Construction Of Highly Effective Multiple Microorganisms For Bioremediation Of NP-polluted Water, And Its Degradation Characteristics

Nonylphenol as an important class of endocrine disrupting chemicals(EDCs) has strong disrupting activity. The United Nations Environment Protection(UNEP) puts the Nonylphenol into the list of 27 priority persistent toxic substances. And they are one of the 13 priority hazardous substances listed in European Union. NP-polluted water can not be allowed of optimism in worldwide. Therefore, the biodegradation behaviors of NP have raised public concern.In order to control effectively the NP-polluted water and enrich microbial resources of NP-degrading bacteria, eight bacterial strains were isolated from the activated sludge and the landfill leachate. They could grow with nonylphenol(NP) as the sole source of carbon and energy. Eight NP-degrading bacteria, designated strains WN1,WN2,WN4,WN6,SLY7,SLY8,SLY9 and SLY10.The morphology observation and 16 S rDNA identification revealed that the strains WN1,SLY7 and SLY10 belonged to Pseudomonas monteilii, Pseudomonas stutzeri and Pseudomonas putida, respectively. The strains WN2 and WN6 belonged to Serratia sp. The strains WN4,SLY8 and SLY9 could be assigned to Enterobacter asburiae,Leclercia adecarboxylata and Klebsiella genus respectively within class enterobacteriaceae. Eight NP-degrading bacteria had a better degeneration ability for low concentration of NP, the degradation rate reached over 50% under the initial concentration of NP was 5~20 mg/L.In this study, we detected the eight NP-degrading isolates of degradative genes.The strains WN4,WN6,SLY7,SLY8 and SLY9 contained ALK gene, while the strains WN6 and SLY10 harbored C12 O genes. Multiple microorganisms were constructed from different degradation pathway and bacteria sources. The ratio of the multiple microorganisms ZJF of WN6 to SLY9 to SLY10 being 2:1:2(v/v).The degrading rate of NP(the initial concentration was 20mg/L) by ZJF reached 77.67%, it has made an increase of 15.6% to single cultures and 6.54% to the most efficient single strain.By tests in shaking flasks, the effects of the conditions of degradation of NP by ZJF was studied, ZJF was determined that the optimum conditions were inoculum amount 10%,pH 7.0,and 30℃, shaking velocity 150 rpm. Under these conditions, when the initial concentration was 20 mg/L, the duration was 5 d, the degrading rate of NP reached 77.67%.We also detected the effect of adscititious nutrition on efficiencies degradation and growth of the ZJF. The results showed that glucose and organic nitrogen can be used more efficiently by the ZJF than salicylic acid, ethyl alcohol,NH4 Cl and NaNO3, when the ZJF grow with NP as the source of carbon and energy.Glucose and NaNO3 could inhibit the degradation of NP. As increasing of the concentration, the degradation activity was inhibited. The salicylic acid, ethyl alcohol,NH4 Cl and yeast extract could increase the utilization of NP, but the stimulating effect is very limited.The degradation rate was increased by 9.93% by using the NP-ethanol reserving solution,however, the degradation rate was increased by 4.19% by using the tween-80 reserving solution.We simulated restoration of the NP-polluted Yangtze river water and Ancient Canal water by microbial consortium ZJF. The ZJF could coexist possibly with indigenous microorganism which from Yangtze river water and Ancient Canal water. After a 6-day incubation period,the degrading rate of NP in Ancient Canal water was close to 80%,and the degrading rate of NP in Yangtze river water was 72.84%. When the NP concentration ranged from 5 to 100 mg/L in Yangtze river water and Ancient Canal water,we found that the NP degradation process accorded with first-order kinetic model NP biodegradation rate constants( k) and half-lives( t1/2) by the microbial consortium ZJF ranged from 0.373 to 0.119 day-1 and 2.23 to 7.70 days, respectively.