| The wide use of traditional polymer materials has brought great harm to the global environment.To solve this problem,more and more researchers are beginning to pay attention to the research and development of biodegradable materials.Polyvinyl alcohol has a wide range of applications in many fields such as food packaging,glass manufacturing and medical industries for its good mechanical properties and biodegradability.It's early found that polyvinyl alcohol and its synthetic materials could be degraded by microorganisms.And the discovered PVA-degrading bacteria,by now,mainly concentrate on the phyla level of Pseudomonas,while studies on other microorganisms are few.In this experiment,we analyzed the microbial communities during the degradation course of polyvinyl alcohol material,and determined the dominant bacteria.Finally,the strains that could degrade polyvinyl alcohol were obtained through screening and separation,and their characteristics were analyzed preliminarily.The main contents and resoults of this paper are as follows:1.Polyvinyl formal foams were degraded into small pieces after being buried in compost for a period of time.The FTIR showed that carbonyl group(s)formed in the molecule from the degraded samples.it proved that the poly vinyl formal foams were of good biodegradability.2.The total OTU of The alpha diversity of OTU samples was analyzed.The diversity of microbial species gradually decreased during the burial course,and the Shannon value of the microorganisms from 3 months,2 years and 3 years degraded sample were 2.29,1.81 and 1.18 respectively,and the Simpson value of the three samples were 0.58,0.28 and 0.27.The diversity of microorganisms was becoming lower according to the degradation of poly vinyl formal foams.3.At the level of Family,the most dominant bacteria in the 3 year degraded sample were Bacillaceae,Clostridiaceae and Paenibacillaceae,and the relative abundances were 82.00%,15.45% and 1.13%.The most dominant bacteria in the 2 year degraded sample were Enterobacteriaceae,Bacillaceae,Clostridiaceae and Paenibacillacea,and the relative abundances were 74.71%,16.92%,5.77% and 1.90%.The most dominant bacteria in the twoyear degraded sample were Bacillaceae,Sphingobacteriaceae,Nocardiodaceae,Corynebacteriaceae and Enterobacteriaceae,the relative abundances were 63.90%,7.12%?5.55%,5.08% and 3.70%.It indicates that there may remain some poly vinyl alcohol degrading bacteria in Bacillaceae and Enterobacteriaceae.4.Isolation of 2 strains of good degrading ability was conducted,and they were separately identified as Bacillaceae sp.DG01,Bacillaceae sp.DG02,Paenibacillus sp.DG03 and Paenibacillus sp.DG04 16 S rDNA sequence analysis.The biodegradation rates of PVA1799 by the four strains were respectively 58.27%,54.47%,29.92% and 46.59%,and the biodegradation rates of PVA1788 by them were 59.70%,74.99%,56.74% and 67.27%.The biodegradation rates of PVA1799 by the 4 strain were much lower than those of PVA1788,it showss that the PVA of higher degree of hydrolysis is harder to degrade by microbes. |
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