INFLUENCE OF THIAMIN ON GROWTH AND FAT FORMATION BY PENICILLIUM LILACINUM THOM.

Abstract

Penicillium lilacinum was grown on a high sugar–salts medium favorable for fat formation. Thiamin hydrochloride was added to 5-day-old cultures at three different concentrations, namely, 0.25, 2.5, and 5.0 mg/l. Sugar uptake, growth, and fat formation were followed after addition of vitamin for a period of 9 days. Sugar uptake was enhanced by the lowest and suppressed by the two higher vitamin concentrations. At higher concentrations, there was an early inhibition of dry weight increase, but by the end of the experiment, the weight of the high thiamin cultures equalled that of the controls. The effect of thiamin on fat formation was dependent on both the concentration and period of incubation. By the end of the incubation period, the low thiamin concentration had promoted fat formation, the high concentration had suppressed it, while the medium concentration was ineffective.