UC San Diego

Methane levels have rapidly increased in concentration in the atmosphere due to anthropogenic inputs making it a crucial abatement target against global climate change. The aerobic methanotrophs are bacteria capable of growth solely on methane as substrate and are genetically tractable and amenable to large scale fermentation making them ideal model system for the engineering of C1- biocatalysts. In this dissertation I examine the effects of trace minerals and substrate on the cell performance of Methylotuvimicrobium alcaliphilum 20ZR by contextualizing multi-omics with structural characterization through electron microscopy. This reveals the development of the intracytoplasmic membrane network within the cell which is affected by metals and leads to the increased gas consumption. Occupying the cell volume with membranes leads to an overflow metabolic state in conditions with sufficient substrate and oxygen in which fermentation products such as formate are excreted.. The nature of structural features revealed by microscopy is explored to determine the genetic elements for expression and transport of the surface layer protein. Genes responsible for the large and small proteins of the surface layer protein matrix are identified and a Type 1 Secretion System is explored as the potential mechanism of export for this cell surface feature. Concluding with an exploration of a novel methane chemotactic phenotype, which was identified by structural modelling and confirmed through a methane-based chemotaxis assay. This work demonstrates the importance of tying systems-level data such as proteomics with structural information gathered by electron microscopy to explain and explore phenotypes of performance such as growth rate and substrate consumption to cell biology of a model organism used as a methane-based biotechnology strain.