[Biosynthesis of corrinoids and other tetrapyrrole compounds by an acetogenic Clostridium]

Biosynthesis of corrinoids and other tetrapyrrole pigments by the pure culture of the acetogenic Clostridium 99 was studied. When growing on media containing glucose or methanol, the physiological and biochemical characteristics of Clostridium 99 are very close to those of C. thermoautotrophicum. Methanol was shown to stimulate the corrinoid accumulation with the yield increasing from 154 micrograms/g dry biomass (glucose medium) up to 2250 micrograms/g dry biomass (methanol medium). According to the paper chromatography the corrinoid accumulated in Clostridium 99 cells differed both from vitamin B12 and Factor III. A study on the composition of extracellular tetrapyrroles, accumulated when the culture grows on the medium containing glucose and delta-aminolevulinic acid, revealed that they are represented both by uroporphyrin III and sirohydrochlorine-like pigments. The latters differ by a number of properties from sirohydrochlorine (corrifirine-2) of propione acidic bacteria. These pigments appear to be involved as intermediants in biosynthesis of corrinoids and other tetrapyrroles.