α-Amylase production by immobilized whole cells of Bacillus subtilis

Summary

Whole cells of Bacillus subtilis were immobilized in polyacrylamide gel prepared from 5% total acrylamide (85% acrylamide and 15% N,N′-methylenebisacrylamide). Production of α-amylase by the immobilized whole cells was attempted in a batch system. α-Amylase produced by the immobilized whole cells was about three times larger than that produced by washed cells at optimum conditions. The reusability of the immobilized whole cells and washed cells was examined. The activity of α-amylase production by washed cells decreased with increasing use cycles. On the other hand, the activity of the immobilized cells increased gradually, and it reched a steady state after seven cycles. α-Amylase was produced from a simple reaction medium containing 1% meat extract and 0.05% yeast extract by the immobilized whole cells. The rate of α-amylase production by the immobilized whole cells was the same as in submerged cultivation using starch bouillon medium. Growth of B. subtilis in polyacrylamide gel was observed by electron microscopy.