Abstract
Some fundamental investigations were made on the vitamin B_<12> fermentation with Streptomyces olivaceus. Vitamin B_<12> formation was completed after 3 days, after which the vitamin began to liberate and substantially all was liberated after 7 days. Thirty ml. per flask in rotary shaker or 15 ml. per tube in test tube shaker, each corresponding to oxygen absorption rate 0.7,was found desirable for normal fermentation. No improvement was made with increased sugar concentration or feeding. Three times as much vitamin B_<12> was formed by the addition of from 1 to 200 ppm of CoCl_2・6aq., but 200 or 500 ppm delayed initial growth, and 500 ppm lowered vitamin B_<12> formation. No appreciable effect was observed by inoculum size. The original culture was found to be fairly uniform with respect to vitamin B_<12> productivity.
