Abstract:α-Acetolactate decarboxylase was concentrated from Bacillus subtilis with polyethersulfone(PES) ultrafiltration membrane.The effects of temperature and pH value on membrane flux were investigated to determine the recovery conditions of chemical and enzymatic cleaning of ultrafiltration membrane. The result show that membrane flux is affected strongly by pH value of enzyme solution. After 10fold concentration, the permeate flux at pH of 5.1 is only 20.3% of that at pH of 7.1.The recovery of αacetolactate decarboxylase can reach 89.6% at the optimum ultrafiltration conditions for pressure of 0.1 MPa, temperature of 35 ℃, and pH value of 7.1. During enzymatic cleaning, the high neutral protease activity of 1.25×104 U·L-1 can result in membrane refouling. The best cleaning effect can be achieved by combining neutral protease of 1.25×104 U·L-1 and sodium hypochlorite of 1% with flux recovery rate of 97.0%.