Thermotolerant yeast for simultaneous saccharification and fermentation of cellulose to ethanol

Abstract

Ten promising microbial strains were screened for glucose fermentation over the temperature range of 37-47°C, and five temperature-tolerant yeasts (Saccharomyces cerevisiae SERI strain (D5A), S. uvarum, and Candida genera acidothermophilium, brassicae, and lusitaniae), were chosen for SSF evaluation on Sigmacell-50 cellulose with Genencor 150 L cellulase enzyme. Brettanomyces clausenii (Y-1414) was included for comparison to previous studies both by itself and in mixed culture with S. cerevisiae (D5A). Good conversion rates were achieved at temperatures as high as 43°C with C. brassicae and S. uvarum; mixed cultures of either of these yeasts with the thermotolerant cellobiose fermenting yeast C. lusitaniae achieved higher rates and yields than any of the three yeasts alone. However, the mixed culture of B. clausenii and S. cerevisiae at 37°C achieved as high conversion rates and higher yields than any of the other yeasts tested. © 1988 The Humana Press Inc.