Induction of Lipomyces starkeyi Dextranase

Lipomyces starkeyi ATCC 20825 is a derepressed mutant derived from L. starkeyi ATCC 12659. It requires the presence of an inducer before it produces dextranase. This study was undertaken to determine the most efficient, commercially feasible method for inducing this Enzyme. The following compounds induced dextranase synthesis: 1-O-beta-methyl-glucopyranoside, 1-O-alpha-methyl-glucopyranoside, dextran, isomaltopentose, isomaltotetraose, isomaltotriose, and isomaltose. 1-O-beta-Methyl-glucopyranoside was found to be a gratuitous inducer. Early in the growth phase, cells produced higher specific levels of Enzyme than they did in late log phase. The length of exposure of the yeast cells to the inducer also affected the amount of dextranase produced. The maximum amount of Enzyme was produced after 12 h of exposure to the inducer. The saturation concentration was the same for all inducers tested, i.e., approximately 1 mg of inducer for every 2 x 10 cells.