The Factors Influencing The Biodegradation Of Phenol By Ring-opening Cleavage Pathway And Its Effect On Promoting Mineralization Efficiency

Phenols are widely used in the production in various chemical industries,because of its various kinds and extremely toxic,it can cause great harm to environment.Phenols are easily hydroxylation and ring-opening cleavage through several ways by Pseudomonas stutzeri N2,resulting in a wide range of intermediate degradation products and difficult to achieve pollutant mineralization.This study is aimed at exploring and revealing the ways of biomineralization of phenol.The research of this paper is of practical significance for the solution of high concentration phenol pollutants in effluent.The flask experiment and modern analysis method are used in the research.Investgate the effect of phenol ring-opening cleavage way,intermediate degradation products and exocytosis of active protein on the mineralization characteristics of phenol compound by using Pseudomonas stutzeri N2.The results are as follow:(1)The biotransformation products of phenol degradation by Pseudomonas stutzeri N2 can stimulate the cells growth,but the accumulation or coexistence of biotransformation products obviously affect the promoting effect.The promotion effect of catechol is most obvious,expecially when the accumulation amount is about 5mg/L,it can not only promote the degradation of phenol and the growth of Pseudomonas stutzeri N2 cells,but also increase the rate of phenol mineralization.(2)The Pseudomonas stutzeri N2 degrade phenol through ortho or meta ring-opening cleavage pathway.Improving the proportion of ortho ring cleavage,are more likely to improve the mineralization efficiency of Pseudomonas stutzeri N2 when using phenol as the carbon source.The role of promoting effect of catechol achieved by increasing the activity of catechol 2,3 dioxygenase degradation of Pseudomonas stutzeri N2.(3)When using phenol as carbon source,it could induce Pseudomonas stutzeri N2 to secrete six extracellular active protein with molecular weight in the range of 10-50 KDa.These extracellular macromolecules can promote the degradation and mineralization of phenol.(4)Rhodococcus ruber FF could degrade phenol,and destroy phenol aromatic ring only through the ortho ring cleavage pathway,which is conducive to the removal of TOC in biodegradation system.When mixed cultivate of Rhodococcus ruber FF and Pseudomonas stutzeri N2,the cells grew well and no inhibition was observed.When inoculation rate of Rhodococcus ruber: Pseudomonas stutzeri N2 is 2:1,the effect of promoting mineralization is the most obvious.Compared with the pure Pseudomonas stutzeri N2,the removal rate of TOC in the phenol degradation system was increased by about 40%...