Studies on Kinetics of Alkaline Protease Production of by Bacillus licheniformis

Abstract

Proteases are the most important enzymes produced by Bacillus licheniformis. The protease producer strain Bacillus licheniformis GCU-12 was isolated from the soil. Fermentation medium containing Glucose 5.0; Peptone 7.5; NaCl 5.0; MgSO₄.7H₂O 5.0; FeSO₄.7 H₂O 0.1; was used for the production. The production was investigated in stirred fermenter as well as shake flasks. In stirred fermenter the culture produced 56 U/cm³during 24 h fermentation At 9.0 and 40^oC. The kinetic and mass balance studies revealed that the growth rate was 0.25 h^-1 during first 12 hrs of fermentation in the stirred fermenter and 0.183 h^-1 for first 18 hrs of fermentation in shake flasks. The value of number of generations and its doubling time in the fermenter were 4.33 and 2.8 h whereas the number of generations and the doubling time for shake flasks were 4.8 and 3.79 h. The substrate uptake rate of biomass was 2.9 g/dm³/hour in fermenter and 1.8 g/dm³/hour for shake flasks while specific substrate uptake rate was maintained 0.2 g substrate-g^-1 biomass-h^-1 during exponential phases both in the shake flask and the stirred fermenter.