Ikuo Kojima

Thin-layer chromatographic analysis of carbapenem antibiotics in fermentation broths

Abstract A one-dimensional silica gel thin-layer chromatographic method has been devised for qualitative and quantitative analysis of carbapenem antibiotics in fermentation broths. The antibiotics were extracted from the broth filtrate with a solvent mixture of 1-butanol and chloroform (1:1) and developed on a silica gel thin-layer plate with a mobile phase of acetonitrile—0.75% acetic acid (9:2). Carbapenem compounds on the thin-layer plate were visualized as reddish pink spots with the Ehrlich reagent and quantitated by densitometry.

Structures of OA-6129A, B1, B2 and C, new carbapenem antibiotics

Abstract The structures of carbapenems OA-6129A, B 1 , B 2 and C were determined by spectroscopy and chemical transformation.

Preferential production of a carbapenem antibiotic, PS-5 by dissolved oxygen controlled fermentation

Abstract As Streptomyces fulvoviridis A933-17M9 usually produces several carbapenem analogs including PS-5, the submerged fermentation conditions were optimized for preferential production of PS-5. The scale of PS-5 fermentation was expanded stepwise from a 2.5- l mini-jar fermentor to a 1500- l pilot-scale fermentor. For production of PS-5 as a major product among related carbapenem analogs, the concentration of dissolved oxygen during fermentation was controlled at levels where microbial conversion of PS-5 to epithienamycins A and C and further to MM17880 was largely prevented without deleterious influences on the carbapenem-biosynthesizing activity of mycelia.