Process Optimization And Mechanism Analysis Of The Biodegradation Of Polyvinyl Alcohol

In recent years,many researchers have conducted a lot of research on the biodegradation of polyvinyl alcohol and PVA-based materials.The research mainly focused on the screening of polyvinyl alcohol-degrading strains,separation and purification of degrading enzymes,and related degradation enzyme genes.Although great progress has been made,there are still some problems.For example,the degradation efficiency of polyvinyl alcohol is still relatively low,and the biodegradation mechanism is not clear enough and perfect,making it difficult to apply the technology of microbial treatment of polyvinyl alcohol to practice.In this study,we mainly improve the biodegradation rate of polyvinyl alcohol by Bacillus thuringiensis.DG02 from our laboratory in two aspects.One is by optimizing culture conditions of the strain and the other is oxidative modification.At the same time,we analyzed structure changes of polyvinyl alcohol during biodegradation by using GPC,FTIR and UV-VIS technology.And the main research contents and results of this article are as follows:1.Under the optimized optimal conditions,the degradation rate of polyvinyl alcohol reached 70.27% after 7 days,which is 10.86% higher than before.2.The transparent circles experiment shows that Bacillus thuringiensis.DG02 has the ability to degrade polyvinyl alcohol with different degrees of polymerization or alcoholysis,like PVA1788,PVA1792,PVA1799,PVA1088,PVA1888 and PVA2488.3.The degradation rate of PVA1788 by Bacillus thuringiensis.DG02 was about 30% higher than the degradation rate of unmodification.4.The biodegradation of polyvinyl alcohol conforms to the first-level degradation kinetics through experimental determination of the biodegradation process of polyvinyl alcohol.5.Through infrared and ultraviolet spectroscopy analysis,some substances like aldehydes and ketones may be produced during the biodegradation process of polyvinyl alcohol,and its structure needs to be further verified.6.After 7 days' degradation by Bacillus thuringiensis.DG02,the weight average molecular weight of PVA1788 decreased from 37143 to 29987.And with the extension of the biodegradation time,the molecular weight gradually decreased.