Immobilization of Saccharomyces Cerevisae cells on water hyacinth stem pieces and application to repeated batch fermentation for ethanol production

Abstract

Water hyacinth (Eichhorniacrassipe) stem pieces were used as supports for Saccharomyces cerevisiae immobilization. The response surface methodology was implemented to maximize the cell immobilization yield. This methodology optimized the amount of water hyancinth pieces added to yeast suspension and the initial cell concentration in yeast suspension prior to the immobilization. The immobilized yeast on water hyacinth stem pieces was then applied to ethanol fermentation with 12 repeated batches. The ethanol production rate of the immobilized yeast was significantly higher than that of the free yeast. In addition, gradual increase in the metabolic activity of the immobilized cell system was also observed during the 12 fermentation batches. The ethanol production rate of the immobilized yeast in the twelfth batch culture was increased by 29.8% compared to that in the first batch culture.

Keywords

• ethanol
• fermentation
• immobilization
• Saccharomyces cerevisae
• water hyacinth