The effects of model aromatic lignin compounds on growth and lipid accumulation of Rhodococcus rhodochrous

Shields-Menard, Sara A.; Amirsadeghi, Marta; Green, Magan; Womack, Erika D.; Sparks, Darrell; Blake, Jacqui; Edelmann, Mariola J.; Ding, Xuan; Sukhbaatar, Badamkhand; Hernández, Rafael; Donaldson, Janet R.; French, Todd

doi:10.1016/j.ibiod.2017.03.023

Cited by 49 publications

(13 citation statements)

References 45 publications

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“…Rhodococcus is a genus of mycolic acid-producing Actinobacteria that catabolize a wide variety of aromatic compounds (Yam et al, 2010), including phenols (Kolomytseva et al, 2007; Gröning et al, 2014). These bacteria also have considerable potential as biocatalysts for the industrial production of compounds ranging from nitriles to steroids and high-value lipids (Alvarez et al, 1996; Round et al, 2017; Shields-Menard et al, 2017; Sengupta et al, 2019). In Rhodococcus , phenol catabolism is initiated by a two-component flavin-dependent monooxygenase (PheA1A2; Saa et al, 2010) to generate a catechol.…”

Section: Introductionmentioning

confidence: 99%

Catabolism of Alkylphenols in Rhodococcus via a Meta-Cleavage Pathway Associated With Genomic Islands

et al. 2019

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The 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 isolated Rhodococcus rhodochrous EP4 on 4-ethylphenol and applied genomic and transcriptomic approaches to elucidate alkylphenol catabolism in EP4 and Rhodococcus jostii RHA1. RNA-Seq and RT-qPCR revealed a pathway encoded by the aphABCDEFGHIQRS genes that degrades 4-ethylphenol via the meta- cleavage of 4-ethylcatechol. This process was initiated by a two-component alkylphenol hydroxylase, encoded by the aphAB genes, which were upregulated ~3,000-fold. Purified AphAB from EP4 had highest specific activity for 4-ethylphenol and 4-propylphenol (~2,000 U/mg) but did not detectably transform phenol. Nevertheless, a Δ aphA mutant in RHA1 grew on 4-ethylphenol by compensatory upregulation of phenol hydroxylase genes ( pheA1-3 ). Deletion of aphC , encoding an extradiol dioxygenase, prevented growth on 4-alkylphenols but not phenol. Disruption of pcaL in the β-ketoadipate pathway prevented growth on phenol but not 4-alkylphenols. Thus, 4-alkylphenols are catabolized exclusively via meta- cleavage in rhodococci while phenol is subject to ortho- cleavage. A putative genomic island encoding aph genes was 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.

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Section: Introductionmentioning

confidence: 99%

Catabolism of Alkylphenols in Rhodococcus via a Meta-Cleavage Pathway Associated With Genomic Islands

et al. 2019

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“…Rhodococcus species has been applied for converting lignin and aromatics to lipids; the 4-hydroxybenzoic acid and vanillic acid to triacylglycerols by R. opacus DSM 1069 and PD630 strains, which accumulated lipid about 20% of the dry cell weight (DCW) under nitrogen-limiting conditions [ 126 ]. R. rhodochrous could produce more lipids when cultivated with aromatic compounds and glucose [ 127 ]. The alkali, kraft, and ethanol organosolv lignin have also been applied for lipid production with bacteria catalysis.…”

Section: Bioconverting Lignin To Value-added Bioproducts By Microbial Catalysis and Metabolic Engineeringmentioning

confidence: 99%

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

Weng

Peng

Han

2021

Biotechnol Biofuels

165

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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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“…For example, when p -hydroxybenzoic acid or vanillic acid was applied as the sole carbon source, both R. opacus PD630 and R. opacus DSM 1069 can survive well on these two lignin model monomers and accumulate approximately 20% of DCW as lipids under nitrogen limiting conditions [98]. Further studies demonstrate that blending lignin-based aromatics with glucose increased lipid contents considerably [99].…”

Section: Application Of Multiple Metabolic Pathways For Lignin Valorimentioning

confidence: 99%

Recent advances in lignin valorization with bacterial cultures: microorganisms, metabolic pathways, and bio-products

Lei²,

Zhai

et al. 2019

Biotechnol Biofuels

211

119

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Lignin is the most abundant aromatic substrate on Earth and its valorization technologies are still under developed. Depolymerization and fragmentation are the predominant preparatory strategies for valorization of lignin to chemicals and fuels. However, due to the structural heterogeneity of lignin, depolymerization and fragmentation typically result in diverse product species, which require extensive separation and purification procedures to obtain target products. For lignin valorization, bacterial-based systems have attracted increasing attention because of their diverse metabolisms, which can be used to funnel multiple lignin-based compounds into specific target products. Here, recent advances in lignin valorization using bacteria are critically reviewed, including lignin-degrading bacteria that are able to degrade lignin and use lignin-associated aromatics, various associated metabolic pathways, and application of bacterial cultures for lignin valorization. This review will provide insight into the recent breakthroughs and future trends of lignin valorization based on bacterial systems.

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The effects of model aromatic lignin compounds on growth and lipid accumulation of Rhodococcus rhodochrous

Abstract: 2017-08-25T16:28:34

Cited by 49 publications

References 45 publications

Catabolism of Alkylphenols in Rhodococcus via a Meta-Cleavage Pathway Associated With Genomic Islands

Catabolism of Alkylphenols in Rhodococcus via a Meta-Cleavage Pathway Associated With Genomic Islands

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

Recent advances in lignin valorization with bacterial cultures: microorganisms, metabolic pathways, and bio-products

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