Exploring Phenotypes of a Promising Industrial Methanotroph: An Experimental and Computational Study

Abstract

Methanotrophs are bacteria that directly convert methane under ambient conditions. In doing so, renewed research interest in their bioconversion capabilities have grown with the current abundance of methane and the global climate impact the gas has. Of the many different strains of methanotrophs, Methylomicrobium buryatense 5GB1 has gathered recent attention as a haloalkaliphilic strain that grows rapidly in medium that is naturally selective. Despite this peak in scientific study with methanotrophs and 5GB1, many unknowns remain. Specifically, this study strives to systematically investigate: (1) The effect of methane and oxygen concentrations on the growth rates and carbon distribution in small batch cultures; (2) Experimentally evaluate the effect of carbon distribution and growth on an “oxygen deprived” and “methane deprived” headspace with different dilution rates; (3) Conduct in silico analysis with experimental results to evaluate energy requirements and overall predictive performance with a constrained reduced genome scale metabolic model. From this work, creative, analytical methods and careful control procedures allowed for quantification of carbon distribution in under-pressurized vials or in continuous benchtop chemostats. With accurate experimental data, an initial phenotype characterization brings forth new insights on metabolic shifts within cells and raises fundamental biological questions during substrate deprived states. Overall, this study contributes to the necessary knowledge base to design processes for improved conversions with this promising biocatalyst.