玉米秸秆水解液脱毒处理发酵生产酒精研究

为了找到适宜的玉米秸秆生产酒精工艺,采用水热处理后的玉米秸秆固体与水解液进行酒精同步糖化发酵,研究了预水解后不同pH值以及饱和生石灰法脱毒相结合对酒精发酵的影响。结果表明:当pH值在4.8时,加入100%水解液,由于抑制作用,醪液中酒精质量浓度仅为0.31 g/L(酒精得率9.48%)。预水解后将pH值从4.8分别调整到5.5、6.0和6.5后,酒精得率都有明显提高,最高为pH值5.5时,酒精质量浓度为10.67 g/L。将水解液经过饱和生石灰法脱毒处理,预水解后重新将pH值调整为5.5,酒精质量浓度达到了10.96 g/L(酒精得率57.9%)。与初始pH值4.8时相比,酒精得率提高了近6倍。

Ethanol Production from Detoxified Corn Stover Hydrolysate

After hydrothermal pretreatment of corn stover,solid fraction and hydrolysate were collected separately.To find out the appropriate process for ethanol production from corn stover,ethanol production was evaluated from dried solid fraction and the hydrolysate employed as liquid fraction by baker’ yeast.The effects of different pH value and detoxification on ethanol production were investigated.Firstly,prehydrolysis was performed at 50℃ for 24h.When 100% hydrolysate was added,ethanol content of 0.31g/L(9.48% of theoretical ethanol yield) was obtained based on the cellulose available in the pretreated corn stover due to the existence of acetic acid and furans which are important inhibitors of the fermentation to microorganisms.After prehydrolysis,the initial pH value was adjusted to 5.5,6.0 and 6.5,respectively.The best value obtained was ethanol content of 10.67g/L with addition of 100% hydrolysate at pH value of 5.5.The hydrolysate was overlimed,then prehydrolysized for 24h at 50℃.After prehydrolysis,the initial pH value was adjusted again to 5.5.Ethanol content of 10.96g/L(57.9% of theoretical ethanol yield) was obtained.Ethanol yield increased almost 6 times compared to that at pH value of 4.8.