Methanol Biosynthesis from Methane Using Methylosinus trichosporium OB3b Grown in Medium Containing High Copper Concentration

Abstract

Methanol production from methane in a batch reactor using whole cells of Methylosinus trichosporium OB3b grown in medium containing 50 μmol L^–1 copper was examined. Methanol productivity of the biocatalyst was 9.56 mmol g-dry cell^–1 h^–1, about 3-fold higher than that of the bacteria grown in medium containing 1.25 μmol L^–1 copper, indicating that methanol productivity of the methane bioconversion is improved by higher copper concentration in the growth medium. Methanol production almost ceased after 60-h reaction due to product inhibition. Therefore, repeated batch reaction was performed, in which the bacterial cells were collected after 24-h reaction and re-used in the next cycle. In the fourth cycle, 83 % of the methanol productivity was retained. About 856 mmol g-dry cell^–1 of methanol was obtained after 4 cycles, which was 3.7-fold higher than the methanol obtained in a single batch reaction for 96 h.