Production of D-glucose dehydrogenase for the determination of D-glucose

The optimum conditions for D-glucose dehydrogenase production from Bacillus thuringiensis M15 were investigated in flask cultures. Various concentrations of carbon and nitrogen sources including the culture conditions were studied for the enzyme production. The highest enzyme yield was obtained from 100 ml of cultivation medium containing (w/v) 0.12% trehalose, 0.25% ammonium chloride, 0.1% KH2PO4, 0.1% K2HPO4, 0.01% MgSO(4)(.)7H(2)O and 0.02% yeast extract, pH 6.5. The suitable culture condition at 30 degreesC was shaking speed at 100 rev min(-1) for 2 days. The highest enzyme activity and specific activity in flask culture were 3 mU ml(-1) and 6 mU mg(-1), respectively. At the final optimization step, the enzyme total unit was higher than the beginning step about 4 times. The maximum enzyme activity in a jar fermentor which obtained from 21 h cultivation was 1.27 mU ml(-1).