玉米芯NaOH预处理及同步糖化发酵生产乙醇和木糖醇  

Corncob NaOH Pretreatment and Ethanol and Xylitol Preparation by Simultaneous Saccharification and Fermentation

作　　者：张溪 朱莉伟[1] 邓立红[1] ZHANG Xi;ZHU Liwei;DENG Lihong(College of Material Science and Technology,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学材料科学与技术学院,北京100083

出　　处：《生物质化学工程》2024年第3期10-16,共7页Biomass Chemical Engineering

基　　金：北京林业大学教育教学改革与研究项目(BJFU2023JY061)。

摘　　要：以玉米芯为原料,先进行NaOH预处理,然后分别单独接种热带假丝酵母(Candida tropicalis)、同时接种酿酒酵母(Saccharomyces cerevisiae)和热带假丝酵母及分步接种热带假丝酵母和酿酒酵母进行同步糖化发酵生产乙醇和木糖醇。结果表明:高温碱性条件会使纤维素和木聚糖大量损失,合适温度下的碱性条件能保留全部纤维素和大部分木聚糖,并去除几乎全部木质素,提高纤维素酶解得率。100℃时以10 g/L氢氧化钠水溶液处理玉米芯,预处理后,其纤维素无损失,纤维素酶解效率大幅提高,且能回收64.5%的木聚糖。预处理后的玉米芯接种酵母进行糖化发酵时仅接种C.tropicalis,增加纤维素酶添加量,能促进乙醇的生产而削弱木糖醇生产;同时接种C.tropicalis和S.cerevisiae,能同时促进乙醇和木糖醇的生产;先接种C.tropicalis并加入木聚糖酶,24 h后再加入S.cerevisiae和纤维素酶,能进一步促进木糖醇的生产。10 g预处理玉米芯(质量浓度为200 g/L)中先加入90 U木聚糖酶和10%(以发酵液总体积为基准)热带假丝酵母种子,24 h后再加入纤维素酶20 FPU/g(以纤维素计)和10%(以发酵液总体积为基准)酿酒酵母种子,可生产38.4 g/L的乙醇和15.4 g/L的木糖醇。Corn cob was pretreated with NaOH.Then,Candida tropicalis was inoculated separately,C.tropicalis and Saccharomyces cerevisiae were inoculated simultaneously,and C.tropicalis and S.cerevisiae were inoculated step by step.They were subjected to simultaneous saccharification and fermentation to produce ethanol and xylitol.The results indicated the high temperature and alkaline conditions could result in a large loss of cellulose and xylan.The alkaline conditions at suitable temperature could retain all cellulose and most xylan,remove almost all lignin,and improve enzymatic hydrolysis rate of cellulose.When corn cob was treated with sodium hydroxide solution at 100℃,there was no loss of cellulose,the hydrolysis efficiency of cellulase was greatly improved,and 64.5%xylan could be recovered.Inoculating C.tropicalis only and increasing the amount of cellulase could promote the production of ethanol and weaken the production of xylitol.The simultaneous inoculation of C.tropicalis and S.cerevisiae could promote the production of ethanol and xylitol.The production of xylitol could be further promoted by inoculating C.tropicalis and adding xylanase 24 h before adding S.cerevisiae and cellulase.Adding 90 U xylanase and 10%(based on the total volume of fermentation broth)C.tropicalis seeds to 10 g pretreated corn cob(with concentration of 200 g/L),24 h later adding 20 FPU/g cellulase(based on cellulose)and 10%(based on the total volume of fermentation broth)S.cerevisiae seeds,38.4 g/L ethanol and 15.4 g/L xylitol could be produced.

关 键 词：酿酒酵母 热带假丝酵母 纤维素损失 纤维素酶 

分 类 号：TQ35[化学工程]