Continuous Hydrolysis of Milk Protein in a Membrane Reactor

Casein was hydrolyzed using Alcalase in a continuous stirred tank membrane reactor (CSTMR) using a hollow fiber ultrafiltration membrane. A design of experiments methodology was used to optimize the four performance variables: enzyme concentration, substrate concentration, permeate flux and reactor volume. High conversion (>90%) of the casein could be achieved after one hour at 50°C and pH 8. Reactor activity was most affected by the enzyme‐to‐substrate ratio. The stability of the reactor (i.e., decay of activity with time) was a function of enzyme leakage through the membrane, thermal inactivation and enzyme‐membrane interactions.