Production of methanol from biogas using methanotrophs for the application in a microbial fuel cell

Abstract

Abstract Methane is available in abundance as natural and renewable gas. Methane-rich biogas has low power density so cannot be considered as a good substrate for the microbial fuel cell. The power density of methane-rich biogas can be increased by its conversion to methanol. Two-step strategy has been followed for the production of methanol from methane-rich biogas and its utilization in a microbial fuel cell. Methanol production using methanotrophs is an attractive way for the valorisation of waste-derived biogas. Besides this, methanotrophs have been used in converting the methane-rich biogas into a variety of bioproducts which include single cell protein, polyhydroxyalkanoate bioplastics, biodiesel, extracellular polysaccharides, propylene oxide, and human health supplements. This paper focusses on the biological conversion of methanol in which solid-state anaerobic digestate can be used for the isolation of methanotrophic bacterium. A fresh isolate possesses the characteristics which resembled to constrained methanotrophs from the methylocaldum genus. This freshly new isolated methanotroph evolved on purified methane or biogas and successful production of methanol is accomplished from the biogas. This study also deals with the effect of formate and various inhibitors of methanol dehydrogenase for the biological conversion of methanol and where the formate act as an electron donor. But isolate produced methanol without any electron donor with the help of phosphate. Moreover, isolate also produced methanol without methanol dehydrogenase inhibitor by the use of formate. The maximum quantity of methanol consists of an optimum quantity of formate and phosphate as a growth medium. This study reveals an efficient conversion of methanol from biogas using solid-state anaerobic digestate. The produced methanol will not go for the purification process and can be used directly in a microbial fuel cell for the power generation purpose.