弯曲隐球酵母N-11合成微生物油脂的代谢调控研究

摘要

通过摇瓶发酵实验考察不同调控方式对弯曲隐球酵母N-11菌体生长和积累油脂的影响.主要从改变培养基组成中的小分子限制性因素(氮、磷、硫)、调控脂质合成关键酶(苹果酸酶)的酶活性以及采取不同发酵模式(分批培养与补料培养)研究影响微生物积累油脂的因素并对其进行优化.结果表明:当碳氮比为180.2∶1、碳磷比为61∶1、碳硫比为2 413.4∶1时,酵母菌油脂产量及含油率达到最高,分别为5 g/L、68.30％,5 g/L、65.99％及5.53 g/L、67.11％;培养基中苹果酸酶抑制剂——芝麻酚的添加可以显著降低酵母积累油脂的能力;补料培养不仅可以显著提高油脂产量(由4.25 g/L增加至9.17 g/L),含油率也从65.28％增加至74.92％.%The effects of different regulation methods on the growth and oil accumulation of Cryptococcus curvatus N-11 were investigated by shake flask fermentation experiment.The small molecular limiting factors (nitrogen,phosphorus and sulfur) in the medium composition were changed,and the enzyme activity of the key enzyme (malic enzyme) were regulated,and different fermentation modes (batch culture and fed culture) were adopted to study the factors that affected the accumulation of microbial oil and optimize these factors.The results showed that under the conditions of C/N 180.2∶ 1,C/P 61 ∶ 1 and C/S 2 413.4∶ 1,the oil production and oil content in the yeast cells reached the highest,which were 5 g/L and 68.30％,5 g/L and 65.99％ and 5.53 g/L and 67.11％ respectively.The addition of sesamol,a malic enzyme inhibitor,in the culture medium could significantly reduce the ability of yeast to accumulate oil.Fed culture could not only significantly improve the oil production from 4.25 g/L to 9.17 g/L,but also increase the oil content from 65.28％ to 74.92％.