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Journal ArticleDOI

Depolymerization and conversion of lignin to value-added bioproducts by microbial and enzymatic catalysis

03 Apr 2021-Biotechnology for Biofuels (BioMed Central)-Vol. 14, Iss: 1, pp 1-22
TL;DR: In this paper, the most recent advances in degradation and conversion of lignin to value-added bioproducts catalyzed by microbes and enzymes were summarized, and new insights for future work to overcome the heterogeneity and recalcitrance of Lignin and convert it to value added products by microbial and enzymatic catalysis were proposed.
Abstract: Lignin, the most abundant renewable aromatic compound in nature, is an excellent feedstock for value-added bioproducts manufacturing; while the intrinsic heterogeneity and recalcitrance of which hindered the efficient lignin biorefinery and utilization. Compared with chemical processing, bioprocessing with microbial and enzymatic catalysis is a clean and efficient method for lignin depolymerization and conversion. Generally, lignin bioprocessing involves lignin decomposition to lignin-based aromatics via extracellular microbial enzymes and further converted to value-added bioproducts through microbial metabolism. In the review, the most recent advances in degradation and conversion of lignin to value-added bioproducts catalyzed by microbes and enzymes were summarized. The lignin-degrading microorganisms of white-rot fungi, brown-rot fungi, soft-rot fungi, and bacteria under aerobic and anaerobic conditions were comparatively analyzed. The catalytic metabolism of the microbial lignin-degrading enzymes of laccase, lignin peroxidase, manganese peroxidase, biphenyl bond cleavage enzyme, versatile peroxidase, and β-etherize was discussed. The microbial metabolic process of H-lignin, G-lignin, S-lignin based derivatives, protocatechuic acid, and catechol was reviewed. Lignin was depolymerized to lignin-derived aromatic compounds by the secreted enzymes of fungi and bacteria, and the aromatics were converted to value-added compounds through microbial catalysis and metabolic engineering. The review also proposes new insights for future work to overcome the recalcitrance of lignin and convert it to value-added bioproducts by microbial and enzymatic catalysis.

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Citations
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Journal ArticleDOI
TL;DR: In this article , the main constraints affecting industrial lignin valorization, possible solutions and future perspectives, in the light of its abundance and its potential applications reported in the scientific literature are highlighted.

75 citations

Journal ArticleDOI
TL;DR: In this paper, the most common preparation processes for converting lignin to platform chemicals and bio-fuels are fragmentation and depolymerization, which are commonly utilized for lignIN fragmentation due to their high metabolitic activity.

32 citations

Journal ArticleDOI
TL;DR: In this paper , the most common preparation processes for converting lignin to platform chemicals and bio-fuels are fragmentation and depolymerization, which are commonly utilized for lignIN fragmentation due to their high metabolitic activity.

32 citations

Journal ArticleDOI
TL;DR: A considerable escalation on the enzymatic activities obtained in a short period from the cultivation of the L. betulina or T. versicolor due to the enhanced microbial synergistic effects, providing a potential bioconversion route for the applications of lignin utilization.
Abstract: As one of the major components of lignocellulosic biomass, lignin has been considered as the most abundant renewable aromatic feedstock in the world. Comparing with thermal or catalytic strategies for lignin degradation, biological conversion is a promising approach featuring with mild conditions and diversity, and has received great attention nowadays. In this study, a consortium of white rot fungi composed of Lenzites betulina and Trametes versicolor was employed to enhance the ligninolytic enzyme activity of laccase (Lac) and manganese peroxidase (MnP) under microbial synergism. The maximum enzymatic activity of Lac and MnP was individually 18.06 U mL−1 and 13.58 U mL−1 along with a lignin degradation rate of 50% (wt/wt), which were achieved from batch cultivation of the consortium. The activities of Lac and MnP obtained from the consortium were both improved more than 40%, as compared with monocultures of L. betulina or T. versicolor under the same culture condition. The enhanced biodegradation performance was in accordance with the results observed from scanning electron microscope (SEM) of lignin samples before and after biodegradation, and secondary-ion mass spectrometry (SIMS). Finally, the analysis of heteronuclear single quantum coherence (HSQC) NMR and gas chromatography–mass spectrometry (GC–MS) provided a comprehensive product mapping of the lignin biodegradation, suggesting that the lignin has undergone depolymerization of the macromolecules, side-chain cleavage, and aromatic ring-opening reactions. Our results revealed a considerable escalation on the enzymatic activity obtained in a short period from the cultivation of the L. betulina or T. versicolor due to the enhanced microbial synergistic effects, providing a potential bioconversion route for lignin utilization.

29 citations

Journal ArticleDOI
TL;DR: In this paper , the authors focus on the simulation of the organosolv pretreatment and the optimization of feedstock delignification, sugar production, enzymatic digestibility of the cellulose fraction and quality of lignin.

19 citations

References
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Journal ArticleDOI
TL;DR: Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy.
Abstract: Biomass is an important feedstock for the renewable production of fuels, chemicals, and energy. As of 2005, over 3% of the total energy consumption in the United States was supplied by biomass, and it recently surpassed hydroelectric energy as the largest domestic source of renewable energy. Similarly, the European Union received 66.1% of its renewable energy from biomass, which thus surpassed the total combined contribution from hydropower, wind power, geothermal energy, and solar power. In addition to energy, the production of chemicals from biomass is also essential; indeed, the only renewable source of liquid transportation fuels is currently obtained from biomass.

3,644 citations

Journal ArticleDOI
TL;DR: Lignin is the generic term for a large group of aromatic polymers resulting from the oxidative combinatorial coupling of 4-hydroxyphenylpropanoids, deposited predominantly in the walls of secondarily thickened cells, making them lignin-like polymers.
Abstract: Lignin is the generic term for a large group of aromatic polymers resulting from the oxidative combinatorial coupling of 4-hydroxyphenylpropanoids ([Boerjan et al., 2003][1]; [Ralph et al., 2004][2]). These polymers are deposited predominantly in the walls of secondarily thickened cells, making them

1,956 citations

Journal ArticleDOI
TL;DR: Laccase is capable of oxidizing both phenolic and non‐phenolic moieties of lignin but that the latter is dependent on the co‐presence of primary laccase substrates.

1,296 citations

Journal ArticleDOI
TL;DR: The structure of lignin suggests that it can be a valuable source of chemicals, particularly phenolics as discussed by the authors, but it is the major challenge for converting it into value-added chemicals.
Abstract: The structure of lignin suggests that it can be a valuable source of chemicals, particularly phenolics. However, lignin depolymerization with selective bond cleavage is the major challenge for converting it into value-added chemicals. Pyrolysis (thermolysis), gasification, hydrogenolysis, chemical oxidation, and hydrolysis under supercritical conditions are the major thermochemical methods studied with regard to lignin depolymerization. Pyrolytic oil and syngases are the primary products obtained from pyrolysis and gasification. A significant amount of char is also produced during pyrolysis. Thermal treatment in a hydrogen environment seems very promising for converting lignin to liquid fuel and chemicals like phenols, while oxidation can produce phenolic aldehydes. Reaction severity, solvents, and catalysts are the factors of prime importance that control yield and composition of the product.

1,185 citations

Trending Questions (1)
What biobased products can be obtained with ligning and microorganisms?

The paper discusses the conversion of lignin to value-added bioproducts using microbial and enzymatic catalysis. It mentions the production of lignin-based aromatics, polyhydroxyalkanoates (PHAs), and dicarboxylic acids as potential biobased products.