Abstract
Forty-two bacterial strains that produce calcium 2, 5-diketo-D-gluconate from 30% (w/v) D-glucose with yields of more than 70 mol% were isolated from various soil and fruit samples. They were small rod-shaped, gram-negative, non-spore-forming and facultatively anaerobic bacteria, and could be classified taxonomically into three groups. Representative strains (SHS 2003, ATCC 31623; SHS 2006, ATCC 31626; SHS 2008, ATCC 31628) of the latter were identified as members of the genus Erwinia. The DNA base ratios of these strains ranged from 46.3 to 48.7 mol% guanine plus cytosine.
The results of experiments using whole cells and cell extracts of these three strains suggested that D-glucose is oxidized to 2, 5-diketo-D-gluconate via D-gluconate and 2-keto-D-gluconate. No 5-keto-D-gluconate was detected in the culture broth throughout their cultivation. Most activities of enzyme(s) responsible for the oxidation of D-glucose to 2, 5-diketo-D-gluconate were found in the particulate fractions of these strains.
