a research project, studying biofuel production for the maritime and aviation sectors, from various types of non-food waste biomasses. The inclusion of social considerations complements and expands on the environmental and economic ones. The importance of social group criteria was determined through expert questionnaires, leading to the identification of social impacts groups and social criteria from stakeholders across participating countries. The results successfully identified and quantified social impacts, and align with those reported in similar cases in relevant literature. Social Cost-Benefits, monetarizing social factors, demonstrated several social benefits, including reduction in Greenhouse Gas Emissions. However, it also highlighted social costs, such as Economic Costs associated with the initial investment. The study revealed critical social hotspots within the impact categories, making significant strides in understanding the social impacts of biofuel production, providing valuable insights for decision-makers, and contributing to the broader goal of sustainable and socially responsible biofuel production.

Environmental pollution is a big challenge that has been faced by humans in contemporary life. In this context, fossil fuel, cement production, and plastic waste pose a direct threat to the environment and biodiversity. One of the prominent solutions is the use of renewable sources, and different organisms to valorize wastes into green energy and bioplastics such as polylactic acid. Chlorella vulgaris, a microalgae, is a promising candidate to resolve these issues due to its ease of cultivation, fast growth, carbon dioxide uptake, and oxygen production during its growth on wastewater along with biofuels, and other productions. Thus, in this article, we focused on the potential of Chlorella vulgaris to be used in wastewater treatment, biohydrogen, biocement, biopolymer, food additives, and preservation, biodiesel which is seen to be the most promising for industrial scale, and related biorefineries with the most recent applications with a brief review of Chlorella and polylactic acid market size to realize the technical/nontechnical reasons behind the cost and obstacles that hinder the industrial production for the mentioned applications. We believe that our findings are important for those who are interested in scientific/financial research about microalgae. [ABSTRACT FROM AUTHOR]

Abstract Sustainably produced renewable biomass has the potential to replace fossil-based feedstocks, for generation of biobased fuels and chemicals of industrial interest, in biorefineries. In this context, seaweeds contain a large fraction of carbohydrates that are a promising source for enzymatic and/or microbial biorefinery conversions. The thermoanaerobe Thermoanaerobacterium AK17 is a versatile fermentative bacterium producing ethanol, acetate and lactate from various sugars. In this study, strain AK17 was engineered for more efficient production of ethanol by knocking out the lactate and acetate side-product pathways. This was successfully achieved, but the strain reverted to acetate production by recruiting enzymes from the butyrate pathway. Subsequently this pathway was knocked out and the resultant strain AK17_M6 could produce ethanol close to the maximum theoretical yield (90%), leading to a 1.5-fold increase in production compared to the wild-type strain. Strain AK17 was also shown to successfully ferment brown seaweed hydrolysate from Laminaria digitata to ethanol in a comparatively high yield of 0.45 g/g substrate, with the primary carbon sources for the fermentations being mannitol, laminarin-derived glucose and short laminari-oligosaccharides. As strain AK17 was successfully engineered and has a wide carbohydrate utilization range that includes mannitol from brown seaweed, as well as hexoses and pentoses found in both seaweeds and lignocellulose, the new strain AK17_M6 obtained in this study is an interesting candidate for production of ethanol from both second and third generations biomass.

Growing interest in sustainable sources of chemicals and energy from renewable and reliable sources has stimulated the design and synthesis of renewable Schiff-base (iminium) ionic liquids (ILs) to replace fossil-derived ILs. In this study, we report on the synthesis of three unique iminium-acetate ILs from lignin-derived aldehyde for a sustainable “future” lignocellulosic biorefinery. The synthesized ILs contained only imines or imines along with amines in their structure; the ILs with only imines group exhibited better pretreatment efficacy, achieving >89% sugar release. Various analytical and computational tools were employed to understand the pretreatment efficacy of these ILs. This is the first study to demonstrate the ease of synthesis of these renewable ILs, and therefore, opens the door for a new class of “Schiff-base ILs” for further investigation that could also be designed to be task specific.

