Isolation Of Phenanthrene Degrading Bacteria From Contaminated Soil And Their Effects On Phenanthrene Degradation

Polycyclic aromatic hydrocarbons are widespread pollutants and can be released to atmosphere, soils, foods and water. Exposure to PAHs would be hazardous to human health and environments and therefore eliminating them is considered a priority in many countries. Phenanthrene is one of the simplest aromatic hydrocarbons, that contains a "bay-region" and a "Kregion", which are of importance in terms of reactivity and Carcinogenicity. So it has been taken as a model compound for studies on PAHs. Work on phenanthrene biodegradation not only is beneficial to eliminate the contamination of phenanthrene from environments, but also can be valuable in understanding the biodegradation mechanism and feasibility of other PAHs. It is useful for providing control measurements for bioremediation of soil and other environment contaminated by PAHs.In this paper, isolation of polycyclic aromatic hydrocarbon -degrad- ing bacteria was conducted in plate medium by selective enrichment culture. Three isolates of C22 , C13 and C8 were obtained by the method of sublimation from contaminated soil; C22 was identified as Bacillus sp. , C13 as Cupriavidus sp. and C8 as Paenibacillus sp. based on analysis of 16S rDNA sequence; Both strains grew well on sole carbon of phenanthrene and degrade it efficiently; The amount of phenanthrene degradation was correlated with the OD value; The results indicated that the ability of phenanthrene-degrading increase greatly when they were used as a mixture; The measurement of phenanthrene degradation by strain C22 indicated that the rate of phenanthrene degradation was the highest at the initial pH 8.0 in medium; Addition of yeast extraction or glucose could promote phenanthrene degradation of C22 strain to different degree; Tween-80 also could promote the degradation of phenanthrene significantly; Compared to phenanthrene alone, the mixture of naphthalene and phenanthrene in medium enhanced the phenanthrene degradation rate of C22 strain; The strain C22 showed catechol 2,3-dioxygenase (C230) enzyme activity induced by PAHs; The growth on Naphthalene and phenanthrene and catechol showed that the strain degrades phenanthrene via salicylate Pathway; The C230 coding gene was amplified with the specific with the specific primer from the strain C22.