能源甜菜乙醇发酵的耐高温菌种筛选及工艺优化

Screening High Temperature Tolerant Yeast Strains and Technological Optimization of Ethanol Fermentation of Energy Beet

利用能源甜菜进行乙醇发酵已引起人们重视。由于发酵温度对乙醇发酵效果影响较大,为了探讨不同菌种对发酵温度高低的适应性,筛选适应高温发酵的优良菌株,本研究首先利用温度单因素筛选出耐高温菌种HADY,45℃时乙醇转化率仍达81.68%;菌种ADY在31℃时乙醇转化率最高。然后利用Plackett-Burman设计和响应面分析法(RMS)从与发酵相关的9个因素:底物质量浓度、料液比、加菌量、营养盐添加量、加磷量、pH值、转速、发酵温度和发酵时间中依次筛选出底物质量浓度、发酵温度和加磷量3个主要影响因素。优化后的工艺参数为:底物质量浓度为12%、料液质量比1:1、加菌量15%、营养盐0.5、加磷量0.9%、pH值5.0、转速130r/min、发酵温度37℃和发酵时间44h。此条件下的乙醇转化率为89.43%。

It has been an interesting topic using energy beet to ferment ethanol. Because temperature would affect ethanol fermentation of energy beet greatly,in order to explore the adaptability to high temperature of the different strains and to screen better yeast to ferment in the high temperature,in this study,at first,by the single factor,temperature,the yeast HADY was screened to be tolerant to high temperature,such that when the fermentation temperature was 45℃,the translation rate of ethanol was 81.68%. However,the translation rate of ethanol of ADY was the highest at 31°C. Secondly,three main factors were screened out from nine factors related to fermentation by Plackett-Burman design and response surface methodology,including substrate concentration,ratio of solvent to material,added HADY amount,nutrient salts,phosphorus addition amount,pH value,rotational speed,fermentation temperature and fermentation time. The three main factors are substrate concentration,fermentation temperature and phosphorus addition amount. The optimized technological parameters of HADY are as follows：substrate concentration （mass fraction） 12%,mass ratio of solvent to material 1：1,added HADY 15%,nutrient salts 0.5,added phosphorus 0.9%,pH 5.0,rotation speed 130r/min,fermentation temperature 37℃ and fermentation time 44 hours. It is shown that the translation rate of ethanol is 89.43%.