A number of bacterial strains from type culture collections and natural sources were examined in their metabolic characteristics toward sorbitol and L-sorbose.Paper chromatographic analyses of sorbitol and L-sorbose metabolites obtained from the cultures of various bacteria revealed that the organisms producing 2-keto-L-gulonic acid from sorbitol were merely found in the genera Acetobacter, Gluconobacter and Pseudomonas, whereas those producing the acid from L-sorbose were distributed in the twelve genera of bacteria: Acetobacter, Alcaligenes, Aerobacter, Acotobacter, Bacillus, Escherichia, Gluconobacter, Klebsiella, Micrococcus, Pseudomonas, Serratia and Xanthomonas.G. melanogenus, which was characterized by excellent production of 2-keto-L-gu Ionic acid from sorbitol, also formed several other sugars and sugar acids as the sorbitol metabolites. These compounds were identified to be D-fructose, L-sorbose, D-mannonic acid, L-idonic acid, 2-keto-D-gluconic acid and 5-keto-D-mannonie acid, respectively, by means of two-dimensional paper chromatography.Bacteria producing 2-keto-L-gulonic acid from sorbitol were usually isolated from fruits but not from soil.

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The effect of biotin and oleic acid on the cellular fatty acid contents, and the relation between the cellular fatty acid contents and the productivity of L-glutamic acid were investigated using Brevibacterium thiogenitalis No. 653 and its oleic acid-requiring mutant, D-248. While the synthesis of palmitic acid in D-248 was stimulated by biotin and competi tively reversed by oleic acid added to the culture medium, the level of cellular oleic acid was scarcely affected by biotin but regulated by oleic acid in the medium. For the productivity of L-glutamic acid, the most important factor was the level of cellular oleic acid, and the effect of cellular palmitic acid was considerably weak. This relation was subjected to a figuration and able to be expressed on the whole as one ex ponential-like curve. An amount of over 70 per cent of cellular fatty acids was distributed in the phospholipid fraction and its fatty acid composition was almost the same as that of whole cells.

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