Glucose uptake in Clostridium beijerinckii NCIMB 8052 and the solvent-hyperproducing mutant BA101

Glucose uptake and accumulation by Clostridium beijerinckii BA101, a butano l hyperproducing mutant, were examined during various stages of growth. Glu cose uptake in C. beijerinckii BA101 was repressed 20% by 2-deoxyglucose an d 25% by mannose, while glucose uptake in C. beijerinckii 8052 was represse d 52 and 28% by these sugars, respectively. We confirmed the presence of a phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) associa ted with cell extracts of C. beijerinckii BA101 by glucose phosphorylation by PEP. The PTS activity associated with C. beijerinckii BA101 was 50% of t hat observed for C. beijerinckii 8052. C. beijerinckii BA101 also demonstra ted lower PTS activity for fructose and glucitol. Glucose phosphorylation b y cell extracts derived from both C. beijerinckii BA101 and 8052 was also d ependent on the presence of ATP, a finding consistent with the presence of glucokinase activity in C. beijerinckii extracts. ATP-dependent glucose pho sphorylation was predominant during the solventogenic stage, when PEP-depen dent glucose phosphorylation was dramatically repressed. A nearly twofold-g reater ATP-dependent phosphorylation rate was observed for solventogenic st age C. beijerinckii BA101 than for solventogenic stage C. beijerinckii 8052 . These results suggest that C. beijerinckii BA101 is defective in PTS acti vity and that C. beijerinckii BA101 compensates for this defect with enhanc ed glucokinase activity, resulting in an ability to transport and utilize g lucose during the solventogenic stage.