Identification of genes and interactions involved in syntrophic biodegradation under methanogenic conditions
Date
2023-07
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Abstract
Biodegradation, or the breakdown of pollutants by microorganisms, occurs in many global environments. Hydrocarbon biodegradation can be carried out by a diverse range of microorganisms, such as sulfate reducing microorganisms (SRM), and methanogens. Syntrophy, or the partnership of two species to metabolize a substrate despite an energetic barrier, is a dominant metabolic process in many environments where hydrocarbon biodegradation occurs. Understanding the syntrophic interactions that occur within microbial communities is important, since there is a possibility of uncovering novel microbial mechanisms and devise potential industrial applications. There is still much to be discovered about the specific interactions that occur within syntrophic partnerships, which is what this thesis project aimed to investigate. Metatranscriptomics was used to determine how gene expression changed when a bacterium maintained a syntrophic lifestyle, compared to an independent lifestyle in a pure culture. Co-cultures of the marine SRM Desulfatibacillum alkenivorans strain AK01 and either the methanogen Methanospirillum hungatei strain JF-1, or the marine methanogen Methanococcus maripaludis strain S2 were established. The differential gene expression analysis revealed that certain genes believed to be associated with syntrophic metabolic pathways and energy conservation were upregulated in both lactate-amended co-cultures. An additional contaminant organism within the cultures, Anaerovirgula multivorans, also may act as a syntroph based on gene expression and chemical activity data. Additionally, a co-occurrence network analysis was performed on eight mixed methanogenic hydrocarbon degrading consortia amended with different substrates. Multiple networks containing potential syntrophic organisms and methanogens were present, which could be used to establish future co-culture experiments.
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hydrocarbon biodegradation, syntrophy, methanogenesis, environmental microbiology, petroleum microbiology, metatranscriptomics, metagenomics
Citation
Goldsmith, C. A. (2023). Identification of genes and interactions involved in syntrophic biodegradation under methanogenic conditions (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.