EVALUATION OF ETHANOL PRODUCTION BY OSMOTOLERANT YEAST ISOLATED FROM HONEY, CANE SYRUPS, MOLASSES, AND OTHER HIGH SUGAR CONTENT SUBSTRATES

A collection of 398 yeast strains has been obtained using endemic and unique sources of fruit juices, industrial syrups, honey, and other high sugar content substrates, either natural or man made, products and by-products from Mexico. The osmotolerance of the strains was assessed by plate assay both in salt and glucose. Strains were classified according to their osmotolerance in low, medium or highly tolerant to high sodium chloride or glucose concentrations. The cultures were tested in glucose media (MDS) using a low concentration (10%) and a high (40%) glucose concentration. The best alcohol producers were tested in larger flasks and the fermentation products analyzed by HPLC-IR and HPLC-DAD. Osmotolerant, ethanol and organic acid producing strains, were detected, which provided for unusual catabolic abilities. Proposed biotechnological applications for selected strains are presented and discussed.