Abstract
Further experiments were conducted for higher vitamin B_<12> production by the improvements of culture media. Supplementations to media with various compounds including o-phenylenediamine, proline, cyanides, chlorophyllin and plant hormones failed to induce a stimulation of vitamin B_<12> production. Maltose which had been shown previously to be the most potent carbon source when used singly was found less active than lactose when used in combination with glucose. Addition of SVP more than 6% resulted in a reduced the vitamin production. It was found that the enrichement of media with lactose induced an abundant mycelial growth, but the abundance did not necessarily mean an increased vitamin B_<12> production. The highest yield obtained was 8.5μg/ml after 12 days fermentation.
