Challenges and Future Perspectives of Promising Biotechnologies for Lignocellulosic Biorefinery

Liu, Yansong; Tang, Yunhan; Gao, Haiyan; Zhang, Wenming; Jiang, Yujia; Xin, Fengxue; Jiang, Min

doi:10.3390/molecules26175411

Cited by 51 publications

(26 citation statements)

References 112 publications

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“…are main source of cellulase enzyme production at industrial scale. T. reesei has higher cellulase content but due to lack of β-glucosidase production co-culture with A. phoenicis gave a 2.5-fold increase β-glucosidase production [ 185 ]. In a different investigation, repertoire of proteins in the secretome of a catabolite repressor-deficient strain of Penicillium funiculosum , PfMig1 88, was successfully evaluated to enhance the saccharification of sugarcane bagasse [ 186 ].…”

Section: Recent Metabolic Advances In Microorganism For Biofuel Produ...mentioning

confidence: 99%

Recent advances in metabolic engineering of microorganisms for advancing lignocellulose-derived biofuels

et al. 2022

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Combating climate change and ensuring energy supply to a rapidly growing global population has highlighted the need to replace petroleum fuels with clean, and sustainable renewable fuels. Biofuels offer a solution to safeguard energy security with reduced ecological footprint and process economics. Over the past years, lignocellulosic biomass has become the most preferred raw material for the production of biofuels, such as fuel, alcohol, biodiesel, and biohydrogen. However, the cost-effective conversion of lignocellulose into biofuels remains an unsolved challenge at the industrial scale. Recently, intensive efforts have been made in lignocellulose feedstock and microbial engineering to address this problem. By improving the biological pathways leading to the polysaccharide, lignin, and lipid biosynthesis, limited success has been achieved, and still needs to improve sustainable biofuel production. Impressive success is being achieved by the retouring metabolic pathways of different microbial hosts. Several robust phenotypes, mostly from bacteria and yeast domains, have been successfully constructed with improved substrate spectrum, product yield and sturdiness against hydrolysate toxins. Cyanobacteria is also being explored for metabolic advancement in recent years, however, it also remained underdeveloped to generate commercialized biofuels. The bacterium Escherichia coli and yeast Saccharomyces cerevisiae strains are also being engineered to have cell surfaces displaying hydrolytic enzymes, which holds much promise for near-term scale-up and biorefinery use. Looking forward, future advances to achieve economically feasible production of lignocellulosic-based biofuels with special focus on designing more efficient metabolic pathways coupled with screening, and engineering of novel enzymes.

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Section: Recent Metabolic Advances In Microorganism For Biofuel Produ...mentioning

confidence: 99%

Recent advances in metabolic engineering of microorganisms for advancing lignocellulose-derived biofuels

et al. 2022

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“…Therefore, elucidating microbial depolymerization of lignin, as well as the metabolism of aromatic subunits, could unveil mechanisms for degrading synthetic polymers. Lignin-modifying enzymes act by non-specific, oxidative mechanisms, that trigger and accelerate reactive oxygen chain reactions where free radicals decompose lignin and include laccases, lignin peroxidases, manganese peroxidases, dye-decolourizing peroxidases, versatile peroxidases, unspecific peroxidases, and laccases ( Yang et al, 2013a ; Karich et al, 2017 ; Chukwuma et al, 2020 ; Liu et al, 2021 ; Zhuo and Fan, 2021 ; Dhagat and Jujjavarapu, 2022 ). Laccases (EC 1.10.3.2) are multicopper oxidases that use O 2 as electron acceptor for oxidizing phenolic substrates, though having redox potentials (0.5–1.0 V) not strong enough to oxidize non-phenolic subunits.…”

Section: Microbial Depolymerization Of Plastics Trough Pathways For D...mentioning

confidence: 99%

“…For instance, lytic polysaccharide monooxygenases (LPMOs, EC 1.14.99.53–56) reduce Cu 2+ to Cu + using exogenous electrons, then reacting with O 2 to form a copper–superoxide complex that deconstruct crystalline cellulose. Such activity split apart the microfibrils, releasing oxidized carbohydrates, and providing access to cellulases (as glycoside hydrolases, GHs) that catalyze the hydrolysis of glycosidic bonds ( Vaaje-Kolstad et al, 2010 ; Bertini et al, 2018 ; Frommhagen et al, 2018a , b ; Song et al, 2018 ; Liu et al, 2021 ). For not having substrate specificity, LPMOs may bind and depolymerize other polysaccharidic polymers, such as chitin, xylan, and hemicellulose ( Vaaje-Kolstad et al, 2010 ; Agger et al, 2014 ; Simmons et al, 2017 ).…”

Section: Microbial Depolymerization Of Plastics Trough Pathways For D...mentioning

confidence: 99%

“…Bacterial diversity predicted from metagenome sequences is lower than other herbivorous insects, being hypothesized to be functionally related with nutrient cycling, biofilm formation, plant degradation and detoxification, although the significance of these pathways are yet to be verified ( Aylward et al, 2014 ; Barcoto et al, 2020 ; Francoeur et al, 2020 ). Of interest for bioremediation, the microbiota abundantly encode for genes participating in pathways for degradation of polycyclic aromatic hydrocarbons, xylene, benzoate and fluorobenzoate, ethylbenzene, styrene, cytochrome P450, chloroalkane and chloroalkene, dioxin, and naphthalene ( Kirk et al, 1992 ; Noman et al, 2019 ; Barcoto et al, 2020 ; Chukwuma et al, 2020 ; Liu et al, 2021 ; Dhagat and Jujjavarapu, 2022 ). That insect fungiculture is often associated with Pseudomonas -enriched communities is noteworthy, since this biofilm-forming genus is reported as degrader of several xenobiotic pollutants, as PE, PET, PP, pesticides, petroleum-derived hydrocarbons, and phenols.…”

Section: What Biotechnology Could Learn From Insect Fungiculture?mentioning

confidence: 99%

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Lessons From Insect Fungiculture: From Microbial Ecology to Plastics Degradation

Barcoto

Rodrigues

2022

Front. Microbiol.

