Trehalose Production by a Strain of Micrococcus varians

Abstract

A bacterium isolated from soil was found to accumulate abundant trehalose in its medium. The bacterium was identified as a strain of Micrococcus varians from its taxonomical characteristics and was designated M. varians strain No. 39. Several other strains of Micrococcus and Deinococcus also accumulated extracellular trehalose but M. varians strain No. 39 produced the largest amount. Addition of manganese ions, and excess thiamine and nicotinamide, stimulated trehalose accumulation. Addition of 20 g/liter CSL led to the maximum conversion yield of trehalose in the production phase. Keeping the pH of the culture broth at 6.0 facilitated the maximum trehalose production rate. Cultivation of strain No. 39 at 32°C during the growth phase and 34°C during the production phase resulted in maximal trehalose production. Trehalose non-assimilating mutants (strain No. 7 and 9) derived from strain No. 39 accumulated about 15% more trehalose than the parent strain. Strain No. 7 produced 40 mg/ml trehalose from 100 mg/ml glucose under optimized conditions in a 5-liter jar fermentor.