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

Shafaghat Hoda (School of Chemical Engineering, Noushirvani University of Technology, Babol, Iran)
Najafpour Ghasem D. (School of Chemical Engineering, Noushirvani University of Technology, Babol, Iran)
Rezaei Sirous Pouya (School of Chemical Engineering, Noushirvani University of Technology, Babol, Iran)
Sharifzadeh Mazyar (Islamic Azad University, Ayatollah Amoli Branch, Amol, Iran)

Saccharomyces cerevisiae (PTCC 24860) growth on pretreated sugar beet molasses was optimized via statistical approach. In order to liberate all monomeric 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 cell growth were investigated by design expert software with application of 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, maximum ethanol production of 14.87 g/L was obtained.

Keywords: optimization, ethanol, pretreated molasses, Saccharomyces cerevisiae, fermentation, response surface methodology