Sustainably produced renewable biomass has the potential to replace fossil-based feedstocks, for generation of biobased fuels and chemicals of industrial interest, in biorefineries. In this context, seaweeds contain a large fraction of carbohydrates that are a promising source for enzymatic and/or microbial biorefinery conversions. The thermoanaerobe Thermoanaerobacterium AK17 is a versatile fermentative bacterium producing ethanol, acetate and lactate from various sugars. In this study, strain AK17 was engineered for more efficient production of ethanol by knocking out the lactate and acetate side-product pathways. This was successfully achieved, but the strain reverted to acetate production by recruiting enzymes from the butyrate pathway. Subsequently this pathway was knocked out and the resultant strain AK17_M6 could produce ethanol close to the maximum theoretical yield (90%), leading to a 1.5-fold increase in production compared to the wild-type strain. Strain AK17 was also shown to successfully ferment brown seaweed hydrolysate from Laminaria digitata to ethanol in a comparatively high yield of 0.45 g/g substrate, with the primary carbon sources for the fermentations being mannitol, laminarin-derived glucose and short laminari-oligosaccharides. As strain AK17 was successfully engineered and has a wide carbohydrate utilization range that includes mannitol from brown seaweed, as well as hexoses and pentoses found in both seaweeds and lignocellulose, the new strain AK17_M6 obtained in this study is an interesting candidate for production of ethanol from both second and third generations biomass. [ABSTRACT FROM AUTHOR]

The European Union has recommended that about 10–50% of the global energy requirement should be supplemented by waste biomass resources by 2050 in order to achieve the objective of having net-zero-emission economies. This has led to intensive research being conducted on developing appropriate biofuel production technologies using advanced or integrated systems to tackle local, national, and global energy challenges using waste feedstock. Researchers have realized the potential of microbes (e.g., yeast strains) for bioenergy production. For this paper, both non-oleaginous and oleaginous yeasts were reviewed, with a specific focus being placed on their diversity in metabolism and tolerance to the various challenges that arise from the use of waste feedstock and influence bioprocessing. Gathering in-depth knowledge and information on yeast metabolism has paved the way for newer and better technologies to employ them for consolidated biorefineries to not only produce biofuels but also to cut down process expenses and decrease the risks of net carbon emissions. The rationale for using yeast strains improved by metabolic engineering and genetic manipulation that can substantially meet the challenges of alternate fuel resources is also described in this paper. This literature review presents the advantages and disadvantages of yeast-based biofuel production and highlights the advancements in technologies and how they contrast to conventional methods. Over the last decade, scientific publications have endorsed the idea of biorefineries for environmentally friendly, cost-effective, and sustainable biofuel production. [ABSTRACT FROM AUTHOR]

Bio-based materials have been used traditionally for millennia. Their use was overtaken in recent times by the discovery and utilization of fossil-based resources for materials and energy. However, concerns about the non-renewability of fossil resources and greenhouse gas and other emissions associated with their use have brought forth a renewed interest in using bio-based materials in recent years. The environmental advantages of bio-based materials cannot be taken for granted without a rigorous scientific assessment. Many tools based on energy, economics, and environmental impacts have been used. Life cycle assessment is one such tool developed and successfully utilized for the environmental assessment of biofuels and bioproducts. However, many methodological challenges, among other things related to system boundaries, functional units, allocation, and carbon accounting, still need further research and consideration. In this work, the related issues are summarized, and the directions for addressing them are discussed. Despite the methodological challenges in their assessment, biofuels and bioproducts show promise in terms of their environmental advantages compared to their fossil-oriented counterparts. These advantages can be further enhanced by utilizing all parts of the feedstock biomass, especially for value-added materials and chemicals via biorefineries.

The depolymerization of lignin to produce renewable value-added building block chemicals has received increased attention from both industry and academia, as its facilitation is a key in the development of future biorefinery technologies. The main challenge in lignin depolymerization relies on its complex structure. Numerous efforts have shown that catalysts, solvents, reaction parameters, and physiochemical properties of lignin significantly affect the depolymerization reaction of lignin. Solvents are crucial components of the reaction system and affect the performance of the lignin depolymerization process. A good solvent can promote the solubility of lignin and enhance the catalyst–lignin interactions, and could also stabilize the reactive intermediates. However, the relationship and dependence of the molecular structure of lignins with its solubility and reactivity in different solvents are poorly understood. Thus, it is important to understand the influence of solvents on the reaction mechanism, the thermodynamic state of lignin, intermediates, products, and catalysts' stability. In this article, various solvents used in the depolymerization of different types of lignin reactions are extensively overviewed. Special attention is paid to comparing the conversion of lignin, yield of bio-oil, and yield of monomers in the presence of different polarity-categorized solvents and binary solvents. [ABSTRACT FROM AUTHOR]

