L-SERINE PRODUCTION USING A RESTING CELL SYSTEM OF HYPHOMICROBIUM STRAINS

Twenty-six strains of methylotrophic hyphomicrobia were examined for their ability to produce L-serine from methanol and glycine in a resting cell reaction. L-Serine productivity of over 5 mg/ml was observed in 7 strains, and Hyphomicrobium sp. NCIB10099 was found to exhibit the highest productivity. Under optimized conditions using this bacterium, 45 Mg/Ml L-serine was produced from 100 mg/ml glycine and 88 mg/ml methanol in 3 d. The high L-serine degrading activity of the bacterium was entirely suppressed by adding an appropriate amount of CdCl2 (ca. 1 mM), resulting in an enhanced conversion ratio of glycine to L-serine (ca. 100% molar conversion).