- Title
- Biodegradation of lignocellulose biomass by faecal bacteria of marsupial animals
- Creator
- Fatema, Kaniz
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2024
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- This research contributes to the promising field of environmental biotechnology by exploring the capabilities of bacterial strains isolated from the faeces of Australian marsupials—koalas and wombats. Koalas (Phascolarctos cinereus) are very specialised herbivores that feed exclusively on eucalyptus leaves, which are rich in lignified fibre, and plant secondary metabolites, making them challenging for most animals to digest. Wombat (Vombatus ursinus) in contrast, consume a variety of lignocellulosic plant materials mainly grasses and roots. These unique dietary requirements highlight the specialised adaptations of their gut microbiomes, which include vertical microbiota transfers like pap feeding, crucial for digesting eucalyptus. Lignocellulosic biomass is a renewable and abundant resource for sustainable energy production. However, the inherent complexity of lignocellulosic materials, composed of cellulose, hemicellulose, and lignin, presents significant challenges in their conversion to usable energy forms. Effective pretreatment of biomass is essential for breaking down these complex polymers into fermentable sugars for biofuel production. The unique dietary habits of koalas and wombats, who consume lignocellulose-rich diets, suggest that their gut microbiomes could be a source of potent biocatalysts for biomass degradation. Biological methods using microorganisms for biomass pretreatment are gaining recognition for their environmental and economic advantages. This study focused on four bacterial strains, three aerobic Streptomyces sp. and one facultatively anaerobic Enterobacter sp., isolated from the faeces of koalas and wombats. These strains have exhibited promising capabilities in hydrolysing cellulose and depolymerising lignin, facilitating the conversion of complex polymers into fermentable sugars essential for biofuel production. Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Gas Chromatography-Mass Spectrometry (GC-MS) analyses confirmed the biodegradation of lignocellulosic biomass and the formation of various degradation products. FTIR analysis revealed alterations in functional groups indicative of lignin breakdown and cellulose exposure. XRD results showed changes in crystallinity, suggesting a more accessible cellulose structure for enzymatic attack. SEM images illustrated morphological changes in the biomass, including increased porosity and disruption of structural integrity, enhancing enzyme accessibility. GC-MS analysis identified a range of degradation products, including glycerol compounds and various acids, indicating the comprehensive breakdown of complex biomass components. The isolated strains produce a suite of cellulases and ligninolytic enzymes, including laccase, LiP, and MnP, that are crucial for the biodegradation of recalcitrant lignocellulosic biomass. These enzymes not only degrade complex organic pollutants but are also pivotal for a range of industrial applications including the production of biofuels and bioremediation. The novelty of this study lies in leveraging the unique gut microbiota of koalas and wombats, which are naturally adapted to break down tough plant materials, thereby offering new enzymatic tools for biotechnological applications. This study paves the way for innovative, eco-friendly solutions for biomass conversion, contributing significantly to a sustainable bioeconomy. Future research will focus on optimising the enzymatic production conditions and exploring the scalability of these bioprocesses for industrial applications, enhancing the practical utilisation of these microbial biocatalysts.
- Subject
- lignocellulose biomass; biodegradation; marsupial animals; faecal bacteria; lignin peroxidase
- Identifier
- http://hdl.handle.net/1959.13/1512557
- Identifier
- uon:56631
- Rights
- This thesis is currently under embargo and will be available from 10.10.2025. Copyright 2024 Kaniz Fatema
- Language
- eng
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