异常汉逊酵母发酵乙酸乙酯条件优化和代谢研究

Optimization of fermentation conditions of Hansenula anomala for ethyl acetate production and study on the metabolic pathway

以高粱和大曲为原料,用一株异常汉逊酵母NZ-19-1为发酵剂,通过正交试验优化了其发酵原料配比及发酵条件。结果表明,该酵母菌在葡萄糖含量27%的高粱水解液中,辅以4%的大曲,初始pH值为5.0,装料系数0.25,25℃下采用静置方法发酵13天,可获得富含乙酸乙酯含量的酒醅,初步建立了一种乙酸乙酯含量较高的勾兑用白酒的生产工艺。通过对这株高产菌特征性代谢产物和醇酰基转移酶的研究,得出该菌株合成乙酸乙酯的途径是:先利用葡萄糖生成乙酸和乙醇,乙酸在HSCoA的作用下激活为乙酰-CoA,与乙醇在醇酰基转移酶的催化作用下合成乙酸乙酯。这一结果可为今后将该菌株运用于富含乙酸乙酯的勾兑用白酒的生产提供技术参考。

Using kaoliang and Daqu as raw materials, the material composition for the fermentation ofHansenula anomala NZ-19-1 was optimized by orthogonal test, as well as the fermentation conditions. The results showed that when H. anomala NZ-19-1 was inoculated in 27% kaoliang extract with the addition of 4% Daqu and material coefficient of 0.25 and fermented statically at 25℃ for 13d, the fermented grains would be rich in ethyl acetate. Furthermore, a production processing of high-ethyl acetate-containing Chinese liquor for blending was developed. Besides, the characteristic metabolites and alcohol acyltransferase of H. anomala NZ-19-1 were studied. It was indicated that the synthesis pathway of ethyl acetate in H. anoma/a NZ-19-1 stated with the synthesis of acetic acid and ethanol from glucose, and then the acetic acid was activated by HSCoA to be acetyl-CoA, finally, the acetyl-CoA and ethanol were synthesized to yield ethyl acetate by the catalysis of alcohol acyltransferase.