Microbial growth on a medium containing methanol and bicarbonate under anaerobic conditions in the light.

Abstract

Enrichment cultures in a medium containing 0.1% methanol and 0.1% bicarbonate at pH 7.0 under anaerobic conditions in the light became mainly green in color. Forty-four enrichment cultures, which showed abundant growth, were obtained from 46 different sources and found to contain cells of methanol-utilizing bacteria and green algae as predominant members. From these enrichment cultures, two strains of bacteria and two strains of algae were isolated. The microorganisms isolated were designated as bacterium No. 7, bacterium No. 8, Chlorella sp. A-l and Chlorella sp. B-l, respectively. Stable mixed cultures were easily formed by mixing the isolated cultures of bacteria and algae. Both methanol and bicarbonate were necessary for the growth of the mixed cultures under anaerobic-light conditions. Growth behavior of the mixed cultures was examined on a medium containing 0.1 % methanol and 0.1% bicarbonate at 30°C in the light (about 60001x). The maximum specific growth rate for the cultures, μmax, was 0.092 hr-1 (doubling time, 7.5 hr). The maximum cell yield was 0.87 g dry-cell weight per g of methanol used. The protein content of the biomass was 65%.