Optimal growth of Saccharomyces cerevisiae (PTCC 24860)on pretreated molasses for the ethanol production: The application of the response surface methodology

Saccharomyces cerevisiae (PTCC 24860) growth on pretreated sugar beet molasses was an optimized via statistical approach. In order to liberate all mo-nomeric sugars, pretreated sugar beet molasses with dilute acid was obtained. The influence of process parameters such as sugar concentration, nitrogen source, pH and incubation time on the cell growth were investigated by a design expert software with the application of a central composite design (CCD) under response surface methodology (RSM). The optimal culture conditions were pH of 5.3, incubation time of 24 h and medium composition of 35 g reduced sugars, 1.5 g NH₄Cl and 1 g yeast extract per liter of the media. At optimal cell growth conditions and incubation time of 12 h, the maximum ethanol production of 14.87 g/L was obtained.