高甾醇含量热带假丝酵母细胞的培养条件研究

以大豆油脱臭馏出物为唯一碳源，研究了高产甾醇的热带假丝酵母（Candida tropicalis）1253细胞的培养条件。研究发现，无机氮源培养使得菌体甾醇含量显著高于有机氮源培养。当尿素与牛肉膏复合作为氮源时，菌体甾醇含量最高（7.55%）。最佳培养基配方为：脱臭馏出物50.0 g/L、尿素1.0 g/L、牛肉膏1.0 g/L、甘氨酸0.02 g/L、十二烷基苯磺酸钠0.5 g/L、MgSO4 0.1 g/L、K2HPO4 0.2 g/L、KH2PO4 0.2 g/L。最适培养条件为：初始pH 7.0、摇床转速200 r/min。采用上述最适的发酵条件，按10%（V/V）接种量接入热带假丝酵母1253种子液，30 ℃摇床振荡培养96 h。发酵结束后，经过测定，酵母细胞中甾醇含量为8.83%。

Cultivation conditions of yeast cells of Candida tropicalis with higher sterols yield

In this study, the cultivation conditions of yeast cells of Candida tropicalis 1253 with higher sterols yield were investigated using soybean oil deodorizer distillate as single carbon source. The results showed that inorganic nitrogen sources made the cells produce more sterols than organic nitrogen sources. When urea and beef extract were used as co-nitrogen source, the yeast cells had the highest sterol content (7.55%). The optimal composition of the cultural medium was as follow: soybean oil deodorizer distillate 50.0 g/L, urea 1.0 g/L, beef extract 1.0 g/L, glycine 0.02 g/L, SDBS 0.5 g/L, MgSO4 0.1 g/L, K2HPO4 0.2 g/L, KH2PO4 0.2 g/L. The optimal cultivation conditions were initial pH of medium 7.0 and shaker speed 200 r/min. Using the optimal fermentation conditions above, C. tropicalis 1253 was cultivated with 10% inoculum size in a shaker at 30 ℃ for 96 h, and the sterol content in the yeast cells obtained was 8.83%.