Towards lignin consolidated bioprocessing: simultaneous lignin depolymerization and product generation by bacteria

2015 ◽  
Vol 17 (11) ◽  
pp. 4951-4967 ◽  
Author(s):  
Davinia Salvachúa ◽  
Eric M. Karp ◽  
Claire T. Nimlos ◽  
Derek R. Vardon ◽  
Gregg T. Beckham
Keyword(s):  
Aromatic Compounds ◽  
Consolidated Bioprocessing ◽  
Product Generation ◽  
Lignin Depolymerization

Lignin Consolidated Bioprocessing utilizes microbes that simultaneously depolymerize lignin and convert the resulting aromatic compounds to fuel and chemical precursors.

scholarly journals Recent Advances in Applications of Acidophilic Fungal Microbes for Bio-Chemicals

2018 ◽  
Author(s):  
Rehman Javaid ◽  
Aqsa Sabir ◽  
Nadeem Sheikh ◽  
Muhammad Ferhan
Keyword(s):  
Carbon Fibers ◽  
Aromatic Compounds ◽  
Fossil Fuels ◽  
Value Added ◽  
Environmental Issue ◽  
Enzymatic Conversion ◽  
Environment Friendly ◽  
Phenyl Propanoid ◽  
Lignin Peroxidases ◽  
Lignin Depolymerization

The processing of fossil fuels is the major environmental issue today which should be lessen. Biomass is gaining much interest these days as an alternate to energy generation. Lignocellulosic biomass (cellulose, hemicellulose and lignin) is abundant and has been used for a variety of purposes. Among them, the lignin polymer having phenyl-propanoid subunits linked together through C-C bonds or ether linkages, can produce numerous chemicals. It can be depolymerized by microbial activity together with certain enzymes (laccases and peroxidases). Both acetic acid and formic acid production by certain fungi contribute significantly to lignin depolymerization. Natural organic acids production by fungi has many key roles in nature that are strictly dependent upon organic acid producing fungus type. Fungal enzymatic conversion of lignocellulosic is beneficial over other physiochemical processes. Laccases, the copper containing proteins oxidize a broad spectrum of inorganic as well as organic compounds but most specifically phenolic compounds by radical catalyzed mechanism. Similarly, lignin peroxidases (LiP), the heme containing proteins perform a vital part in oxidizing a wide variety of aromatic compounds with H2O2. Lignin depolymerization yields value-added compounds, the important ones are BTX (Benzene, Xylene and Toluene) and phenols as well as certain polymers like polyurethane and carbon fibers. Thus, this review will provide a concept that biological modifications of lignin using acidophilic microbes can generate certain value added and environment friendly chemicals.

scholarly journals Recent Advances in Applications of Acidophilic Fungi to Produce Chemicals

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 786 ◽  
Author(s):  
Rehman Javaid ◽  
Aqsa Sabir ◽  
Nadeem Sheikh ◽  
Muhammad Ferhan
Keyword(s):  
Lignocellulosic Biomass ◽  
Carbon Fibers ◽  
Aromatic Compounds ◽  
Fossil Fuels ◽  
Value Added ◽  
Environmental Issue ◽  
Phenyl Propanoid ◽  
Biological Conversion ◽  
Lignin Peroxidases ◽  
Lignin Depolymerization

Processing of fossil fuels is the major environmental issue today. Biomass utilization for the production of chemicals presents an alternative to simple energy generation by burning. Lignocellulosic biomass (cellulose, hemicellulose and lignin) is abundant and has been used for variety of purposes. Among them, lignin polymer having phenyl-propanoid subunits linked together either through C-C bonds or ether linkages can produce chemicals. It can be depolymerized by fungi using their enzyme machinery (laccases and peroxidases). Both acetic acid and formic acid production by certain fungi contribute significantly to lignin depolymerization. Fungal natural organic acids production is thought to have many key roles in nature depending upon the type of fungi producing them. Biological conversion of lignocellulosic biomass is beneficial over physiochemical processes. Laccases, copper containing proteins oxidize a broad spectrum of inorganic as well as organic compounds but most specifically phenolic compounds by radical catalyzed mechanism. Similarly, lignin peroxidases (LiP), heme containing proteins perform a vital part in oxidizing a wide variety of aromatic compounds with H2O2. Lignin depolymerization yields value-added compounds, the important ones are aromatics and phenols as well as certain polymers like polyurethane and carbon fibers. Thus, this review will provide a concept that biological modifications of lignin using acidophilic fungi can generate certain value added and environmentally friendly chemicals.

