SUCROSE-SUPPLEMENTED DISTILLERY SPENT WASH AS A MEDIUM FOR PRODUCTIONOF ETHANOL AT 45-DEGREES-C BY FREE AND ALGINATE-IMMOBILIZED PREPARATIONS OF KLUYVEROMYCES-MARXIANUS IMB3

Ethanol production by the thermotolerant, ethanol-producing yeast stra in Kluyveromyces marxianus IMB3, was compared during growth on sucrose -supplemented laboratory-based media and distillery spent wash from th e Old Bushmill's Distillery Co., Ltd., Co. Antrim, Northern Ireland. F ermentations were carried out using preparations of the free and algin ate-immobilized microorganism as inocula in media supplemented with 2 and 10% (w/v) sucrose. Maximum ethanol concentrations accounted for 75 -99% of the maximum theoretical yield and in all cases maximum concent rations obtained using the spent wash were similar if not slightly hig her than those obtained on the sucrose-supplemented yeast growth media . In addition, the highest concentrations of ethanol were produced by the alginate-immobilized biocatalyst on both types of media. Analysis of exhausted media in the spent wash-based systems demonstrated signif icant decreases in the total organic carbon content following fermenta tion. These results confirm our earlier suggestion that ethanol produc tion based on this microorganism in a recycle system may provide a mor e cost-effective means of disposing of whiskey distillery spent wash.