CONTROL OF DIACETYL PRECURSOR [ALPHA-ACETOLACTATE] FORMATION DURING ALCOHOL FERMENTATION WITH YEAST-CELLS IMMOBILIZED IN ALGINATE FIBERS WITH DOUBLE GEL LAYERS

During alcohol fermentation with yeast cells immobilized in single-lay ered gel beads, 0.94 mg/l of alpha-acetolactate, which is a diacetyl p recursor, was produced. However, by immobilizing the yeast cells in do uble-layered gel fibers, only 0.16 mg/l of alpha-acetolactate,was form ed. The free cells which leaked from the gel carrier made no significa nt contribution to the formation of alpha-acetolactate. The effectiven ess of double-layered gel fibers in reducing alpha-acetolactate format ion could be attributed to a more anaerobic condition inside the gel f ibers.