The biosorption potential of biowaste leftover from the fixed oil biorefinery process of Nigella sativa L. for the production of biofuel was first explored on the basis of concepts of bioeconomy and zero-waste to clean the impurity of synthetic dye from water environment in the current study. A triarylmethane-type synthetic dye called FD&C Green No 3 (E143, C.I. 42,053) as model compound was used to investigate the biosorption performance of biorefinery waste–based novel biosorbent. The main process parameters (biowaste amount (m), pH, FD&C Green No 3 concentration (Ci), and biosorption time (t)) optimization, kinetics, equilibrium, and thermodynamics batch-type experiments were done to clarify the nature of synthetic dye biosorption operation. The characterization and comparison studies were also made for the green waste as a biosorbent material. The optimum values of biosorption process variables studied were found to be Ci of 15 mg L−1, t of 360 min, m of 10 mg, and pH of 3. Referring to the results of statistical tests of coefficient of determination (R2), adjusted coefficient of determination (AdjR2), and root mean squared error (RMSE), it was seen that the experimental data of biosorption followed Elovich kinetics model (R2: 0.96, AdjR2: 0.96, and RMSE: 6.76 for 15 mg L−1) and Freundlich isotherm model (R2: 1.00, AdjR2: 1.00, and RMSE: 1.20). The thermodynamics data obtained showed that the process was physical, spontaneous, and energetically favorable. Fourier transform infrared spectroscopy and scanning electron microscopy studies indicated that the biorefinery waste possessed an inhomogeneous surface morphology including many cavities and protuberances, and a rich functional group profile. Considering Langmuir biosorption capacity of biowaste (119.86 mg g−1), it exhibited higher purification performance than various sorbent materials reported in the literature. This pre-feasibility study indicated that the biorefinery waste of N. sativa L. could be utilized as promising biosorbent material to purify the synthetic dye impurity from aqueous environment, and the integration of biosorption with the processes of biorefinery and biofuel production could make all these operations more economically and environmentally sustainable. [ABSTRACT FROM AUTHOR]

Edible-fungal-based solid-state fermentation holds promise for sustainable food and biofuel production. Understanding the role of microbial communities in fungal substrates is crucial. Birch-based substrates were treated with autoclaving (121 °C, at 2 bar) or hot air pasteurization (75–100 °C), followed by incubation with and without shiitake (Lentinula edodes) inoculum. Mycelial growth was monitored by CO2 release and microbial biomass by phosphate-lipid fatty acid (PLFA). DNA sequencing was used to analyze the microbial communities. Results showed successful colonization of shiitake on all substrates, regardless of pasteurization temperatures and coexisting microbes. Total microbial respiration (CO2) and PLFA biomass showed no significant differences between pasteurization regimes. However, significant microbial differences were found between shiitake-inoculated and non-inoculated treatments. DNA sequencing revealed the dominance of Phyllobacterium, Sphingomonas, and Pelomonas genera in all inoculated substrates, while non-inoculated substrates were abundant in Bacillus spp. and Paenibacillus spp. of the Firmicutes phylum. This study provides preliminary insights into the microbial community in birch-based shiitake substrates, facilitating further investigation of bacteria involved in shiitake mycelium growth promotion and biochemical conversion for biofuel production. [ABSTRACT FROM AUTHOR]

Saccharification recalcitrance significantly limits the conversion of lignocellulosic biomass to valuable end products. The intricate arrangement between cell wall matrix polysaccharides, proteins, and lignin makes the cell wall structure a challenging substrate for carbohydrase and ligninase accessibility. Cellulose valorization from biomass or via conversion into valuable bioproducts, including bioethanol, is a strategic pathway for the economic viability and full implementation of lignocellulose biorefineries. The enzymatic hydrolysis of cellulose into sugar monomers has emerged as the most efficient biomass conversion technology. Synergistic degradation of cellulosic biomass components is achieved using a consortium of enzymes, including cellulases, lytic polysaccharide monooxygenases, and cellobiose dehydrogenases combined with proteins, such as swollenins and expansins. The immobilization of cellulose-degrading enzymes with an appropriate matrix requires careful examination to achieve successful cellulose breakdown. Genetic modification of filamentous fungi provides an avenue to generate strains with high enzyme production. This review focuses on the mechanisms of action of cellulose-degrading enzymes and their contribution to improving bioethanol production from plant biomass and discusses technologies and strategies aimed at reducing costs for lignocellulosic biorefineries. Highlights: Valorization of cellulose is challenging due to it is complex structure Cellulose degradation requires synergistic interactions of several enzyme types Reducing biorefinery costs requires enzyme immobilization and genetic engineering Cellulase immobilization enhances operational stability and allows enzyme recovery [ABSTRACT FROM AUTHOR]

