IMMOBILIZATION OF SACCHAROMYCES-CEREVISIAE FOR ETHANOL FERMENTATION ON GAMMA-ALUMINA PARTICLES USING A SPRAY-DRYER

Saccharomyces cerevisiae was immobilized on gamma-alumina particles with binder polymer by a spray-drying process, Batch fermentations of sucrose to ethanol were performed using the immobilized cells. The optimum pH was 4, and this helped to minimize microbial contamination and facilitate electrostatic attraction between the gamma-alumina particles and the yeast cells. Addition of yeast extract resulted in high ethanol conversion. The reasons for differences between cellulose acetate phthalate (CAP) and styrene-maleic acid co-polymer (SMC) as binders on ethanol conversion were not apparent. The release of binder with the SMC from the gamma-alumina was less than that from the CAP. Presoaking of gamma-alumina particles in resin for binder solution before the immobilization using a spray-dryer was effective in achieving high ethanol conversion.