scholarly journals Recent Advances in Applications of Acidophilic Fungal Microbes for Bio-Chemicals

2018 ◽  
Author(s):  
Rehman Javaid ◽  
Aqsa Sabir ◽  
Nadeem Sheikh ◽  
Muhammad Ferhan
Keyword(s):  
Acetic Acid ◽  
Aromatic Compounds ◽  
Value Added ◽  
Enzymatic Conversion ◽  
Environment Friendly ◽  
Lignocellulosic Feedstock ◽  
Phenyl Propanoid ◽  
Inorganic As ◽  
Lignin Peroxidases ◽  
Lignin Depolymerization

Lignocellulosic feedstock (cellulose, hemicellulose and lignin) has been used for a variety of purposes. Among them, lignin can produce value-added chemicals having phenyl-propanoid subunits known as core lignin, possessing either C-C bonds or ether linkages. It can be depolymerized by microbial activity together with certain enzymes (laccases and peroxidases). Both acetic acid and formic acid production by certain fungi contribute significantly to lignin depolymerization. Natural organic acids production by fungi has many key roles in nature that are strictly dependent upon organic acid producing fungus type. Enzymatic conversion of lignocellulosic is beneficial over other physiochemical processes. Laccases, the copper containing proteins oxidize a broad spectrum of inorganic as well as organic compounds but most specifically phenolic compounds by radical catalyzed mechanism. Similarly, lignin peroxidases (LiP), the heme containing proteins perform a vital part in oxidizing a wide variety of aromatic compounds with H2O2. Lignin depolymerization yields polyaromatics, the important ones are BTX (Benzene, Xylene and Toluene), found in several different configurations. However, most modern aromatics complexes enhance the production of p-xylene, benzene and sometimes o-xylene respectively. Thus, this review will provide a concept that chemical and biological modifications of lignin yield certain value added and environment friendly chemicals.

Low temperature lignin depolymerization to aromatic compounds with a redox couple catalyst

Fuel ◽  
2020 ◽  
Vol 281 ◽  
pp. 118799
Author(s):  
Zhe Zhang ◽  
Parikshit Gogoi ◽  
Zhishuai Geng ◽  
Xinliang Liu ◽  
Xu Du
Keyword(s):  
Low Temperature ◽  
Aromatic Compounds ◽  
Redox Couple ◽  
Lignin Depolymerization

scholarly journals Catabolism of alkylphenols inRhodococcusvia ameta-cleavage pathway associated with genomic islands

2019 ◽  
Author(s):  
David J. Levy-Booth ◽  
Morgan M. Fetherolf ◽  
Gordon Stewart ◽  
Jie Liu ◽  
Lindsay D. Eltis ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Plant Biomass ◽  
Specific Activity ◽  
Industrial Applications ◽  
Genomic Islands ◽  
Phylogenomic Analysis ◽  
Rhodococcus Rhodochrous ◽  
Extradiol Dioxygenase ◽  
Lignin Depolymerization ◽  
Rhodococcus Jostii

