ALPHA-AMYLASE PRODUCTION BY BACILLUS-AMYLOLIQUEFACIENS IN A MEMBRANE RECYCLE BIOREACTOR

A strain of Bacillus amyloliquefaciens was cultivated in a membrane re cycle bioreactor for the production of an extracellular alpha-amylase. Continuous cultivations of B. amyloliquefaciens in the recycle fermen ter led to higher cell mass and volumetric productivities than the one s obtained in batch or chemostat cultivations; the alpha-amylase activ ities were lower than in the batch mode but significantly higher than in the chemostat mode. The operation of the membrane recycle bioreacto r was sometimes disturbed by high broth viscosity leading to a stronge r fouling of the membrane.