Abstract
The biosynthesis of corrinoids by the two mutants of R. spheroides, PM-8 and PM-8 : bg 58,unable to grow photosynthetically, was studied. Corrinoids were extracted from the cells grown aerobically in the dark. Microbiological activities of the extracts from the strains PM-8 and PM-8 : bg 58 for Ochromonas malhamensis were 83% and 92% of those for Escherichia coli, respectively. Paper-ionophoretic and spectrophotometric investigation of the purified corrinoids showed that cobalamin was the major component of the corrinoids in the both strains. The yield of cobalamin coenzyme in PM-8 was 16μg per gram of dry cells. Thus, the formation of corrinoids in the two mutant strains seems to be similarto that in the wild strain of R. spheroides. The accumulation of coproporphyrin was stimulated by the addition of δ-aminolevulinic acid to the medium, while the corrinoid formation was not affected. The finding suggests that corrinoid formation might be restricted under the condition tested.
