Abstract

A fermentation system for the continuous ethanol production from sucrose and molasses using calcium alginate immobilized Saccharomyces cerevisiae strain HAU-1 has been optimised. Immobilization of active yeast cells (30%, w/v) was accomplished in 1.5% calcium alginate and these yeast-beads were employed for ethanol production in a vertical column reactor. High ethanol productivity was achieved with a medium containing 10%, w/v sucrose at a dilution rate of 0.20 h(-1). Alginate beads containing 30-50% yeast cell - mass resulted in high productivity 60.4 g l(-1) h(-1)). Sugarcane molasses containing 15% total sugars was fermented in column reactor to produce 6.0%, v/v ethanol in continuous system. These yields could be improved to 7.0% with overall 11% increase in fermentation - efficiency with the use of acid-clarified sugar cane molasses medium.