【作者】 章毅君；

【导师】 张晓昱；

【作者基本信息】 华中科技大学 ， 微生物学， 2007， 硕士

【摘要】 利用秸秆进行燃料乙醇的生产,既可以废物利用,也可以缓解当前化石能源日益紧缺的危机。利用白腐菌预处理秸秆,可以提高秸秆在燃料乙醇生产工艺中的糖化效率,而进行白腐菌预处理,一个关键的问题就是开放模式的解决。本论文通过对实验室常用菌株的筛选,成功构建出两类开放体系:(1)本身利于在秸秆上开放生长,但糖化效果不佳的Bp2开放体系;(2)糖化效果好,但却不利于在秸秆上开放培养的2538开放体系。在此基础上,成功地实现了两种开放模式的连续化。培养条件单因子试验结果表明:培养条件中培养时间和接种量对两种开放体系影响效果显著,其中培养天数极其显著;而基质含水量与含水pH值不显著,但两因素对糖化率的影响存在着一个有利范围。通过正交试验优化出Bp2开放体系的最佳培养条件为:培养时间为15天, pH值为7.0,接种量为38.5%,基质含水量为77.8%;2538开放体系的最佳培养条件为:培养天数为15天, pH值为3.0,接种量为42.9%,含水量为71.4%。在最佳条件下,两者糖化率分别为32.3%和44.6%,分别比对照提高了26.2%和69.8%。通过对Bp2和2538开放体系的连续实验实现了初步的放大,Bp2可以成功实现三批连续开放,使得糖化效果明显提高。2538连续开放虽然随着培养批次的增加糖化效果变差,但可成功实现五批连续开放,且糖化效果比对照明显提高。影响连续开放培养批数的一个关键原因是体系中杂菌的增多,以致影响白腐菌在连续开放培养体系中占据主导生态位。本论文首次成功构建了秸秆固体发酵两类连续开放预处理模式,探讨了培养条件对开放体系糖化效果的影响规律,优化了两类体系的最佳培养条件,对秸秆转化燃料乙醇研究的放大开放预处理提供了一定的理论和技术支持。更多还原

【Abstract】 Production of ethanol by using corn straw can not only reduce the straw wastes, but also alleviates the pressure of the lacking of fossil fuel. The pretreatment of corn straw by white-rot fungus can improve the saccharification ratio of the production of fuel ethanol. A key technology of the biopretreatment is non-sterile conditions of the fermentation system.In this paper, two kinds of non-sterile fermentation systems have been excogitated by screening 8 staple basidiomycetes in the lab :1, The Pleurotus ostreatus system., which has growth superiority in corn straw. But the saccharification efficiency of this system is discontented.2,the Echinodontium taxodii 2538 system, which make against the growth of the fungi. But the saccharification efficiency of this system is the best.Based on the study of the relationship between fermentation conditions and saccharification efficiency, it is indicated that the influences of different factors differed a lot. Culture time is the most distinctive factor orthogonal experiment, inoculation volume is the second. Water content and pH value is indistinctive. Based on the orthogonal exprements , The optimized fermentation condition of the Pleurotus ostreatus system is: culture time 15 days, inoculation volume 38.5%, Water content 77.8%, pH value 7. The optimized fermentation condition of the Echinodontium taxodii 2538 system is: culture time 15 days, inoculation volume 42.9%, Water content 71.4%, pH value 3. Under the optimized fermentation condition, saccharification efficiency of the Pleurotus ostreatus system is 32.3%, which improved by 26.2%. saccharification efficiency of the Echinodontium taxodii 2538 system is 44.6%, which improved by 69.8%.Based on the study of the continuous pretreatments by white rot fungi under non-sterile conditions, it is indicated that Pleurotus ostreatus system can continue three times with steady saccharification efficiency, the Echinodontium taxodii 2538 system can continue 5 times at least. The key factor of the continuous pretreatments by white rot fungi under non-sterile conditions is the amount of the infectant microorganism.The study contrived the continuous pretreatments by white rot fungi under non-sterile conditions for the first time, and found out the relationship between fermentation conditions and saccharification efficiency. This paper provided important theoretic and practical significance for the ethanol production by using corn straw.更多还原