Pantoea punctata sp. nov., Pantoea citrea sp. nov., and Pantoea terrea sp. nov. isolated from fruit and soil samples.

A total of 37 bacterial strains with the general characteristics of the family Enterobacteriaceae were isolated from fruit and soil samples in Japan as producers of 2,5-diketo-D-gluconic acid from D-glucose. These organisms were phenotypically most closely related to the genus Pantoea (F. Gavini, J. Mergaert, A. Beji, C. Mielearek, D. Izard, K. Kersters, and J. De Ley, Int. J. Syst. Bacteriol. 39:337-345, 1989) and were divided into three phenotypic groups. We selected nine representative strains from the three groups for an examination of DNA relatedness, as determined by the S1 nuclease method at 60 degrees C. Strain SHS 2003T (T = type strain) exhibited 30 to 41 and 28 to 33% DNA relatedness to the strains belonging to the strain SHS 2006T group (strains SHS 2004, SHS 2005, SHS 2006T, and SHS 2007) and to the strains belonging to the strain SHS 2008T group (strains SHS 2008T, SHS 2009, SHS 2010, and SHS 2011), respectively. Strain SHS 2006T exhibited 38 to 46% DNA relatedness to the strains belonging to the strain SHS 2008T group. The levels of DNA relatedness within the strain SHS 2006T group and within the strain SHS 2008T group were more than 85 and 71%, respectively. Strain SHS 2003T, SHS 2006T, and SHS 2008T DNAs exhibited less than 18% binding to Pantoea dispersa ATCC 14589T and Pantoea agglomerans ATCC 27155T DNAs.(ABSTRACT TRUNCATED AT 250 WORDS)

Production of 2-Keto-l-Gulonic Acid from d-Glucose by Two-Stage Fermentation.

A practical method for the production of calcium 2-keto-l-gulonate (an intermediate in the Reichstein synthesis of l-ascorbic acid) from d-glucose has been established by using a two-stage fermentation system. d-Glucose was first converted to calcium 2,5-diketo-d-gluconate by a mutant strain of Erwinia sp. in a medium containing d-glucose, corn steep liquor, (NH(4))(2)HPO(4), and CaCO(3). After a 26-h cultivation, 328.6 mg of calcium 2,5-diketo-d-gluconate per ml was obtained, with a 94.5% yield from d-glucose. This broth was used directly for the next conversion without removal of cells by treatment with sodium dodecyl sulfate. The stereospecific reduction of calcium 2,5-diketo-d-gluconate to calcium 2-keto-l-gulonate was performed with a mutant strain of Corynebacterium sp. When the cell growth reached a maximum (about 16 h) in a medium containing d-glucose, corn steep liquor, NaNO(3), KH(2)PO(4), and trace elements, NaNO(3) was added to the culture, and then the calcium 2,5-diketo-d-gluconate broth was fed over a period of about 50 h. Since the mutant strain requires a hydrogen donor for reduction, the calcium 2,5-diketo-d-gluconate broth was mixed with d-glucose before being fed. The results of four two-stage fermentations in 10-m conventional fermentors showed that an average of 106.3 mg of calcium 2-keto-l-gulonate per ml was obtained, with a 84.6% yield from d-glucose, the starting material of calcium 2,5-diketo-d-gluconate production. Calcium 2-keto-l-gulonate was stable in the broth. Neither 2-keto-d-gluconic acid nor 5-keto-d-gluconic acid was detected in the final broth.