Microbial Lignin Degradation in the Environment

Steel, Bruce (2023) Microbial Lignin Degradation in the Environment. Doctoral thesis, University of East Anglia.

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Lignocellulosic biomass has attracted attention as a renewable industrial feedstock due to its abundance in nature and wide range of potential applications. Current conversion processes, such as in biofuel production, are complicated by the presence of lignin within lignocellulose. Research has identified many environmental microorganisms capable of degrading lignin, which could potentially be exploited for use in bioprocessing, however, little is known of how microorganisms, specifically bacteria, contribute towards the degradation of lignin. Therefore, the aim of this project was to explore lignin degradation in a wide range of environments and to identify the main microbial players, including key enzymes and biochemical pathways that contribute to the degradation of lignin in these environments. This was done via biochemical and molecular biological approaches, such as stable isotope probing using 13C-labelled lignin, rRNA gene amplicon sequencing, and metagenomics. In this study, we investigated microbial lignin degradation in a wide range of oxic and anoxic environments, including soil, herbivore animal faeces, compost and lake sediment. Metagenomic sequencing of the environmental samples identified distinct microbial communities with the genetic potential to activate diverse lignin degradative mechanisms. Lignin-degrading bacterial isolates from these environments and their phylogenetic characterization and ligninolytic enzyme activity analysis revealed varying utilization of oxidative enzymes by different isolates. Furthermore, gas chromatography-mass spectrometry analysis of lignin oxidised phenols from bacterial isolate cultures showed considerable variation compared to control cultures, suggesting specific and diverse lignin breakdown. These results provide new insights into microbial degradation of recalcitrant plant material in the environment.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 13 Jul 2023 10:17
Last Modified: 13 Jul 2023 10:17
URI: https://ueaeprints.uea.ac.uk/id/eprint/92597


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