研究了氮源的种类和添加量对锁掷酵母产胞外多糖的影响,发现(NH4)2SO4有利于胞外多糖的积累,并且随着(NH4)2SO4加入量的增多胞外多糖的分子量趋于降低,在(NH4)2SO4添加量为1.5 g/L时多糖积累量最高为6.89 g/L。采用补料分批发酵时,控制发酵的pH和碳源,72 h多糖积累接近最大值为16.2 g/L。锁掷酵母胞外多糖主要由半乳糖和葡萄糖组成,其组成比例约为1∶2,细胞壁组成主要以葡萄糖、半乳糖和甘露糖为主,其比例接近于2∶1∶1。

The influences of different nitrogen sources on exopolysaccharide production were studied.Among them(NH4)2SO4 is the best candidate to increase the production of exopolysaccharide.Along with the rising amount of(NH4)2SO4,the molecular weight of exopolysaccharide is declining.The maximum production was 6.89g/L with 1.5 g/L(NH4)2SO4.In batch fermentation,pH and carbon source are controlled.The production of exopolysaccharide can reach 16.2 g/L in 72 h.The composition of exopolysaccharide is mainly glucose and galactose.Their proportion is about 1∶2.The polysaccharides contribute to cell wall were consisted of glucose,galactose and mannose,and their proportion is 2∶1∶1.This paper will form the foundation for the study on the physiological function of exopolysaccharide produced by yeast and the derivatization of insoluble polysaccharide.