Effects of phosphorus and nitrogen limitations on continuous production of glycerol in a multistage cascade bioreactor by Candida krusei

Abstract

A multistage cascade culture was used for the continuous production of glycerol by an osmophilic yeast Candida krusei. The effects of phosphorus and nitrogen limitations on glycerol production were investigated. The results showed that the fermentation performance was improved under either phosphorus or nitrogen limitation. A maximum glycerol yield of 24.7% based on the glucose consumed and a maximum glycerol yield of 7.1 g g −1 based on the biomass were achieved under the optimum nitrogen limitation. The maximum productivity for the whole system under the optimum phosphorus limitation was 11.3% higher than that under the optimum nitrogen limitation. This indicated that the nitrogen limitation benefited the improvement of glycerol yield based on the glucose consumed and the production ability of glycerol per unit biomass but the phosphorus limitation favored the increase of productivity. The glycerol/glucose yield and the glycerol/biomass yield could be further improved under the dual limitations of phosphorus and nitrogen, but the biomass yield and the productivity were reduced.