ISOLATION OF A NAPHTHALENE-DEGRADING PLASMID AND ITS TRANSFER IN WASTEWATER TREATMENT SYSTEM
萘降解性质粒的筛选及其在炼油污水处理场中的转移

A pseudomonas strain S13, capable of utilizing naphthalene as its sole carbon source, was isolated from the activated sludge of a wastewater treatment plant of Wuhan Oil Refinery. Plasmid detection, curing, transfer by conjugation and DNA-DNA molecular hybridization experiments demonstrated that the naphthalene-degrading ability of the pseudomonas strain S13 was plasmid borne. In situ Nah+ plasmid (pWE2) transfer by conjugation was conducted in modified membrane diffusion chambers in the aeration basin at the wastewater treatment plant and the results indicated that the pseudomonas strain S13 could transfer its naphthalene-degrading piasmid(pWE2) to another pseudomonas strain T9, isolated from the same source as the S13 was. The transfer frequency was 8.7×10-8 in the wastewater treatment system, compared with 1.6×10-7 observed in the laboratory. Pseudomonas strain T9 could grow on naphthalene after obtaining the plasmid(pWE2), suggesting the possibility of degra-dative plasmid transfer in natural environment.