Biosensing systems for the detection and quantification of methane gas.

Climate change due to the continuous increase in the release of green-house gasses associated with anthropogenic activity has made a significant impact on the sustainability of life on our planet. Methane (CH) is a green-house gas whose concentrations in the atmosphere are on the rise. CH measurement is important for both the environment and the safety at the industrial and household level. Methanotrophs are distinguished for their unique characteristic of using CH as the sole source of carbon and energy, due to the presence of the methane monooxygenases that oxidize CH under ambient temperature conditions. This has attracted interest in the use of methanotrophs in biotechnological applications as well as in the development of biosensing systems for CH quantification and monitoring. Biosensing systems using methanotrophs rely on the use of whole microbial cells that oxidize CH in presence of O, so that the CH concentration is determined in an indirect manner by measuring the decrease of O level in the system. Although several biological properties of methanotrophic microorganisms still need to be characterized, different studies have demonstrated the feasibility of the use of methanotrophs in CH measurement. This review summarizes the contributions in methane biosensing systems and presents a prospective of the valid use of methanotrophs in this field. KEY POINTS: • Methanotroph environmental relevance in methane oxidation • Methanotroph biotechnological application in the field of biosensing • Methane monooxygenase as a feasible biorecognition element in biosensors.