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Anthropogenic activities have extensively transformed the biosphere by extracting and disposing of resources, crossing boundaries of planetary threat while causing a global crisis of waste overload. Despite fundamental differences regarding structure and recalcitrance, lignocellulose and plastic polymers share physical-chemical properties to some extent, that include carbon skeletons with similar chemical bonds, hydrophobic properties, amorphous and crystalline regions. Microbial strategies for metabolizing recalcitrant polymers have been selected and optimized through evolution, thus understanding natural processes for lignocellulose modification could aid the challenge of dealing with the recalcitrant human-made polymers spread worldwide. We propose to look for inspiration in the charismatic fungal-growing insects to understand multipartite degradation of plant polymers. Independently evolved in diverse insect lineages, fungiculture embraces passive or active fungal cultivation for food, protection, and structural purposes. We consider there is much to learn from these symbioses, in special from the community-level degradation of recalcitrant biomass and defensive metabolites. Microbial plant-degrading systems at the core of insect fungicultures could be promising candidates for degrading synthetic plastics. Here, we first compare the degradation of lignocellulose and plastic polymers, with emphasis in the overlapping microbial players and enzymatic activities between these processes. Second, we review the literature on diverse insect fungiculture systems, focusing on features that, while supporting insects’ ecology and evolution, could also be applied in biotechnological processes. Third, taking lessons from these microbial communities, we suggest multidisciplinary strategies to identify microbial degraders, degrading enzymes and pathways, as well as microbial interactions and interdependencies. Spanning from multiomics to spectroscopy, microscopy, stable isotopes probing, enrichment microcosmos, and synthetic communities, these strategies would allow for a systemic understanding of the fungiculture ecology, driving to application possibilities. Detailing how the metabolic landscape is entangled to achieve ecological success could inspire sustainable efforts for mitigating the current environmental crisis.

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“…However, lignocellulose has innate complexity and recalcitrance to biodegradation. In natural environments, effective plant biomass decay is obtained by synergistic activity of complex microbial communities (Auer et al, 2017;Liu et al, 2021;Rajeswari et al, 2021). No natural cellulolytic microorganism isolated so far can efficiently produce high-value compounds at a scale required for commercialization.…”

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confidence: 99%

Editorial: Microorganisms for Consolidated 2nd Generation Biorefining

2022

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Editorial on the Research Topic Microorganisms for Consolidated 2nd Generation BiorefiningIn the last few decades, lignocellulosic biomass has attracted substantial interest as a feedstock for fermentative production of fuels and other commodity chemicals due to its wide availability and low cost (Sims et al., 2010). However, lignocellulose has innate complexity and recalcitrance to biodegradation. In natural environments, effective plant biomass decay is obtained by synergistic activity of complex microbial communities (Auer et al., 2017;Liu et al., 2021;Rajeswari et al., 2021). No natural cellulolytic microorganism isolated so far can efficiently produce high-value compounds at a scale required for commercialization. On an industrial level, this traditionally requires complex process configurations, namely the need for physical and/or chemical pre-treatment (to lower biomass recalcitrance) and multiple bioreactors dedicated to cellulase production and/or biomass saccharification and/or soluble sugar fermentation (Lynd et al., 2002). The requirement for multiple process steps seriously threatens economic viability of 2nd generation biorefining processes. The most challenging barriers to developing cost-sustainable lignocellulose biorefining process include:(1) the need for costly biomass pre-treatment which may additionally generate compounds that inhibit fermenting microorganisms; (2) dependence on high loads of expensive cellulase mixtures for biomass saccharification; and (3) issues in efficient co-fermentation of hexose and pentose sugars (e.g., because of carbon catabolite repression). Substantial research efforts have been devoted to develop consolidated bioprocessing (CBP) of lignocellulose to high-value products without the use of exogenous enzymes, namely single-pot fermentation. Motivation for this highly ambitious fermentative strategy is based on the dramatic reduction of process cost (i.e., 40-77%) with respect to traditional (less consolidated) configurations (Lynd et al., 2005(Lynd et al., , 2008. The studies included in this Research Topic touch on some key research areas for achieving CBP, as summarized below.A variety of physical and/or chemical pre-treatment methods have been developed to decrease lignocellulose recalcitrance to biodegradation through separation of biomass components (e.g., cellulose, hemicellulose and lignin), improvement of accessibility to enzymes and microorganisms, and reduction of crystallinity (Zhou and Tian, 2022). However, these processes are typically cost challenging and, depending on the technology used, subject to the formation of compounds Publisher's Note: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

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Challenges and Future Perspectives of Promising Biotechnologies for Lignocellulosic Biorefinery

Cited by 51 publications

References 112 publications

Recent advances in metabolic engineering of microorganisms for advancing lignocellulose-derived biofuels

Recent advances in metabolic engineering of microorganisms for advancing lignocellulose-derived biofuels

Lessons From Insect Fungiculture: From Microbial Ecology to Plastics Degradation

Editorial: Microorganisms for Consolidated 2nd Generation Biorefining

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