Optimization of Ethanol Production from Palmyra Sap by Zymomonas mobilis ZM4 using Response Surface Methodology (RSM)

     Ethanol is believed to be one of the best alternatives to replace gasoline because ethanol is a renewable source and environmentally friendly. Ethanol can be produced from palmyra sap (Borassus flabellifer) using Zymomonas mobilis ZM4 (NRRL B-14234) that known as a superior bacteria with higher ethanol production efficiency and higher ethanol tolerant. 

     To develop a process for maximum production of ethanol, standardization and optimization fermentation is crucial. The quantitative effects of sugar concentration, urea concentration, and inoculums concentration on ethanol production were optimized using a Box- Wilson central composite design (CCD) experiment. Optimization by the classical method using a single dimensional search involving changing one variable while fixing the others at a certain level is laborious and time consuming, especially when the number of variables is large. 

     Optimization using Response Surface Methodology (RSM) is the one suitable method for identifying the effect of individual variables and for seeking the optimum conditions for multivariable system efficiently. Basically, this optimization process involves three major steps: performing the statistically designed experiments, estimating the coefficient in a mathematical model and predicting the response and checking the adequacy of the model. A high similarity was observed between the predicted and experimental results, which reflected the accuracy and applicability of RSM to optimize the process for ethanol production.