Statistical optimization of culture conditions for 1,3-propanediol by Klebsiella pneumoniae AC 15 via central composite design.

A central composite design was used to study the effect of glycerol, rate of stirring, air aeration and pH on the synthesis of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae AC 15. Among the four variables, glycerol and rate of stirring significantly affected 1,3-PD productivity, whereas air aeration and pH were not effective. A quadratic polynomial equation was obtained for 1,3-PD productivity by multiple regression analysis using response surface methodology. The validation experimental confirmed with the predicted model. The optimum combinations for 1,3-PD productivity was glycerol, rate of stirring, air aeration, and pH of 50 g/l, 318 rpm, 0.6 vvm, 6.48, respectively. The subsequent fed batch experiments produced 1,3-PD of 70 g/l at a fermentation of 30 h.