Process engineering strategy for improved methanol production in Methylosinus trichosporium through enhanced mass transfer and solubility of methane and carbon dioxide.

Methanol was produced in a two-stage integrated process using Methylosinus trichosporium NCIMB 11131. The first stage involved sequestration of methane to produce methanotrophic biomass, which was utilized as biocatalyst in the second stage to convert CO into methanol. A combinatorial process engineering approach of design of micro-sparger, engagement of draft tube, addition of mass transfer vector and elevation of reactor operating pressure was employed to enhance production of biomass and methanol. Maximum biomass titer of 7.68 g/L and productivity of 1.46 g/L d were achieved in an airlift reactor equipped with a micro-sparger of 5 µm pore size, in the presence of draft tube and 10 % v/v silicone oil, as mass transfer vector. Maximum methane fixation rate was estimated to be 0.80 g/L d. Maximum methanol titer of 1.98 g/L was achieved under an elevated operating pressure of 4 bar in a high-pressure stirred tank reactor.