Optimization of ethanol production from microwave alkali pretreated rice straw using statistical experimental designs by Saccharomyces cerevisiae

Abstract

Ethanol production from agro-waste provides an alternative energy-production system. Statistical experimental designs were used for optimization of critical nutrients and process variables for ethanol production. The critical nutrients and process variables were initially selected according to a Placket-Burman (PB) design. Selected factors (inoculum level 1-5%, pH 4.5-7, temperature 25-35 °C and urea concentration 0.25-0.75. g/L) were optimized by response surface methodology (RSM) based on a three-level four-factor Box-Behnken design (BBD). Under optimum conditions of inoculum level 3%, pH 5.75, temperature 30 °C and urea concentration 0.50. g/L maximum ethanol production obtained 13.2. g/L from microwave alkali pretreated rice straw with ethanol productivity 0.33. g/L/h. Under optimum conditions ethanol production studied at fermenter level and obtained ethanol concentration 19.2. g/L, ethanol productivity 0.53. g/L/h and ethanol yield to consumed sugar 0.50. g/g. These results indicated that ethanol production can be enhanced by optimization of nutritional and process variables. © 2011 Elsevier B.V.