菊芋秸秆高浓度物料分步糖化及乙醇发酵

Separated saccharification and ethanol fermentation of Jerusalem artichoke with high solid loading

菊芋是生物能源和生物炼制的新型原料作物,具有和其他作物不同的秸秆组成.为了解菊芋秸秆的生物转化情况,本研究首先比较了NaOH-H_2O_2、瞬间弹射蒸汽爆破(ICSE)及NaOH-H_2O_2和ICSE联用等3种预处理方法,证明对于菊芋秸秆NaOH-H_2O_2预处理法简单高效.进一步研究显示,NaOH-H_2O_2预处理过程中水洗一次即可显著促进酶解和后续发酵.利用分批补料和补加纤维素酶的方式进行高物料浓度条件下预处理菊芋秸秆的分步水解和乙醇发酵,当物料浓度达到30%(m/V)时,水解72 h的葡萄糖和木糖浓度分别可达143.6 g/L和36.2 g/L.利用木糖-葡萄糖共发酵重组酿酒酵母菌株LX03在菊芋秸秆水解液中进行乙醇发酵,发酵72 h乙醇最高浓度达66.2 g/L(8.27%,V/V),且发酵总糖利用率达86.9%.本研究利用菊芋秸秆水解液发酵获得较高的乙醇产量,为进一步利用菊芋秸秆进行高效生物炼制及高浓度纤维素乙醇生产提供了参考.(图3表1参23)

As a novel alternative lignocellulosic feedstock for biorefinery, Jerusalem artichoke stalks （JAS） has different cellulosic compositions from the stalks of agriculture crops, however, studies on the bioconversion of JAS are still limited. It is crucial to optimize the pretreatment technology of JAS and to further study fuel ethanol fermentation from JAS hydrolysate with recombinant Saccharomyces cerevisiae. In this work, JAS was pretreated using NaOH-H202, instant catapult steam explosion （ICSE）, and sequential ICSE and NaOH-H202 treatment. It was found that NaOH-H202 pretreatment method was the best for the pretreatment of JAS. The results also showed that washing the pretreated JAS for only one time was sufficient, significantly benefited the hydrolysis and fermentation process, and reduced waste water. Finally, separated hydrolysis and fermentation of pretreated JAS with high solid loading by feeding of both JAS substrate and enzyme was investigated. When the solid loading reached 30% （m/V）, 143.6 g/L glucose and 36.2 g/L xylose were obtained after 72-hour hydrolysis, When the hydrolysate was subject to fermentation by employing the recombinant S. cerevisiae strain LX03, ethanol titer of 66.2 g/L （8.27%, V/V） was achieved with total sugar consumption ratio of 86.9%. The results in this study provide insights for the improvement of bioconversion efficiency of JAS and high titer cellulosic ethanol production by recombinant S. cerevisiae using JAS.