Soybean straw is an agricultural residue of soybean whose yield is up to 1.5 kg per kg of soybean. The existing literature shows the vast potential of soybean straw as an environmentally friendly carbon source to produce value-added chemicals, materials, fuels, and energy in a similar way to oil refineries. However, the use of this biomass on a commercial scale in biorefineries still faces some challenges. This comprehensive review discusses the available literature in several topics related to the application of this agricultural residue, such as productive potential; quality of feedstock; feedstock delivery; challenges in the breakdown of the cell wall polymeric structure; conversion process into chemicals, heat, and power; and the production of advanced materials. Several examples of fiber treatment are presented to demonstrate the potential of taking advantage of the mechanical properties of soybean straw. Current knowledge gaps and challenges related to the conversion of soybean straw to fermentable sugars and the low performance of hydrolysate fermentation are discussed, besides other applications in the sugar platform. Thermochemical conversion is discussed as well because of the possibility of readily employing this biomass in co-processing plants. In the end, an outlook of potential directions for future research towards the next generation of integrated soybean/soybean straw biorefinery is presented to demonstrate the potential of further developing applications for this biomass. Synopsis Potential applications of soybean straw are reviewed, with a focus on the sustainable production of biofuels, bioenergy, and advanced materials. [ABSTRACT FROM AUTHOR]

To evaluate jojoba oil (Jo) in high-added-value products, a new biorefinery strategy was used, consisting of enzymatic transesterification employing a branched 2-ethylhexanol (EH) chain alcohol. The suggested biorefinery approach utilizes an integrated process to produce jojobyl alcohols (JAs) mixture (11-eicosenol, 13-docosenol, and 15-tetracosenol) as the principal product for pharmaceutical applications. Since it meets the European Biodiesel Standard EN 14214 in all tested aspect with the exemption of the viscosity, the remaining fraction of fatty acid ethyl-hexyl esters (FAEHEs) could be a potential alternative to traditional fuels. Factorial design (FD) and response surface methodology (RSM) were used to investigate and improve the effects of variables such as temperature and catalyst concentration on the production of both fractions. The derived models can be used to estimate the best operating parameters for an up-scaled industrial process with the least number of tests possible, resulting in cost savings. However, from a technical perspective, the best feasible yield for the more valuable JAs fraction should be achieved, using a catalyst concentration of 5.7%, a temperature of 63 °C, and a 6:1 alcohol/oil molar ratio. Conversion rates of 63.5% and 36% for JAs and FAEHEs, respectively, could be produced under these conditions. The crystallization method was used to separate JAs from FAEHEs. The tetrazolium dye reduction (MTT) test was used to assess in vitro cell viability in HEK293T cells. The findings revealed that a 1 pmolL-1 oily liquid mixture of jojobyl alcohols components (cis-11-eicosenol, cis-13-docosenol, and cis-15-tetracosenol) had no influence on cell cycle progression, has no harmful impacts in the examined cells, and could be employed as a therapeutic compound. The product preparation is a green engineering process that is clean, solvent-free, and uses a highly selective catalyst to reduce water and energy utilization, as well as the integrated process's downstream processing. [ABSTRACT FROM AUTHOR]

The debate on the future of fossil fuels regained momentum in the late 1990s and has subsisted due to their negative environmental impact and the need to develop sustainable energy sources. Owing to the increasing emissions footprint, there is growing pressure to adapt to alternative clean energies in a bid to mitigate the deteriorating climatic conditions. Research on alternative energy sources is top on the agenda. As such, biofuels are now being tested as the next aviation fuel that has since attracted substantial attention. Various researchers have overtime sought to redefine the trajectory of research on biofuels starting from the feedstock varieties, evolving from sugar-rich crops to lignocellulosic or non-food-plant, to microalgae and to synthetic biological and metabolic engineering of fungal hosts. Substantial effort is directed at enhancing the biofuel storage capacity as well as deploying technologies that seek to enhance cost efficiency, towards ultimately making biofuels cost effective and commercialize-able. Despite the great potential of biofuels, the Sub- Saharan Africa contribution is still low, notwithstanding the cross cutting deterioration in climatic conditions. Therefore, following a systematic literature review approach, this study sought to ascertain the status of research on the commercialization of biofuels, conceptualization and the applied antecedents, as well as recommend policy actions and areas for further research. The findings suggest that commercialization is presently conceptualized on a few dimensions; capacity development towards large scale production and cost efficiency. Also, significant effort has been directed at migrating production from crop based feedstock to non-crop feedstock, as well as improving the storage life span of biofuels. [ABSTRACT FROM AUTHOR]

