Synergistic Interaction of Methanotrophs and Methylotrophs in Regulating Methane Emission

The atmospheric methane concentration is increasing rapidly at the rate of around 10 ppb/year. A concerted effort is required to reduce methane emission. Methanotrophs possess methane monooxygenase enzyme system and can consume a major portion of the methane produced in the environment. These microbes play a major role in the single-carbon-driven microbial food web. Microbial interaction is an important component of microbial ecology studies, and its role in community functioning and various biogeochemical cycles still remains unclear. A synergistic interaction occurs between the methanotrophs and non-methane-utilizing methylotrophs (NUM) in the natural ecosystem. The intermediates produced by the methanotrophs can be used as a carbon source by the NUM and support its existence. On the other hand, NUM consumes toxic intermediates like methanol and formaldehyde of the methanotrophs and prolongs their growth. The consumption of the intermediates (methanol, formaldehyde and formate) of the methane utilization pathway by methylotrophs as a result of cross-feeding enhances the methane utilization rate of that ecosystem. Co-inoculation of methanotrophs and NUM in the natural habitat particularly paddy ecosystem can aid in the reduction of net methane emission. This chapter highlights the role of microbial interactions, particularly between methanotrophs and methylotrophs, that can be harnessed to mitigate methane emission from the methane-rich environment.