Isolation And Identificaiton Of Aniline-degarding Strain And The Study Of Degradation Characteristics And Metabolism

With the rapid development of China’s industry, in waste water, a lot ofcyclic aromatic compounds are discharged into the water. Aniline is a typicalsubstance among them and it is a basic material in the production of chemicalproducts, which have been widely applied to different fields, such as organicpigment, pesticide and explosive. However, aniline has high toxicity and couldcause serious damage in the nervous system, the liver function and therespiratory system of human body. Because of volatile, it makes the governanceof aniline harder and harder. At present, the physico-chemical method ofactivated carbon adsorption and ozone catalytic oxidation is being used in thetreatment of aniline wastewater widely. It is simple and takes effect quickly, but,the effluent water quality is not stable and it will cost higher energy. Therefore,microbial treatment technology has a good development prospect in anilinewastewater. Because this method costs little and is easy to use, what’s more, ithas a good effect on water treatment. Therefore, more and more people payattention to the biological way in wastewater treatment.This experiment based on activated sludge samples in the aeration tank ofLu Cheng sewage treatment plant. After enrichment, domestication andseparation, we got a strain which had a great ability in aniline degradation. Itwas named Z1temporarily and could grow with aniline as the sole carbonsource and nitrogen source quickly. Combined with morphological andphysiological characteristics and the molecular biology identification of16SrDNA, finally the strain Z1was identified as Pseudomonas sp.. Then the effect of growth, COD, NH4+-N and degradation of aniline were investigated duringdegradation process, when changing some experiment conditions such asenvironmental factors, the composition of culture medium, inoculation amount,second carbon source and nitrogen source. We found the optimum growth anddegradation condition of strain Z1was pH6.0~8.0,30℃and0.1%~1.0%salinity. Under this condition, Z1was able to almost degrade400mg/L anilinewithin16h and degradation rate was99%. When the aniline initial concentrationwas1300mg/L, the maximum degradation rate of aniline was41.4mg/(L h)and it could grow in the medium containing1800mg/L aniline. The optimalconcentration ratio of aniline and phosphate was between1:1and2:1;inoculability was15%(v/v); With the condition of low temperature or highconcentration of aniline, methanol could effectively improve the effect ofgrowth and degradation of aniline as additional carbon source, the optimalconcentration ratio of aniline and methanol was2:1. Fe2+and Mg2+couldpromote the growth of strain Z1and has a very important role in the process ofaniline degradation. On the contrary, other trace elements had no use. About61.6%aniline-derived nitrogen was released as ammonia in the process ofaniline degradation and at the same time there were more than95%of COD wasremoved. It could remove ammonia nitrogen, with heterotrophic nitrificationbacteria Alcaligenes faecalis C16, mixed culture. The result was mixed bacteriacould reduce aniline from400mg/L to9mg/L within24h and ammonianitrogen concentration remained at2.1mg/L, OD600was1.423. The best initialconcentration of degrading aniline and ammonia nitrogen was800mg/L.In addition, considering the complexity of real wastewater, it also studiedthe degradation situation of other aromatic compounds. Therefore, we studiedthe adaptability of phenol and the metabolic effect of phenol and aniline bystrain Z1. The results showed that Z1could grow with phenol as sole carbonsource at the concentration up to500mg/L and the maximum degradation rate of phenol was12.2mg/(L h). When aniline and phenol was compounded inenvironment, phenol had an inhibitory effect on the metabolism of aniline withstrain Z1. When the concentration of phenol was more than88mg/L, theinhibitory effect was obvious and it was becoming more and more outstandingwith the increasing of phenol concentration. When the substrate was more than400mg/L, Z1did not grow and the pollutants were not degraded almost. Addingammonium chloride could solve the degradation problem, it was beneficial tothe growth of Z1and the compound pollutants degradation. Both aniline andphenol were almost degraded after36h and the economic level of ammoniumchloride was113mg/L.