Comparison of Luffa cylindrica L. sponge discs and Ca-alginate gel beads as immobilized matrices of Saccharomyces cerevisiae for bio-ethanol production from sugarcane molasses

The production of bio-ethanol from cane molasses (diluted to 15% sugar, w/v) was studied, using the yeast, Saccharomyces cerevisiae immobilized in luffa ( Luffa cylindrica L .) sponge discs and in Ca-alginate gel beads. At the end of 96 h fermentation, the ethanol yields were 64.67 ± 0.016 and 65.21 ± 0.030 g/l molasses, with luffa and Ca-alginate entrapped S. cerevisiae cells exhibiting 89.90 ± 0.008 and 91.86 ± 0.072% sugar conversion, respectively. There was no statistically significant difference [Fisher’s least significance difference (LSD)] between the two immobilized systems in both sugar utilization (t = 0.254, p < 0.801) and in ethanol production (t = -0.663, p < 0.513). Key words : Bio-ethanol, cell immobilization, fermentation, molasses, Saccharomyces cerevisiae.