用于生物制氢的玉米秸秆协同预处理工艺实验研究

发布时间：2018-07-06 17:13

  本文选题：玉米秸秆 + 纤维素降解　； 参考：《河南农业大学》2015年硕士论文

【摘要】：目前,我国的大部分农作物秸秆未被合理开发利用,造成了资源的浪费与环境污染。而丰富的纤维素资源可通过直接或者间接的途径来生产氢气。因此在我国研究开发农作物秸秆纤维素转化技术将其用于制氢具有很大的优势,对于解决能源短缺和保护环境有着重要意义。但是受限于纤维素降解成本高,产氢效率低的因素,光合制氢的探索道路仍然很漫长。产黄纤维单胞菌能够产生纤维素酶降解农作物秸秆,产生的还原糖和小分子酸可以用于光合细菌制氢。本文研究了首先使用稀硫酸预处理玉米秸秆,然后调节pH值,加入已经培养好的产黄纤维单胞菌菌液,利用其产生的纤维素酶继续降解玉米秸秆,光合细菌利用降解液进行光合产氢的实验。对今后的秸秆的预处理技术以及光合产氢技术进一步的研究有重要的参考价值。研究的结论总结如下:(1)首先,通过单因素实验设计,对酸处理阶段的工艺条件进行了优化。得出结论:还原糖含量随着硫酸的浓度增加,处理时间延长,温度升高而增加。当固液比为1:10,硫酸的质量分数为8%,预处理时间为60min,温度为121℃时,还原糖含量累积最多,最多为888.29mg。(2)生物预处理阶段所选的纤维素降解细菌为产黄纤维单胞菌,属于纤维单胞菌属,在蛋白胨-牛肉膏琼脂上的菌落通常凸起,淡黄色,属于化能异养型细菌,可以进行发酵代谢,能够产生多种纤维素酶。实验测得玉米秸秆在发酵60h,产酶活性最强。(3)对产黄纤维单胞菌降解玉米秸秆纤维素的工艺条件固液比、pH值和温度进行了优化。得出了以下结论,玉米秸秆与菌液的固液比(质量与体积的比值g/L)为15%,p H为6时,温度为25℃,还原糖含量最高,还原糖浓度为3.26g/L。(4)通过单因素实验设计,对玉米秸秆进行化学-生物协同预处理的工艺条件进行了优化,得出结论:当玉米秸秆先进行硫酸处理之后,再进行生物预处理。玉米秸秆协同预处理的时间缩减为12天,还原糖含量大幅度增加。(5)通过正交实验设计,对玉米秸秆的协同预处理工艺条件进行了优化,得出结论:最佳的工艺条件为化学预处理阶段中硫酸浓度为8%,处理时间为150min,温度为121℃,生物预处理初始pH值为5,产黄纤维单胞菌菌液量为30ml。还原糖浓度最高,最高为1520mg,产氢量最多为640ml。
[Abstract]:At present, most crop stalks in China have not been developed and utilized reasonably, resulting in waste of resources and environmental pollution. The abundant cellulose resources can produce hydrogen directly or indirectly. Therefore, the research and development of crop straw cellulose conversion technology for hydrogen production has great advantages in China, which is of great significance to solve the energy shortage and protect the environment. However, due to the high cost of cellulose degradation and low hydrogen production efficiency, the exploration of photo-hydrogen production is still a long way. Xanthomonas xanthomonas can produce cellulase to degrade crop straw and produce reducing sugar and small molecular acid which can be used to produce hydrogen by photosynthetic bacteria. In this paper, corn straw was pretreated with dilute sulfuric acid first, then adjusted pH value, and then added to the culture of Xanthomonas aeruginosa, and the cellulase produced by it was used to degrade corn straw. The experiment of hydrogen production by photosynthetic bacteria using degradation solution was carried out. It has important reference value for the further research on the pretreatment technology of straw and the hydrogen production technology of photosynthesis in the future. The conclusions are summarized as follows: (1) at first, the process conditions of acid treatment stage were optimized by single factor experimental design. Conclusion: the content of reducing sugar increases with the increase of sulfuric acid concentration, treatment time and temperature. When the ratio of solid to liquid is 1: 10, the mass fraction of sulfuric acid is 8, the pretreatment time is 60 min, and the temperature is 121 鈩，

本文编号：2103537