Abstract
An extractive fermentation for ethanol production was carried out by using immobilized cells of Saccharomyces cerevisiae Kyokai 7 and its lactose-fermentable fusant (strain PN13). Although o-isopropylphenol (OIPP) and o-tert-butylphenol (OTBP) as extractive solvents had relatively large partition coefficients against ethanol (1.4 by weight-based concentration), the solvents were heavily toxic to both yeasts. Some plant oils such as castor oil protected the yeasts from the toxicity of OTBP. Therefore, the ethanol fermentation became feasible even in the presence of OTBP as extractant by using yeast immobilized within alginate gel containing castor oil as protective agent. The ethanol production activity of gel beads containing the oil was not deteriorated through six repeated uses.
