鹰嘴豆孢克鲁维酵母利用菊芋原料同步糖化与发酵生产乙醇

菊芋含有大量的菊粉多糖,且种植简单、产量高,是极具开发价值的替代玉米等粮食作物生产燃料乙醇的原料。文中研究了鹰嘴豆孢克鲁维酵母Y179利用菊芋原料同步糖化与发酵生产乙醇。鹰嘴豆孢克鲁维酵母Y179具有高效分泌菊粉酶的能力,摇瓶试验显示Y179酵母能够利用完全由菊芋原料配制而成的培养基良好生长并发酵产生乙醇。通气及温度对乙醇产量影响明显,相对厌氧环境对Y179酵母发酵产乙醇具有促进作用,30℃发酵温度相对37℃和42℃更有利于乙醇产量提高。种子液培养时间及接种量对乙醇产量影响较小。在5 L发酵罐中以10%(V/V)量接入预培养36 h的Y179种子液,发酵液完全由菊芋干粉配制而成,总糖含量22%(W/V),30℃不通气,300 r/min搅拌,发酵144 h时,乙醇浓度达到12.3%(V/V),糖醇转化效率86.9%,糖利用率大于93.6%。初步研究结果显示鹰嘴豆孢克鲁维酵母Y179在利用菊芋原料生产乙醇方面具有良好应用前景。

Simultaneous saccharification and fermentation of Jerusalem artichoke tubers to ethanol with an inulinase-hyperproducing yeast Kluyveromyces cicerisporus

Jerusalem artichoke tubers with inulin as major component are potential feedstock for fuel ethanol production, and Kluyveromyces cicerisporus Y179 expressing high level of inulinase is suitable for ethanol production with this feedstock by simultaneous saccharification and fermentation approach. In this article, the impact of inoculum, aeration and temperature on ethanol production by the yeast was studied. The experimental results illustrated that inoculum with different levels and seed collected at different cultivation times had negligible effect, while anaerobic conditions enhanced ethanol production, and more ethanol was produced by the yeast at 30°C than at 37°C or 42°C. The medium using Jerusalem artichoke tuber meal as sole component with 22% (W/V) total sugars was inoculated with 36 h-precultured seed at 10% (V/V), and the batch fermentation was conducted in a 5 L fermentor at 30°C with a stirring speed of 300 r/min under anaerobic conditions. After 144 h, 12.3% (V/V) ethanol was produced and the yield of ethanol from sugars was 86.9% of its theoretical one, with 93.6% sugars consumed. These results indicate that K. cicerisporus Y179 is a promising candidate for industrial ethanol production using Jerusalem artichoke tuber feedstock.