聚乙烯醇生物降解性能的研究

【作者】 董丽娟；

【导师】 王风云； 雷武；

【作者基本信息】 南京理工大学 ， 物理化学， 2005， 硕士

【摘要】 本文中,由自然界所得的混合菌群证实了对三种型号的聚乙烯醇都能有效的进行降解。而且,也通过实验证明,在混合菌群的培养液中,存在着聚乙烯醇降解酶,并通过酶反应和核磁共振证实了在培养液中存在聚乙烯醇氧化酶而不存在醣酶。还分别研究了混合菌群及胞外酶降解聚乙烯醇时,分子量和醇解度对聚乙烯醇降解的影响。CO₂呼吸测定实验证明,根据聚乙烯醇的醇解度的不同,混合菌群的降解存在滞后,而分子量对降解没有明显影响。通过核磁谱图不同氢的化学位移,探讨了聚乙烯醇的降解机理。另外,从混合菌群中筛选出三种菌落,通过对这三种菌落降解性能的比较,证实了其中一种由球菌和杆菌组成的共生菌落的降解效率最高;通过对此菌落的驯化实验,及对驯化后降解曲线的分析,证实了驯化可使细菌在较短的时间达到较高的降解效率。随后,研究了酸碱度和有机物对降解效率的影响,进一步讨论了如何选择优良降解条件,以及在实际工业运用中应注意的问题。更多还原

【Abstract】 In this paper, the selected mixed microbial was approved having the biodegradability of the three kind of PVA. Experiments carried out in the presence of the culture supernatant clearly demonstrated the presence of a PVA degrading enzymatic system in the solution. The dependence of PVA biodegradation on polymer molecular weight and degree of hydrolysis was investigated in the presence of a PVA-degrading microbial population and of the relevant extracellular enzyme. Enzymatic assays and ¹H NMR excluded the presence of extracellular esterases in the culture supernatant but confirmed the presence of oxidases. Respirometric tests of CO₂ carried out in the presence of the selected microbial population evidenced a limited but significant delay in the mineralization profile depending upon the degree of PVA hydrolysis, whereas no remarkable effect by molecular weight was detected. By the ¹H NMR chemical shifts of the different groups, it was discussed about the biodegradation mechanism of the PVA. Otherwise, there bacterial colonies were isolated from the PVA-degrading microbial population. After measuring the biodegradability of the selected microbes, it was found that the colony of the microbes which were composed of one kind of coccus and one kind of bacillus had relatively higher ability of degrading PVA. By the experiments of domestication and analysis the curve of biodegradation, it was proved that the domestication could improve the biodegradability of the microbes in a relatively short time. After that some researches were done about the influence of the organic compounds and pH value on the degree of biodegradation. By these experiments, it was discussed how to choose better conditions of biodegradation in order to put it into practical industrial use.更多还原