Bio-based materials have been used traditionally for millennia. Their use was overtaken in recent times by the discovery and utilization of fossil-based resources for materials and energy. However, concerns about the non-renewability of fossil resources and greenhouse gas and other emissions associated with their use have brought forth a renewed interest in using bio-based materials in recent years. The environmental advantages of bio-based materials cannot be taken for granted without a rigorous scientific assessment. Many tools based on energy, economics, and environmental impacts have been used. Life cycle assessment is one such tool developed and successfully utilized for the environmental assessment of biofuels and bioproducts. However, many methodological challenges, among other things related to system boundaries, functional units, allocation, and carbon accounting, still need further research and consideration. In this work, the related issues are summarized, and the directions for addressing them are discussed. Despite the methodological challenges in their assessment, biofuels and bioproducts show promise in terms of their environmental advantages compared to their fossil-oriented counterparts. These advantages can be further enhanced by utilizing all parts of the feedstock biomass, especially for value-added materials and chemicals via biorefineries. [ABSTRACT FROM AUTHOR]

The cultivation of microalgae for carbon capture and utilization (CCU) emerged as sustainable and effective platform to reduce GHGS and produce valuable biomass. In the study, systematic comparison of two identical algal photo-bioreactors (PBRw and PBRp), with white and purple led lights respectively, has been implemented. Carbon removals up to 98% has been obtained, with PBRp supporting enhanced cultivation conditions, higher CO2 removals and increased biomass production (up to 855 mg d−1 of dry algal biomass). The results demonstrate the potential of the proposed solutions as sustainable strategy to increase the applicability of algal photo-bioreactors for carbon capture and utilization.

Regarding the limited resources for fossil fuels and increasing global energy demands, greenhouse gas emissions, and climate change, there is a need to find alternative energy sources that are sustainable, environmentally friendly, renewable, and economically viable. In the last several decades, interest in second-generation bioethanol production from non-food lignocellulosic biomass in the form of organic residues rapidly increased because of its abundance, renewability, and low cost. Bioethanol production fits into the strategy of a circular economy and zero waste plans, and using ethanol as an alternative fuel gives the world economy a chance to become independent of the petrochemical industry, providing energy security and environmental safety. However, the conversion of biomass into ethanol is a challenging and multi-stage process because of the variation in the biochemical composition of biomass and the recalcitrance of lignin, the aromatic component of lignocellulose. Therefore, the commercial production of cellulosic ethanol has not yet become well-received commercially, being hampered by high research and production costs, and substantial effort is needed to make it more widespread and profitable. This review summarises the state of the art in bioethanol production from lignocellulosic biomass, highlights the most challenging steps of the process, including pretreatment stages required to fragment biomass components and further enzymatic hydrolysis and fermentation, presents the most recent technological advances to overcome the challenges and high costs, and discusses future perspectives of second-generation biorefineries. [ABSTRACT FROM AUTHOR]

