Efficient L-serine production from methanol and glycine by resting cells of Methylobacterium sp. strain MN43

Resting cells of methanol-utilizing microorganisms isolated from soils were examined for L-serine production under conditions in which L-serine-degradation was suppressed. Strain MN43, a facultative methylotrophic bacterium identified as a Methylobacterium sp., was selected for further studies. Under the optimal conditions, 65 mg/ml L-serine was produced by this bacterium from 50 mg/ml glycine and 104 mg/ml methanol in 5 days, with a molar conversion ratio from glycine to L-serine of 93%. This production is the highest so far reported for microbes producing L-serine.