Thermostable alpha-amylase production by immobilized Bacillus licheniformis cells in agar gel and on acrylonitrile/acrylamide membranes.

Immobilized cells of Bacillus licheniformis 44MB82-G were used for the production of thermostable alpha-amylase. The immobilization was carried out by entrapment in agar gel or by binding to formaldehyde-activated acrylonitrile/acrylamide membranes. The alpha-amylase production after 144 h of cultivation of membrane immobilized cells was 40% higher in comparison with the free cells. The respective value for the agar-entrapped cells was 22%. Similar trends were observed in the repeated batch fermentations performed with the immobilized cells. The scanning electron micrographs (SEM) of the immobilized cells gave additional information about their binding to the respective carriers.