关键词: 乙酸, 玉米秸秆, 预处理, 氢氧化钠, 响应面分析

Abstract: 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.

Key words: acetic acid, corn stover, pretreatment, sodium hydroxide, response surface methodology