Abstract

A thermotolerant methylotrophic Bacillus sp. (KISRI TM1A, NCIMB 40040), isolated from the Kuwaiti environment and belonging to the group II spore-forming bacilli, could not be correlated with any known Bacillus sp. It may, therefore, be a new species. It grew at temperatures from 37-degrees to 58-degrees-C, from pH 6.5 to 9.0 and on methanol up to 40 g l-1. It grew well in a chemostat. Its biomass yield coefficient was improved by about 30% by optimization of medium and growth conditions, reaching a maximum of 0.44 g g-1 at 45-degrees-C, pH 6.8 to 7.0, dilution rate 0.25 h-1 with methanol at 10 g l-1. Average crude protein and amino acid content were 84% and 60%, respectively, and maximum productivity attained under laboratory conditions was 5.06 g l-1h-1. It was concluded that this strain has good potential for use in single-cell protein production.