Ryoji Kodaira

Mechanism of adenosine production by xanthine-requiring mutants derived from a Bacillus strain

Abstract The xanthine-requiring mutants defective in adenine deaminase (adenase) derived from a Bacillus strain accumulate much adenosine. The mechanism of adenosine production was investigated. Limitation of the guanine-related substances in the fermentation medium facilitated the adenosine accumulation, but the excess of those suppressed it. Metabolic regulation of the purine nucleotide biosynthesis was supposed to be released from both feedback inhibition and repression by limiting the concentration of guanine-related substances in the cells caused by xanthine-requirement. Deficiency in the deaminase activities of adenine, adenosine and AMP and the weak adenosine phosphorylase activity contributed to adenosine accumulation. No apparent changes were observed in the adenylosuccinate synthetase activity and the dephosphorylation activity of AMP compared with the wild strain.

Accumulation of Nucleic Acid-related Substances by Microorganisms: Part II. Production of Adenosine by Mutants Derived from Bacillus sp.

The induction of adenosine-producing mutants from an inosine-producing mutant previously derived from a Bacillus strain was attempted, and it was found out that the xanthine-requiring mutants lacking of adenase produce a large amount of adenosine.The outline of the processes for the derivation of these mutants was described. Main product of these mutants was adenosine, and the culture broth contained a little amount of adenine as a by-product.The culture conditions optimal for the production of adenosine were investigated, and the yield of adenosine in the culture broth was more than 16 mg/ml.

Studies on L-Glutamic Acid Fermentation by Microbacterium ammoniaphilum :Part II. Biotin-Effect on L-Glutamic Acid Production

The present investigation is concerned with the effects of biotin and glucose on glutamic acid fermenation by Microbacterium ammoniaphilum. Both optimal amounts of biotin necessary for maximum growth and maximum accumulation of glutamic acid were determined under the conditoin of various concentration of glucose. As the glucose concentratin was increased, the amounts of biotin required for maximum growth also increased proportionally to the glucose concentrations. The optimal amounts of biotin for maximum accumulation of glutamic acid were smaller than those for maximum growth of cells at any glucose concentration. It is suggested that the process of glutamic acid accumulation is inevitably associated with the process of cell multiplication by both experiments of successive culture of cells grown under the dose of biotin sufficient and deficient for maximum growth.