Analysis Of Marine BTX-Degrading Bacteria, The Diversity And Degradation Characteristics

BTEX is one of important components in the petroleum hydrocarbon, due to its reasonable water-solubility, being common organic pollutant in the water. BTEX had already been confirmed to be the strong carcinogen by the World Health Organization. Along with a great deal of oil pollutant impacting into marine, petroleum pollution has brought about a long-term and bad influence to ocean environment and ecosystem system. Purpose of this thesis is to analyze to the diversity of BTX-degrading bacteria fRom nearshore and deep-sea marine environments and to characterize the predominant PAH-degraders. By contrast, the thesis also studied on BTX-degraders from land environment .By enrichment with benzene, toluene,or xylene as the sole carbon source, 15 bacteria with the ability of benzene, toluene or xylene degradation were isolated from the active sludge of a life sewage treatment plant, nearshore sea water of Xiamen and west Pacific sediment, respectively. Sequence analysis of 16S rDNA identified that they belonged to Pseudomonas, Acinetobacter, Rhodococus and Bacillus, respectively. The optimal temperature, salinity and pH of these strains were examined,and found that they all grew in the circumstances from 18℃ to 37℃, 0% to 3% NaCl, and pH 7-10. But the strains from different samples had great difference in the optimal circumstances. The optimal temperature of the strains from Xiamen sewage plant and Xiamen nearshore sea water was 28℃, they could not grow in the low temperature (4℃), while, the isolates from deep sea had a wide range of temperature, their optimal temperature is 18℃, they could grow in the low temperature (4℃). The optimal salinity range from Xiamen sewage plant and marine environment is 0-2% and 2%-5% respectively. These results incarnated the response of microorganisms to their living environments. Moreover, all strains had wide adaption to pH, with the range of pH7-10.The isolates showed degradation of 67.7%~94.2% of 0.1%(V/V) benzene or toluene within 72hrs in a medium with benzene or toluene as the sole carbon source . Moreover,...