Isolation and Identification of Naphthalene-degrading Strain and Its Degradation Characteristics

A dominant naphthalene-degrading strain,named ZJ2H,which can utilize naphthalene as sole carbon source was isolated from activated sludge of a coking plant.The strain ZJ2H was identified as Ralstonia mannitolilytica by morphological observation,physio-biochemical test,16S rDNA sequence and phylogenetic analysis.Effect of initial concentration of naphthalene solutions,inoculating dosage,pH,temperature,salinity and shaking rates of rocking bed on degradation efficiencies were investigated.Results showed that the strain ZJ2H performs best in the conditions of initial concentration of naphthalene solutions 40 mg/L,inoculating dosage 10%~25%(V/V),temperature 30~35 ℃,pH 7.0,salinity less than 3%,shaking rates of rocking bed 120~160 r/min.