A locally isolated strain of Saccharomyces cerevisiae S1 in peptone, yeast and mineral nutrient (PYN) medium with 100 gL-1 of glucose showed optimum growth at 36 °C and efficient ethanol production at 40 °C. To investigate the effect of soya flour supplementation on ethanol fermentation, PYN medium containing different concentrations of glucose (50 to 400 gL-1) with and without soya flour (26.8 gL-1) were used at 40 °C for 48 h. The above experiment was repeated at different temperatures (40, 43 and 45 °C) for 48 h to find the effect of soya flour supplementation on ethanol production at higher temperatures and sugar levels. The highest ethanol production efficiency (96.5 %) and the highest ethanol yield (149.3 gL-1) with efficient glucose utilization (100 %) was observed in soya flour supplemented medium with a sugar concentration of 300 gL-1at 40 °C. Further, it was observed that at higher temperatures (43 and 45 °C) and higher sugar concentrations, soya flour supplemented media performed well. With 300 gL-1 glucose at 43 and 45 °C the amounts of ethanol produced in soya flour supplemented media was 80 and 30 gL-1, respectively while in unsupplemented media it was only 28 and 18 gL-1, respectively. In glucose (400 gL-1) - PYN medium supplemented with soya flour, 78 (48 h) and 25 gL-1(48 h) ethanol was produced at 43 and 45°C, respectively. The study revealed that supplementation of media with soya flour has not only improved the glucose fermenting capacity but has also increased the efficiency of ethanol production and the ethanol production rate at higher temperatures and high sugar levels.
Balakumar, S., & Arasaratnam, V. (2014). Enhanced production of ethanol by high gravity glucose fermentation at temperatures above 40°C by Saccharomyces cerevisiae S1 using a soya flour supplemented medium. Journal of the National Science Foundation of Sri Lanka, 42(2), 111–117. https://doi.org/10.4038/jnsfsr.v42i2.6987