PRODUCTION OF ETHANOL FROM GUAVA PULP BY YEAST STRAINS

Guava pulp used for ethanol production by three yeast strains containe d 10% (w/v) total sugars and was pH 4.1. Ethanol production at the opt imum sugar concentration of 10%, at pH 4.1 and 30 degrees C was 1.5%, 3.6% and 3.9% (w/v) by Saccharomyces cerevisiae MTCC 1972, Isolate-1 a nd Isolate-2, respectively at 60 h fermentation. Higher sugar concentr ations at 15 and 20% were inhibitory for ethanol production by all tes t cultures. The maximum production of ethanol at optimum natural sugar concentration (10%) of guava pulp, was 5.8% (w/v) at pH 5.0 by Isolat e-2 over 36 h fermentation, which was only slightly more than the quan tity of ethanol produced by Saccharomyces cerevisiae (5.0%) and Isolat e-1 (5.3%) over 36 and 60 h fermentation, respectively. (C) 1997 Elsev ier Science Ltd.