Isolation and characterization of xylose-utilizing yeasts for ethanol production

In this research work, twenty two xylose-utilizing yeasts were isolated from various sources. Although all isolates could assimilate all tested sugars, they have variations in sugar fermentation pattern. In temperature tolerant activity, almost all yeast isolates could grow well at 40°C. Weak growth of seven yeast isolates (YP3, YP4, YP7, YP8, YP11, YP12 and YP15) was occurred at 45°C. Yeast isolates could grow at pH range (pH3 to pH6) and their optimum growth was occurred at pH3 and pH4. Moreover, isolated yeast strains were tolerant to ethanol concentration of 5%. Some yeast isolates could grow at 7% ethanol concentration. Among all isolates, YP5 and YP14 could produce 1.1% and 1.5% of ethanol concentration respectively at 14 days incubation period and YP17 could produce 0.6% at 3 days incubation period.