Effects of Phosphate-limitation on Glycerol Biosynthesis and Intracellular Phosphorus Accumulation of Candida glycerinogenes

Abstract:

Effects of phosphate limitation on glycerol biosynthesis and intracellular phosphorus accumulation of Candida glycerinogenes were studied by recycling yeast cells. The results demonstrated that, throughout the fermentation of yeast cells recycled, intracellular phosphorus accumulation gradually decreased when yeast cells were re-inoculated from the suitable phosphate or rich phosphate medium to the low phosphate medium; while intracellular polyPhosphate accumulation rapidly increased after yeast cells were re-inoculated from the low phosphate medium to the suitable phosphate or rich phosphate medium. When yeast cells were re-inoculated from the suitable phosphate medium to the low phosphate medium at the fourteenth or thirty-eighth hour, glycerol yields on glucose of 60.9% or 61.4% could be achieved with a productivity of 2.03 g/(L·h) or 2.23 g/(L·h). These phenomena proved that it is necessary for glycerol overproduction by C. glycerinogenes to limit phosphorus concentration in fermentative medium, which provides an important basis for its glycerol production by repeated fed-batch fermentation.

Key words:Phosphate limitation, Candida glycerinogenes, Glycerol biosynthesis, polyPhosphate (polyP)