抄録
An additional study was done on the microbiological determination using Kloeckera apiculata which was described by Hoff-Jφrgensen and was modified by us (Vitamins 23,213,1961). Amount of thiamine in inoculum culture medium was changed to 0.2μg/2ml, instead of 1.0μg/2ml in previous report. An addition of vitamin-free yeast extract to the basal medium increased the cell growth. Thiamine-free yeast extract was prepared as follows. 50ml of 10% yeast extract is autoclaved at 120℃, 3Omin. after an addition of 0.25g of sodium sulfite, followed by removal of excess sulfite by hydrogen peroxide. Slant culture(about 10°) increased the sensitivity about two times as high as usual culture. The both cultures were useful for determination of 10-5Omμg of thiamine while shaking culture for 1-10mμg.
