Several factors affecting erythritol production from glycerol by Yarrowia lipolytica Wratislavia K1 strain were examined in batch fermentations. Ammonium sulfate, monopotassium phosphate, and sodium chloride were identified as critical medium components that determine the ratio of polyols produced. The central composite rotatable experimental design was used to optimize medium composition for erythritol production. The concentrations of ammonium sulfate, monopotassium phosphate, and sodium chloride in the optimized medium were 2.25, 0.22, and 26.4 g L(-1), respectively. The C:N ratio was found as 81:1. In the optimized medium with 100 g L(-1) of glycerol the Wratislavia K1 strain produced 46.9 g L(-1) of erythritol, which corresponded to a 0.47 g g(-1) yield and a productivity of 0.85 g L(-1) hr(-1). In the fed-batch mode and medium with the total concentration of glycerol at 300 g L(-1) and C:N ratio at 81:1, 132 g L(-1) of erythritol was produced with 0.44 g g(-1) yield and a productivity of 1.01 g L(-1) hr(-1.)
Keywords: Yarrowia lipolytica; erythritol; glycerol; optimization; response surface methodology model.