INDUCTION OF ALPHA-AMYLASE OF BACILLUS STEAROTHERMOPHILUS BY MALTODEXTRINS.

Welker, N. E. (Western Reserve University, Cleveland, Ohio) and L. Leon Campbell. Induction of alpha-amylase of Bacillus stearothermophilus by maltodextrins. J. Bacteriol. 86:687-691. 1963.-Technical-grade maltose contained 3.5% glucose, 0.5% maltotriose, and 2.5% of the higher molecular weight maltodextrins. The first five homologues (maltose being the first in the series) of the maltodextrin series were isolated and purified. Each member of the series was found to be chromatographically pure. The physical and chemical properties were determined. It was shown that the contaminating maltodextrins found in technical grade maltose were linear (1-4 linked) polymers of glucose, ranging from maltotriose to maltohexaose. The addition of maltose, maltotriose, maltohexaose, maltopentaose, and maltotetraose (all at 10(-4)m) to cultures growing in a chemically defined medium resulted in a stimulation in the differential rate of alpha-amylase synthesis by 1.2, 1.6, 1.9, 2.3, and 3.0 times that of the sucrose control, while glucose had no effect. The induction data indicate that Bacillus stearothermophilus 1503-4 is a partial constitutive strain with respect to alpha-amylase synthesis.