DOI: 10.36347/sajb.2013.v01i07.004

Pages: 363-373

Optimization of the batch culture of Saccharomyces cerevisiae for cell growth and ethanol production via anaerobic condition, an analysis using a three level, three factorial Box–Behnken designs was performed. Intact dry yeast was used as it is relatively easily obtained. The Box–Behnken design can be a useful approach to determine the optimum conditions for maximum production. Three separation parameters, Glucose % (X1), pH (X2), and Incubation temperature 0C (X3), were chosen to observe the effect. The responses were detected via spectrophotometer and gas-chromatography. Standard curve of concentration vs. OD of yeast cell was done to help further study. The optimum conditions and process validation were determined using statistical regression analysis, sigma and contour plot diagrams. Under low pH, high glucose concentration and temperatures around 30°C, ethanol production was highest. The optimum conditions were established to be 3% glucose media of pH 6.0 at an incubation period of 30 hour at 33ºC. Maximum cell growth found OD630 1.45 and ethanol production 2%. The fact behind this distribution of efficiencies was due to glucose concentration and incubation temperature manly. The method was validated by randomly selecting values from combinations. It was also observed that R2 values were over 0.99 which refers the result was almost accurate. By using the analysis technique, the prediction of responses was satisfactory and process verification yielded values within the ±5% range of the predicted efficiency. The relationship between coded variables and responses are better understood by examining the series of 3D line plots i.e. contour plot and Sigma plot 12.0.