REGULATION OF MALTOSE METABOLISM IN STATIONARY-PHASE CULTURES OF AN ASPOROGENOUS MUTANT OF BACILLUS-LICHENIFORMIS

An asporogenous strain of Bacillus licheniformis accumulated maltose b y an energy dependent transport mechanism during an extended stationar y phase. Maltose transport was sensitive to the effects of the uncoupl er tetrachlorosalicylanide (TCS), and was also inhibited by glucose. M altose stimulated synthesis of a p-nitrophenyl-alpha-D-glucoside-hydro lysing enzyme (pNPGase) in log phase and in stationary phase cells. In the presence of glucose this induction was inhibited. Glucose was use d preferentially to maltose in stationary phase cells. The uptake of m altose from the medium, and the synthesis of pNPGase, were immediately and completely inhibited in the presence of glucose. These results ar e consistent with a mechanism of inducer exclusion mediating the repre ssive effect of glucose upon pNPGase synthesis in stationary phase cel ls. Catabolite repression of a-amylase synthesis by glucose was also d emonstrated in late stationary phase mutant cells.