Identification,optimization Of Conditions And Characteristics Research Of A High-efficiently Phenol Degradable Salt-tolerant Strain Acinetobacter Sp.zhtI

Phenolic wastewater has a complex composition and a wide range of sources.Some of the phenol wastewater contains a large amount of salt(Ca²⁺,Mg²⁺,Cl^-and Na⁺,et al),which greatly increases the difficulty of wastewater treatment.Phenol,as a prototoxin,causes serious pollution to the environment.Long-term consumption of water or food contaminated with phenol will cause great harm to human health.Therefore,the treatment of phenol wastewater has always been a hot research topic at home and abroad.In order to screen for the effective treatment of phenol wastewater by salt-tolerant phenol-degrading strain,a high-efficiently phenol degradable salt-tolerant strain was isolated from the water treatment samples of Haili?Changde?Pesticide Chemical Co.,Ltd.,The morphological characteristics,physiological and biochemical reactions and 16S rDNA were used to identified the strain.The effects of different environmental factors on the degradation of the strain were studied,and the degradation conditions were optimized by the response surface methodology.phenol kinetic of the strain was studied and so did its degradation characteristics.Main results are as follows:?1?A salt-tolerant phenol-degrading strain zhtI was obtained from the selective medium with a salinity of 35 g/L and phenol as sole carbon source.Based on its morphological characteristics,Individual characteristics,physiology and biochemical reaction,analysis of its16S rDNA gene,zhtI was identified as a strain of Acinetobacter sp..?2?Glucose concentration,phenol concentration,pH value were indentified as three main factors affecting the biodegradation of phenol by Plackett-Burman experimental.Response surface analysis showed that the phenol degradation rate could reach 93.23%in the condition of phenol concentration 801.6 mg·L^-1,glucose concentration 5.56%,pH7.3,inoculum 6%,temperature 30?,salinity 3%,cultured 72h.?3?The strain zhtI maximum tolerated concentration of phenol was 1700 mg·L^-1,and the strain zhtI degradation of phenol kinetic model was in line with the typical substrate inhibition model,and its kinetic parameters were:?max=2.142,K_S=126.952 mg/L,Ki=476.191 mg/L.?4?Degradation of substrate broad-spectrum experiments found that strain zhtI could be treated with phenol,nonylphenol,sodium dodecyl sulfate,diphenyl semicarbazide,benzenediol phosphate,catechol,o-phenylenediamine,P-hydroxybenzoic acid et al as the sole carbon source.The hydroxylated enzyme,catechol 1,2-dioxygenase fragment and tetrahydropyrimidine gene fragment were amplified by the specific primers from the genomic DNA of strain zhtI.The accumulation of tetrahydropyrimidine is an important mechanism of strain zhtI to tolerate high salt stress.The degradation of phenol by strain zhtI is related to its own plasmid,but its salt-tolerance ability was independent of its plasmid.