Methanotrophs: The Natural Way to Tackle Greenhouse Effect

Abstract

Methane is considered as an important greenhouse gas which produced from a wide range of anthropogenic and natural sources. It plays a key role in global warming. Capturing and disposal of methane is technically both costly and problematic. A low-cost alternate to the conventional methods is the microbial oxidation of methane. Methanotrophs are the type of bacteria that aerobically oxidize methane as a source of energy through their key enzyme, monooxygenase (MMO), especially the soluble MMO, it is noteworthy in its broad substrate specificity. This exceptional capability, i.e., catalyzing reactions of environmental importance, has owned methanotrophs attention from applied microbiologists and biotechnologist. From about 30 years, it is observed that copper (Cu) is playing an important role in the physiology and activity of methanotrophs, but the discovery of how Cu collect by these cells, more importantly what is the role Cu playing in CH4 oxidation by the particulate CH4 monooxygenase and how Cu affects the ability of methanotrophs to oxidize different substrates has been made. In this review we summarize the morphology, phylogeny, ecology, and possible applications of methanotrophs to address the global as well as regional issues, along with the role of gene expression regulation by Cu and how it affects the cell activity of methane-oxidizing bacteria. Our focus was on two main aspects of potential value and application of methanotrophs in environmental bioremediation, namely physiology along with working of methanotrophs and methane removal from atmosphere.