Renewable alternatives to fossil fuels are now a worldwide effort, and biofuels can play an essential role in a sustainable energy matrix. The great potential of lignocellulosic biomass as feedstock for bioethanol production has been underexplored due to technological barriers and the costs involved. However, a new chapter in this history has been written recently after eight different biomass-to-ethanol processes achieved the industrial scale, leading bioethanol technologies to a new step of maturity due to challenges faced and lessons learned. The pretreatment of biomass has been recognized as the most complex step in the cellulosic ethanol production processes and the reason for the failure of some industrial initiatives. Pretreatment represents an essential process to prepare lignocellulosic material for subsequent hydrolysis and fermentation, and this review aims to describe the early and recent efforts to scale-up pretreatment systems and the current challenges of pretreatment operations. Since the early 2010s, a global running for cellulosic ethanol resulted in eight industrial facilities around the world; agricultural residues like corn stover, corn cob, wheat straw, sugarcane bagasse, and sugarcane straw were used by POET-DSM, Raízen, Beta Renewables, GranBio, Abengoa, DuPont, Clariant, and Longlive Bio-tech as feedstock for bioethanol production. Pretreatment technologies, including diluted acid, steam explosion, dilute ammonia, and mechanical refining, were then experienced industrially through batch or continuous systems performed in one or two conversion stages. The pretreatment systems employed by each cellulosic biorefinery are analyzed in this review, and the process conditions and strategies applied are discussed based on public information available. Furthermore, a historical background of the early developments of acid hydrolysis of cellulose and the transition to the modern pretreatment concept is provided. Typical batch reactors employed during the 1900s were replaced by continuous reactors aiming for high productivity. An overview of digesting systems used by the pulp and paper industry is explored, which were initially developed for pulping and recently adapted to perform biomass pretreatment. Special attention is paid to describing vertical and horizontal continuous digesters and mechanical disc refiners, the leading equipment used in industrial pretreatment systems. Additionally, current pretreatment challenges are discussed based on pilot and industrial experience. Biorefineries faced low throughput capacity due to unstable operation and high wear damage to equipment caused by mineral impurities. The impact of feedstock quality and preconditioning processes on pretreatment operation is also reviewed. Feedstock collection, storage, and cleaning have been considered critical operations for a successful pretreatment process; best practices from the non-wood pulping industry are analyzed, providing an important reference for biorefineries. Challenges related to pretreatment uptime, throughput, and yield are considered, and the control of residence time in horizontal continuous reactors is discussed. Finally, recent biorefinery experiences resulted in significant progress for industrial pretreatment's learning curve; this review contributes to consolidating the knowledge generated by these pioneer initiatives while this unique technology continues to evolve. • Review of the leading industrial pretreatment technologies for cellulosic ethanol. • Background of the early developments to scale-up biomass conversion systems. • Description of the recent worldwide industrial pretreatment initiatives. • Review of the best practices from the non-wood pulping industry. • Discussion of the challenges and lessons from industrial pretreatment operations. [ABSTRACT FROM AUTHOR]

[Display omitted] • A two-step process for biofuel production from EHL is investigated. • Complete EHL liquefaction achieves via non-catalytic solvolysis step. • The interaction between EHL and solvent is revealed. • Liquid products are converted into biofuels via catalytic upgrading. • Solvent reforming reactions provided hydrogen for the upgrading process. Enzymatic hydrolysis lignin (EHL) is a large-scale industrial waste generated from the bio-ethanol production process. Its complex and heterogeneous nature as well as its low solubility in common solvents, has posed a persistent barrier to its effective utilization. Here, EHL was converted into biofuel through a two-step process, involving non-catalytic solvolysis followed by catalytic product upgrading. The non-catalytic solvolysis step achieved complete EHL liquefaction in a mixture of isopropanol and H 2 O without char formation. In this step, H 2 O disrupts the hydrogen bonds in EHL and isopropanol break π-π stacking interactions between the aromatic rings in EHL·H 2 O also enhances EHL depolymerization, while isopropanol, as a hydrogen donor solvent, provides hydrogen that stabilizes active intermediates. In the catalytic product upgrading step, the liquid product of the first step was transformed into biofuels rich in cycloalkanes, arenes and alkylphenols, with a total carbon yield of 45.6 %. Isopropanol-H 2 O reforming reactions provided hydrogen for the upgrading process, avoiding the introduction of H 2. This work demonstrates an effective approach for converting EHL into biofuels. [ABSTRACT FROM AUTHOR]

In oil processing industry, large number of oilseed cakes remains after the extraction of oil. Oilseed cakes and meals are the residues would act as valuable feeds for livestock as it is rich in protein. These agricultural residues serve as a major valuable feedstock for cattle and used for the production of value-added products such as biogas, biofuel, biopolymer, antibiotics, enzymes, etc. The usage of oilseed cake as raw material would reduce environmental pollution as well as the production cost. This can be served as a potential solution to overcome nutritional problems in animals by enriching the nutrition using appropriate technologies. As the world moving towards sustainable fuel and chemical synthesis using renewable resources deemed as second-generation biofuel feedstock rather than fossil fuels, these non-edible oilseed cakes are used to produce biofuels with an integrated biorefinery perspective. The oilseed cakes plays vital role in the area of enzyme and fermentation technology. The fermentation process using fungi could act as relatively low-cost appropriate technology for upgrading nutrients in oilseed cakes. Oilseed cakes are rich in fibre and have a high concentration of non-starch polysaccharides (NSP) such as cellulose and hemicellulose (Xylan). Lipase and alpha-amylase are the two most essential enzymes produces by the oilseed cake. This review focuses on exploiting the various oilseed cakes and their commercial utilization by implementing various biotechnological approaches. [ J Adv Biotechnol Exp Ther 2021; 4(3.000): 376-387]

