CARBOHYDRATE UTILIZATION IN LACTOBACILLUS-SAKE

The ability of Lactobacillus sake to use various carbon sources was in vestigated, For this purpose we developed a chemically defined medium allowing growth of L. sake and some related lactobacilli, This medium was used to determine growth rates on various carbohydrates and some n utritional requirements of L. sake, Mutants resistant to 2-deoxy-D-glu cose (a nonmetabolizable glucose analog) were isolated, One mutant una ble to grow on mannose and one mutant deficient in growth on mannose, fructose, and sucrose were studied by determining growth characteristi cs and carbohydrate uptake and phosphorylation rates, We show here tha t sucrose, fructose, mannose, N-acetylglucosamine, and glucose are tra nsported and phosphorylated by the phosphoenolpyruvate:carbohydrate ph osphotransferase system (PTS). The PTS permease specific for mannose, enzyme IIMan, was shown to be responsible for mannose, glucose, and N- acetylglucosamine transport, A second, non-PTS system, which was respo nsible for glucose transport, was demonstrated, Subsequent glucose met abolism involved an ATP-dependent phosphorylation, Ribose and gluconat e were transported by PTS-independent permeases.