Ryuichiro Tsugawa

Fermentation of n-Paraffins by Yeast: Part III. α-Ketoglutarate Productivity of Various Yeast

α-Ketoglutarate productivity from n-paraffins of 141 strains of identified yeasts was studied. Among the strains tested, only strains of Candida lipolytica exclusively showed a high ability to produce α-ketoglutarale.It was also observed that these strains of Candida lipolytica required thiamine for their growth and that exegenous thiamine stimulated the activity of α-ketoglutarate dehydrogenase of Candida lipolytica AJ 5004.From these results, relationship between thiamine requirement and α-ketoglutarate productivity of Candida lipolytica was discussed.α-Ketoglutarate fermentation by representative strains of Candida lipolytica was also carried out.

Fermentation of n -Paraffins by Yeast:Part II. α-Ketoglutarate Productivity of Candida lipolytica in Various Culture Media

Nutritional requirement of Candida lipolytica AJ 5004 and its productivity of α-ketoglutarate were further studied.It became clear that this yeast required only thiamine as grown factor, and even if the yeast was cultured in chemically defined medium containing adequate amount of thiamine, it was able to produce as high yield of α-ketoglutarate as in the medium containing 0.02% of corn steep liquor.It was also shown that the rate of convertion of n-paraffin to α-ketoglutarate gradually increased as the concentration of n-paraffins was decreased or as the incubation time was prolonged. A very high rate of conversion, 71%, was obtained after prolonged culture, for 5 days, with a culture medium containing 8% of n-paraffins.The productivity of α-ketoglutarate from C9- to C20-alkanes by the yeast was maximum in the range from C15 to C19, especially from C17 to C19.

Production of l-Glutamic Acid from dl-Hydantoin-5-propionic Acid by Microoganisms: Part I. Screening of l-Glutamic Acid-Producing Microorganisms and Some Optimal Conditions for Production of l-Glutamic Acid

Screening tests for obtaining microorganisms which can produce l-glutamic acid from hydantoin-5-propionic acid were carried out. Many strains of microorganism were found to possess this ability. It was newly found that the glutamic acid produced by these strains was exclusively l-form regardless of the stereochemical configuration of the substrate used.Among the selected strains Bacillus brevis ATCC 8185 showed the highest ability to produce l-glutamic acid.Some investigations for obtaining optimal conditions for producing l-glutamic acid using washed cells of Bacillus brevis ATCC 8185 were carried out. Under the adequate conditions using the reaction mixture containing 1.0% of dl-hydantoin-5-propionic acid, washed cells of this strain converted 90% of the dl-acid to l-glutamic acid.An assumptive pathway of producing L-glutamic acid from D-hydantoin-5-propionic acid was also discussed.