Starch hydrolysis kinetics of Bacillus licheniformis alpha-amylase

The reaction kinetics for thermostable Bacillus licheniformis α‐amylase was determined under two sets of conditions: an initial rate study over a range of low starch concentrations (1–8%, w/w) in a batch reactor, and a continuous rate study at a high starch concentration of 40% during which a twin‐screw extruder was used as a bioreactor for the first 600 s and the reaction was continued to equilibrium in a batch reactor. The Michaelis–Menten model was found to be sufficient for describing the kinetics at low starch concentrations; however, a modified first‐order model was required at high concentration. There was no evidence of substrate inhibition at the high starch concentration. The rate of product formation, calculated in terms of dextrose equivalent (DE) values, was found to be proportional to the square root of the rate of starch consumption.