速生杨二步超低酸水解液发酵制取燃料乙醇的研究

以速生杨二步超低酸水解方法获得的水解液为原料,在28℃、100 r/min等发酵条件下,选择热带假丝酵母(C.2.637)和酿酒酵母(S.2.699)分别对第一步和第二步水解液进行了发酵制取燃料乙醇的研究,并考查了Ca(OH)2中和、过中和、活性炭吸附等预处理方法及菌种预适应驯化对乙醇转化率的影响。结果表明:热带假丝酵母能够更好地利用第一步水解液生成菌体,适合生产单细胞蛋白;菌种驯化后发酵速度和乙醇转化率均有提高,尤其是以酿酒酵母发酵第二步水解液,乙醇转化率由14.45%增至39.37%;Ca(OH)2过中和的方法处理后的水解液,乙醇转化率有所增加;以五碳糖为主同时含有六碳糖的速生杨第一步水解液,假丝酵母发酵产乙醇的效果好于酿酒酵母。

Study on Production of Fuel Ethanol from Poplar Hydrolyzate Obtained by Two-step Super-low Acid Hydrolysis

Choosing hydrolyzate of poplar as fermentation material,which was obtained by two-step super-low acids hydrolysis,fuel ethanol production was studied by using Candida tropicalis 2.637 and Saccharomyces cerevisiae 2.699 respectively.Simul-taneously the influences to the ethanol yield by various pretreatment methods,such as Ca(OH)2 neutralization,over-neutralization,active carbon adsorption and yeast-training were carried out.The experimental results show that C.tropicalis 2.637 is suitable to the first-step hydrolyzate rich in pentose to produce single cell protein.Yeast-training can improve fermentation speed and increase ethanol yield,especially to the second step hydrolyzate through which ethanol yield was increased from 14.45 % to 39.37 % by S.cerevisiae 2.699.The over-neutralization of hydrolyzate by Ca(OH)2 improved ethanol yield,too.Therefore,for the hydrolysis of the first-step hydrolyzate,which contains mainly pentose and accompanied with hexose,more ethanol can be obtained by C.tropicalis 2.637 than by S.cerevisiae 2.699.