玉米秸秆乙酰基水解产物对乙醇发酵的影响及去除策略

Effects of Hydrolyzate of Corn Stover Acetyl Groups on Ethanol Fermentation and Its Removal Strategy

研究了木质纤维原料在预处理过程中半纤维素上乙酰基水解产生的乙酸对酿酒酵母、树干毕赤酵母乙醇发酵的影响,结果表明乙酸对戊糖、己糖酵母乙醇发酵均产生很大的影响。根据乙酸产生的特点,采用氢氧化钠法去除乙酸而尽量不降解纤维素和半纤维素,从源头上将乙酸与'糖'分开。在单因素(氢氧化钠质量浓度、温度、液固比和时间)试验的基础上,采用响应面分析进一步优化试验,结果表明,上述4个因素的影响从大到小依次为:氢氧化钠质量浓度、液固比、温度和时间。最佳条件为:NaOH 5.45 g/L,液固比13∶1(mL∶g),温度62℃,时间45 min。在此条件下乙酸去除率和木聚糖残留率分别为95.19%和87.80%。

The effects of acetic acid liberated from the hemicellulose acetyl groups during the lignocellulose pretreatment on the ethanol fermentation by Saccharomyces cerevisiae and Pichia stipitis were investigated. The results showed that acetic acid had a significant influence on the fermentation of both pentose and hexose. According to the formation process of acetic acid, sodium hydroxide pretreatment was applied to remove the acetic acid, while cellulose and hemicelluloses were less degraded. This method separated acetic acid from residual polysaccharides from the original source. Based on the results of the single factor experiments （ the concentration of NaOH, treatment temperature, liquid-solid ratio, and treatment time ） , response surface methodology was applied to further optimize the pretreatment conditions. The results showed that the importance sequence of the mentioned 4 factors was followed by the concentration of NaOH, liquid-solid ratio, treatment temperature and treatment time. Under the optimal condition （5. 45 g/L NaOH concentration, 13：1（ mL：g） liquid-to-solid ratio, 62 ℃ treatment temperature, and 45 min treatment time）, the removal ratio of the acetic acid and the retention ratio of xylan was 95. 19 % and 87. 80 %, respectively.