Tuesday, April 20, 2010
LL Conference Facility (Hilton Clearwater Beach)
In this study, the response methodology was carried out to identify the significant effects of medium components towards ethanol production using engineering strain E.coli KO11 in batch culture. Ethanol concentration was considered as response and the five factors concerned were corn steep liquor, ferric sulfate, magnesium sulfate, ammonia sulfate, potassium phosphate monobasic and dibasic mixtures. Statistical analysis of the results showed that the potassium phosphate salt mixture is the only significant factor among total five factors considered. A quadratic model was developed to describe the relationship for ethanol production performance. The high correlation between the predicted and observed values indicted the validity of the model. The optimal conditions achieved for five factors were 14g/L corn steep liquor, 80 mg/L ferric sulfate, 1066 mg/L magnesium sulfate, 8.16 g/L ammonia sulfate, 0.68 g/L potassium phosphate monobasic and 0.44 g/Lpotassium phosphate dibasic mixture. The evaluation experiments under optimal conditions showed that the highest ethanol concentration was 31.5 g/L, which was even 5 g/L higher than that from same concentration of gluconate in LB media.