A modified form of a vitamin B12 compound extracted from whey fermented by Lactobacillus helveticus

The content of vitamin B12 in whey was reduced considerably during lactic acid fermentation, which was analogous to the lactic acid fermentation of milk. This apparent B12 decrease in whey was caused by B12 compounds that were unextractable by conventional extraction with potassium cyanide but that could be extracted by sonication and treatment by proteases such as pepsin and papain. Forms of the extracted B12 compounds were examined by bioautographies with Escherichia coli 215, coupled with cellulose acetate membrane electrophoresis or HPLC, and were identified as adenosylcobalamin, cyanocobalamin, and hydoroxocobalamin. A considerable amount of unidentified B12 was also detected, and this unidentified B12 compound seems to be the principal B12 compound that was unextractable from the cells.