Project description:The production of lignocellulosic-derived biofuels is a highly promising source of alternative energy, but it has been constrained by the lack of a microbial platform capable to efficiently degrade this recalcitrant material and cope with by-products that can be toxic to cells. Species that naturally grow in environments where carbon is mainly available as lignin are promising for finding new ways of removing the lignin that protects cellulose for improved conversion of lignin to fuel precursors.
2018-02-13 | GSE96828 | GEO
Project description:screen fungus for degrade lignin and cellulose
| PRJNA1092060 | ENA
Project description:Consortium able to degrade Carbon tetrachloride
| PRJNA813969 | ENA
Project description:A bacterial consortium can degrade azodye
Project description:Microarrays have become established tools for describing microbial systems, however the assessment of expression profiles for environmental microbial communities still presents unique challenges. Notably, the concentration of particular transcripts are likely very dilute relative to the pool of total RNA, and PCR-based amplification strategies are vulnerable to amplification biases and the appropriate primer selection. Thus, we apply a signal amplification approach, rather than template amplification, to analyze the expression of selected lignin-degrading enzymes in soil. Controls in the form of known amplicons and cDNA from Phanerochaete chrysosporium were included and mixed with the soil cDNA both before and after the signal amplification in order to assess the dynamic range of the microarray. We demonstrate that restored prairie soil expresses a diverse range of lignin-degrading enzymes following incubation with lignin substrate, while farmed agricultural soil does not. The mixed additions of control cDNA with soil cDNA indicate that the mixed biomass in the soil does interfere with low abundance transcript changes, nevertheless our microarray approach consistently reports the most robust signals. Keywords: comparative analysis, microbial ecology, soil microbial communities We used lignin degradation as a model process to demonstrate the use of an oligonucleotide microarray for directly detecting gene expression in soil communities using signal amplification instead of template amplification to avoid the introduction of PCR bias. In the current study, we analyzed mRNA isolated from two distinct soil microbial communities and demonstrate our ability to detect the expression of a small subset of lignin degrading genes following exposure to a lignitic substrate. We also included purified control amplicons and mixed target experiments with pure P. chrysosporium genomic cDNA to determine the level of interference from soil biomass on target hybridization.
Project description:Microarrays have become established tools for describing microbial systems, however the assessment of expression profiles for environmental microbial communities still presents unique challenges. Notably, the concentration of particular transcripts are likely very dilute relative to the pool of total RNA, and PCR-based amplification strategies are vulnerable to amplification biases and the appropriate primer selection. Thus, we apply a signal amplification approach, rather than template amplification, to analyze the expression of selected lignin-degrading enzymes in soil. Controls in the form of known amplicons and cDNA from Phanerochaete chrysosporium were included and mixed with the soil cDNA both before and after the signal amplification in order to assess the dynamic range of the microarray. We demonstrate that restored prairie soil expresses a diverse range of lignin-degrading enzymes following incubation with lignin substrate, while farmed agricultural soil does not. The mixed additions of control cDNA with soil cDNA indicate that the mixed biomass in the soil does interfere with low abundance transcript changes, nevertheless our microarray approach consistently reports the most robust signals. Keywords: comparative analysis, microbial ecology, soil microbial communities
Project description:Aromatic diketones are a major product of formic acid lignin depolymerization. Novosphingobium aromaticivorans can degrade these diketones, but the enzymes used in this process were unknown. We used RNA-Seq to identify aromatic dimer dehydrogenases as potential candidates for the initial reduction of the aromatic G-diketone, then verified this using in vitro enzyme assays.
Project description:Convergent microbial biocatalysis has emerged as a promising approach for the conversion of lignin side-streams into value-added chemicals in recent decades. However, the current knowledge of metabolic pathways directing the bioconversion of lignin-related aromatics is still limited to a few microbial species and unavailable for some of these compounds. Thus, the aim of this study was to identify the genes involved in the bioconversion of aromatic compounds in Xanthomonas citri subsp. citri 306 (X. citri 306), a bacterium belonging to a compelling yet untapped genus for studies on lignin-related aromatics metabolism. For this purpose, we used an integrative approach including genome data mining, RNA-seq, enzymology and gene knockout studies. The RNA-seq analysis revealed a total of 278 to 1464 differentially expressed genes (DEGs) in the aromatic-containing conditions compared to the control XVM2m-glucose, evidencing the importance of these compounds in modulating various physiological processes of X. citri 306 beyond the pathways related to their metabolism. Moreover, this work revealed the operon molRKAB, which plays a role in the first catabolic steps of the three main monolignols (p-coumaryl, coniferyl and sinapyl alcohols), besides showing all the enzymatic steps funneling them up to the tricarboxylic acid cycle. Additionally, the study uncovered aryl aldehyde reductases and efflux strategies that likely function to protect the pathogen from aromatics toxicity. Together, these findings enhance the current understanding of Xanthomonas metabolism and transcriptional responses to lignin-related aromatic compounds, shedding light on the diverse metabolic pathways available to enable the engineering of microbial chassis dedicated to lignin valorization.