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 the physicochemical properties was evaluated. It was found that lignocellulosic components were not significantly affected by the pretreatment, while the 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 CS through an increase in glucose and xylose yields by 134–212% and 214–294%, respectively, when using Trichoderma longibrachiatum cellulase. The highest sugar content was obtained from CS extruded under 400 g total solids per liter and 200 rpm. The energy efficiency of the pretreatment was also assessed and was found to be maximal at 400 g total solids per liter and 200 rpm. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The European Union has recommended that about 10–50% of the global energy requirement should be supplemented by waste biomass resources by 2050 in order to achieve the objective of having net-zero-emission economies. This has led to intensive research being conducted on developing appropriate biofuel production technologies using advanced or integrated systems to tackle local, national, and global energy challenges using waste feedstock. Researchers have realized the potential of microbes (e.g., yeast strains) for bioenergy production. For this paper, both non-oleaginous and oleaginous yeasts were reviewed, with a specific focus being placed on their diversity in metabolism and tolerance to the various challenges that arise from the use of waste feedstock and influence bioprocessing. Gathering in-depth knowledge and information on yeast metabolism has paved the way for newer and better technologies to employ them for consolidated biorefineries to not only produce biofuels but also to cut down process expenses and decrease the risks of net carbon emissions. The rationale for using yeast strains improved by metabolic engineering and genetic manipulation that can substantially meet the challenges of alternate fuel resources is also described in this paper. This literature review presents the advantages and disadvantages of yeast-based biofuel production and highlights the advancements in technologies and how they contrast to conventional methods. Over the last decade, scientific publications have endorsed the idea of biorefineries for environmentally friendly, cost-effective, and sustainable biofuel production.

An integrated bioprocessing approach was applied to enhance energy recovery from the biodegradable fraction of municipal solid waste (BFMSW). Clostridium acetobutylicum and Enterobacter aerogenes with complementary characteristics were cocultivated for coproduction of hydrogen, 2,3-butanediol, and acetone-butanol-ethanol (ABE). Following the fermentation process, the remaining solids were used for biomethane production. The BFMSW was first subjected to ethanolic organosolv pretreatment and then enzymatic cellulose and hemicellulose hydrolysis at 5 and 8% solid loadings. The glucose (328 g/kg raw BFMSW), xylose (37.8 g/kg raw BFMSW), and starch (152.1 g/kg raw BFMSW) portions of the pretreated BFMSW hydrolysate with 5% solid loading were cofermented to hydrogen (162.8 L/kg raw BFMSW), 2,3-butanediol (42.5 g/kg raw BFMSW), butanol (121.9 g/kg raw BFMSW), ethanol (38.9 g/kg raw BFMSW), and acetone (45.2 g/kg raw BFMSW) by the coculture, and subsequently, the residual unfermented solids were further digested to biomethane (31.7 L/kg raw BFMSW). From the bioenergy perspective, 311.8 mL gasoline equivalent (10 MJ energy) was obtained from each kg of raw BFMSW, indicating the potential of the integrated fermentation-anaerobic digestion bioprocess for biofuels production from the zero-cost substrate. [Display omitted] [ABSTRACT FROM AUTHOR]

To meet the demands of growing population and for continuous technological advancement, the modern world requires to adapt the concept of circular economy for maximum utilization of resources, low waste generation and their recycling. The plant biomass is an abundant source of renewable energy and can be crucial in generation of various value-added products. They can act as an alternative to fossil fuels, eliminating the risk of energy shortage and environment pollution considering its abundance and environment friendly nature. The lignocellulosic source of plant biomass is a prominent candidate since it is considered as a waste though large amounts of aromatic molecules and carbohydrates are trapped in its structural components. These components can be exploited to generated numerous compounds of value via biorefinery based approach which benefit both in terms of economic and environmental pollution reduction. [ABSTRACT FROM AUTHOR]