AbstractThe bacterial catabolism of aromatic compounds has considerable promise to convert lignin depolymerization products to commercial chemicals. Alkylphenols are a key class of depolymerization products whose catabolism is not well elucidated. We isolatedRhodococcus rhodochrousEP4 on 4-ethylphenol and applied genomic and transcriptomic approaches to elucidate alkylphenol catabolism in EP4 andRhodococcus jostiiRHA1. RNA-Seq and RT-qPCR revealed a pathway encoded by theaphABCDEFGHIQRSgenes that degrades 4-ethylphenol via themeta-cleavage of 4-ethylcatechol. This process was initiated by a two-component alkylphenol hydroxylase, encoded by theaphABgenes, which were up-regulated ~3,000-fold. Purified AphAB from EP4 had highest specific activity for 4-ethylphenol and 4-propylphenol (~2000 U/mg) but did not detectably transform phenol. Nevertheless, a ΔaphAmutant in RHA1 grew on 4-ethylphenol by compensatory up-regulation of phenol hydroxylase genes (pheA1-3). Deletion ofaphC, encoding an extradiol dioxygenase, prevented growth on 4-alkylphenols but not phenol. Disruption ofpcaLin the β-ketoadipate pathway prevented growth on phenol but not 4-alkylphenols. Thus, 4-ethylphenol and 4-propylphenol are catabolized exclusively viameta-cleavage in rhodococci while phenol is subject toortho-cleavage. Putative genomic islands encodingaphgeneswere identified in EP4 and several other rhodococci. Overall, this study identifies a 4-alkylphenol pathway in rhodococci, demonstrates key enzymes involved, and presents evidence that the pathway is encoded in a genomic island. These advances are of particular importance for wide-ranging industrial applications of rhodococci, including upgrading of lignocellulose biomass.ImportanceElucidation of bacterial alkylphenol catabolism is important for the development of biotechnologies to upgrade the lignin component of plant biomass. We isolated a new strain,Rhodococcus rhodochrousEP4, on 4-ethylphenol, an alkylphenol that occurs in lignin-derived streams, including reductive catalytic fractionation products of corn stover. We further demonstrated its degradation via ameta-cleavage pathway (Aph) with transcriptomics. A new class of Actinobacterial hydroxylase, AphAB, acts specifically on alkylphenols. Phylogenomic analysis indicated that theaphgenes occur on putative genomic islands in several rhodococcal strains. These genes were identified in the genetically-tractable strainRhodococcus jostiiRHA1. Strains missing this element cannot metabolise 4-ethylphenol and 4-propylphenol. Overall, we advanced the understanding of how aromatic compounds are degraded by environmental bacteria and identified enzymes that can be employed in the transition away from petro-chemicals towards renewable alternatives.

scholarly journals Investigating (Pseudo)-Heterogeneous Pd-Catalysts for Kraft Lignin Depolymerization under Mild Aqueous Basic Conditions

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1311
Author(s):  
Dolorès Bourbiaux ◽  
Yu Xu ◽  
Laurence Burel ◽  
Firat Goc ◽  
Pascal Fongarland ◽  
...  
Keyword(s):  
Energy Source ◽  
Aromatic Compounds ◽  
Palladium Catalysts ◽  
Paper Industry ◽  
Kraft Lignin ◽  
Synthetic Methods ◽  
Pd Catalysts ◽  
Renewable Source ◽  
Main Components ◽  
Lignin Depolymerization

Lignin is one of the main components of lignocellulosic biomass and corresponds to the first renewable source of aromatic compounds. It is obtained as a by-product in 100 million tons per year, mainly from the paper industry, from which only 2–3% is upgraded for chemistry purposes, with the rest being used as an energy source. The richness of the functional groups in lignin makes it an attractive precursor for a wide variety of aromatic compounds. With this aim, we investigated the Pd-catalyzed depolymerization of lignin under mild oxidizing conditions (air, 150 °C, and aqueous NaOH) producing oxygenated aromatic compounds, such as vanillin, vanillic acid, and acetovanillone. Palladium catalysts were implemented following different strategies, involving nanoparticles stabilized in water, and nanoparticles were supported on TiO2. Significant conversion of lignin was observed in all cases; however, depending on the catalyst nature and the synthetic methods, differences were observed in terms of selectivity in aromatic monomers, mainly vanillin. All these aspects are discussed in detail in this report, which also provides new insights into the role that Pd-catalysts can play for the lignin depolymerization mechanism.

1679 Fatty acid profile, sensory traits, and aromatic compounds of chops from lambs fed ground woody plants as roughage in feedlot finishing diets

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 818-818
Author(s):  
K. R. Wall ◽  
C. R. Kerth ◽  
T. R. Whitney ◽  
S. B. Smith ◽  
J. L. Glasscock ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Aromatic Compounds ◽  
Woody Plants ◽  
Finishing Diets

Tandem Mass Spectrometric Evaluation of Core Structures of Aromatic Compounds after Catalytic Deoxygenation

2017 ◽  
Author(s):  
Xueming Dong
Keyword(s):  
Aromatic Compounds ◽  
Supported Catalyst ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Aromatic Rings ◽  
Tandem Mass Spectrometric ◽  
Catalytic Deoxygenation ◽  
Oxygen Atoms

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquids. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms in aromatic compounds reside outside of aromatic rings or are part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings.<br>

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