Abstract
For the purpose of investigating the non-cyano form of vitamin B12 occurring in nature, studies were conducted on the effect of various conditions of extraction and sterilization on the microbiological determinations of the vitamin using a bacterial preparation commercially available for supplementing the vitamin to the animal feed and the following results were obtained.
1. Differing from the active sludge and the methane fermentation bacterial fraction, a microbiologically active extract, equal in activity to the extract with hot aqueous cyanide, was obtained by simple water extraction at room temperature.
2. The non-cyano B12 obtained by water extraction at room temperature showed the activity equal to cyanocobalamin with the Lactobacillus leichmannii method described in U.S.P. XV, but an extremely low activity with the Ochromonas malhamensis method using the cyanide-free Ford medium.
3. Scarcely any decrease in activity was found with the Ochromonas method, when stabilizing agents such as ascorbic acid, thioglycolic acid or KCN is added or when the germfree extract obtained by filtration without heat sterilization was added aseptically. It suggests that the non-cyano B12 Per se in the sample is not poorly active to Ochromonas, but it is degraded in the course of heat sterilization with the Ford medium.
