PRODUCTION OF DEXTRANSUCRASE BY LEUCONOSTOC-MESENTEROIDES IMMOBILIZED IN CALCIUM-ALGINATE BEADS .1. BATCH AND FED-BATCH FERMENTATIONS

In batch fermentation Leuconostoc mesenteroides immobilized in calcium alginate beads produced a total dextransucrase activity equal to about 93% of that by free, suspended bacterial cells under comparable conditions in a bubble column reactor. Continuous sucrose feeding (5 g/L h) to the immobilized‐cell culture in the airlift bioreactor increased production of enzymatic activity by about 107% compared with ordinary batch operation of this reactor. About 14% of the enzymatic activity produced by the immobilized cells appears as soluble activity in the cell‐free broth compared with about 40% in case of free cells. In an airlift bioreactor, both the soluble and the intact (sorbed and entrapped) enzymatic activity produced by the immobilized bacterial cells was about 34% greater under automatic pH control, compared to that produced in a bubble column reactor with only manual pH control. During formation of dextran by intact enzyme within cells and beads, declines are observed in apparent enzymatic activity. Copyright © 1990 John Wiley & Sons, Inc.