Process optimization for citric acid production from raw glycerol using response surface methodology

Statistical experimental design was applied for the optimization of medium constituents for citric acid production by Yarrowia lipolytica NCIM 3589 in submerged fermentation using raw glycerol as the carbon source. Response surface methodology (RSM) involving central composite design (CCD) was adopted to evaluate the amount of citric acid produced by most important factors, such as carbon concentration, nitrogen concentration, and salt solution concentration. A second order polynomial regression model was fitted and was found adequate with R of 0.9485. The optimum conditions were found to be carbon concentration 38.77 g/L, nitrogen concentration 0.401 g/L, and salt solution concentration 12.3 % (v/v). Citric acid production at these optimum conditions was 13.41 g/L.