Integrated bioprocess for carbon dioxide sequestration and methanol production.

Carbon dioxide (CO2) poses a significant threat, contributing to global warming and climate change. This study focused on isolating efficient CO2-reducing methanogens and methanotrophs for converting methane into methanol. Samples from diverse regions in India were collected and processed, yielding 82 methanogenic and 48 methylotrophic isolates. Methanogenic isolate M11 produced a higher amount of methane, reaching 2.9 mol L-1 on the sixth day of incubation at 35 °C, pH 7.0, and CO2:H2 (80:20) as feeding rates. Under optimized conditions, isolate M11 effectively converted 8.3 mol CO2 to 7.9 mol methane in 24 h. Methylotrophic isolate M31 demonstrated significant soluble methane monooxygenase activity (450 nmol/ml) and produced 0.4 mol methanol in 24 h. 16S rRNA analysis identified Methanobacterium sp. and Methyloceanibacter sp. among the isolates, elucidating their taxonomic diversity. This study offers valuable insights into methanogens' potential in CO2 sequestration and methane conversion to methanol through methanotrophism, a promising sustainable biofuel production.