限磷对产甘油假丝酵母甘油合成与胞内磷积累的影响

研究了磷酸盐限量对产甘油假丝酵母甘油合成与胞内磷积累的影响。结果表明, 当酵母细胞从适磷或富磷培养基转接入低磷培养基时, 发酵过程中胞内积累的磷逐渐减少; 而当菌体从低磷培养基转接入适磷或富磷培养基时, 发酵过程中胞内聚磷酸盐的积累量迅速增加。当细胞在第14小时和第38小时从适磷培养基转接入低磷培养基时甘油得率分别高达60.9%和61.4%, 而甘油产率则分别为2.03 g/(L·h)和2.23 g/(L·h)。这些现象说明限制发酵培养基中的磷浓度是产甘油假丝酵母高产甘油的必要条件, 并为其反复分批发酵法生产甘油提供了重要依据。

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

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.