一步法发酵菊芋生产乙醇

利用马克斯克鲁维酵母(Kluyveromyces marxianus)YX01具有菊粉酶生产能力且乙醇发酵性能良好的特点,直接发酵菊粉生成乙醇.在摇瓶中考察了该菌株最适发酵温度,进而在2.5L发酵罐中考察了通气量和底物浓度的影响.实验结果表明:该菌株最适发酵温度为35℃;在通气量为50 mL/min和100 mL/min时菌体生长加快,发酵时间缩短,但在不通气条件下糖醇转化率明显提高;在菊粉浓度235 g/L时,发酵终点乙醇浓度达到92.2 g/L,乙醇对糖的得率为0.436,为理论值的85.5%.在此基础上,使用近海滩涂种植海水灌溉收获的菊芋为底物,以批式补料方式直接发酵菊芋干粉浓度为280 g/L的底物,发酵终点乙醇浓度为84.0 g/L,乙醇对糖的得率为0.405,为理论值的80.0%.这些研究工作,为以菊芋为原料的燃料乙醇技术开发奠定了基础.

One-step Ethanol Fermentation with Kluyveromyces marxianus YX01 from Jerusalem artichoke

A unique one-step ethanol fermentation process was developed with the inulinase-producing strain Kluyveromyces marxianus YX01. Firstly, the impact of temperature on ethanol fermentation was investigated through flask fermentation, and the temperature of 35oC was observed to be the optimum to coordinate inulinase production, inulin saccharification and ethanol fermentation. And then, the impact of aeration and substrate concentration was studied through batch fermentation in the 2.5 L fermentor, and the experimental data indicated that the average ethanol fermentation time was decreased at the aeration rates of 50 mL/min and 100 mL/min, but higher ethanol yield was obtained under non-aeration conditions with more substrate directed to ethanol production. The ethanol concentration of 92.2 g/L was achieved with the substrate containing 235 g/L inulin, and the ethanol yield was calculated to be 0.436, equivalent to 85.5% of its theoretical value. Finally, Jerusalem artichoke grown in salina and irrigated with seawater was fermented without sterilization treatment, 84.0 g/L ethanol was obtained with the substrate containing 280 g/L dry Jerusalem artichoke meal, and the ethanol yield was calculated to be 0.405, indicating the Jerusalem artichoke could be an alternative feedstock for grain-based fuel ethanol production.