SELECTION OF THERMOTOLERANT YEAST STRAINS FOR SIMULTANEOUS SACCHARIFICATION AND FERMENTATION OF CELLULOSE

A total of 58 yeast strains from 12 genera were assayed for their ability to grow and ferment carbohydrates in standard Durham tube test at 40, 43, and 46.degree. C. Based on the kinetic parameters for glucose fermentation in shaken flask cultures, the strain Fabospora fragilis CCY51-1-1 was chosen for further studies. It reached about 56.0 and 35.0 g ethanol/L from .apprx. 140 g glucose/L at 43 and 46.degree. C in less than 48 h, respectively. Trichoderma reesei cellulase preparation (400 FPU/L) had no distinct efect on the ethanol yield and biomass production by the selected strain in the first 12 h fermentation at 46.degree. C. Later a negligible decrease in both yields was observed. It was found that Fabospora fragilis did not grow or produce ethanol at 46.degree. C as the initial ethanol concentration overcame 40 g/L.