ENHANCING EFFECT OF ALBUMIN HYDROLYSATE ON ETHANOL-PRODUCTION EMPLOYING SACCHAROMYCES SAKE

The enhancing effect of albumin hydrolysate on ethanol production was investigated in ethanol fermentations using Saccharomyces sake. In bat chwise ethanol production, addition of supplemental albumin hydrolysat e and phosphatidylcholine, or albumin hydrolysate alone, brought about a more than 60% increase in final ethanol concentration (148 or 144 g /L compared with 88 g/L with no supplementation [control] after 72 h). The effect of the supplements is believed to be due to an enhanced al cohol tolerance of cells grown in media containing the supplements. Ce lls grown in media containing albumin hydrolysate were enriched in phe nyalanine, tyrosine, and methionine in their plasma membranes. All thr ee amino acids were also present in considerable amounts in the albumi n hydrolysate. This fact suggests that the three amino acids, which ar e present in albumin hydrolysate, are incorporated into the plasma mem branes of cells. Under ethanol production conditions in which only one amino acid among the components of albumin hydrolysate was excluded, namely phenlalanine, tyrosine, or methionine, significant reductions i n ethanol resulted. (C) 1995 John Wiley and Sons, Inc.