The Isolation And Identification Of A Phenol-degradating Strain And Study On Its Characterization

Phenol is strongly toxical substance and is very harmful to cytoplasm. Its origin existed wildly in our life. It can pollute water,kill fish,do farm to crops and even heavily threat our health. The phenolic compound can only be degraded by several kinds of microbe. Bacteria that can effectively degrade phenolic compound had been isolated from natural environment, they can be pour into waste water treat system and obviously enhanced the effect, therefore, they have extroordinary potential in bioremediation.A bacterial strain JF-10 with high phenol-degradating ability was isolated from sludge. At a concentration of 1000mg/l,this strain degraded phenol completely in 60 hours when it grown in basal medium with phenol as sole carbon source, and when added 0.05% yeast powder, this time can be reduced to 24 hours. JF-10 was Gram negtive, rod, motive, use glucose to produce acid, oxidizing enzyme positive, catalase positive, nitrate deoxidization positive, therefore, it was identified as pseudomonas sp.. The similarity of 16s rDNA sequence between JF-10 and P.citronellolis was 99% ,JF-10 and P.nitroreducens was 97%,JF-10 and P.aeruginosa was 96%. The gyrB gene analysis and physiological and biochemical characters show that this strain was maybe a noval species of pseudomonas.More than 80% of phenol was degraded at pH4.0-9.0 by JF-10,the degrading speed was the fastest when at pH8.0.According to the influence of heavy metal on phenol-degradation,the heavy metal were divided into two group: Cd ²⁺,Co²⁺ did not promote phenol-degradation; while Mn²⁺, Cu²⁺, Ni²⁺,Pb²⁺ promote it on certain concentration. The sensitivity of JF-10 to heavy metal was like this: Co²⁺,Cu²⁺ (minimal inhibitory concentration 0.5mg/l) >Ni²⁺ (minimal inhibitory concentration 1mg/l) >Cd²⁺ (minimal inhibitory concentration 2-5mg/l) >Mn²⁺ (minimal inhibitory concentration 25mg/l) >Pd²⁺ (minimal inhibitory concentration >500mg/l). JF-10 can also degrade p-cresol,benzoic acid and catechol, but did not use α-naphthol,aniline,toluene and O-cresol, the influence of α -naphtho to phenol-degradation was greater than aniline, and toluene had no obvious influence. Phenol may promote O-cresol-degradation by co-metabolism.The phenol-degrading gene located on the chromosome. Using a pair of conservative...