Study On The Removal Of Pyrene From Soil By Extracellular Polymeric Of Mycobacterium BFZG

Extracellular polymeric substances(EPS),which are high molecular weight polymer secreted by bacteria or fungi, are widely applied in many fields, such as mineral engineering,environmental engineering, food industry and biological medicine, due to their unique physicochemical properties. A number of bioremediation techniques including composting, biological reactor, phytoremediation and integrated microbial-phtoremediation have been developed and applied in contaminated soil remediation, and the microbial effects played an essential role in all the above bioremediation process. Along with the thoroughly research of bioremediation technology for polluted soils, the application of EPS in the process of pollutant removal has become an important issue.Therefore, this topic selected EPS extracted by highly-efficient-degraded bacteria of and typical polycyclic aromatic hydrocarbons-pyrene as the research object, to study the role of EPS in the removal of pyrene from soil,in order to understand the mechanism of bioremediation of soil polluted by polycyclic aromatic hydrocarbons.The main contents of the research are as follows:(1) The role of Mycobacterium BFZG EPS in the dissolution of pyrene was analyzed by study on solubilization of pyrene in solution. The results indicated that:EPS could significantly in crease dissolution of pyrene insolution, helping bacterical capture and degradation of pyrene.Dissolution of pyrene was associated with EPS concentration, temperature and pH.Compared with property of other surfactant/surfaceactive agent, protein in EPS was the main influencing factor in dissolution of pyrene.(2)The role of Mycobacterium BFZG EPS in thedesorption of pyrene was analyzed by study on desorption-adsorption of pyrene in soil solution. The results showed that:EPS could significantly decrease the amount of pyrene residual in soil.Residual amount of pyrene was associated with EPS concentration, temperature and pH.(3)Key dioxygenase gene in pyrene degradation was found in Mycobacterium BFZG.By comparing amount of 16 S DNA, dioxygenase gene, bacterial protein and EPS in different pyrene that BFZG had a good adaptability to pyrene,and two kinds of genes were not affected by 120 mg/L pyrene treatment;moreover, bacterial and EPS protein bands were changed in different pyrene concentration.(4)EPS played an important role in removal of pyrene in soil.EPS made residual of pyrene in soli decrease and more free in the liquid phase by adsorption with soil;moreover,EPS increased the solubility of pyrene in liquid solution,helping bacterica to absorb, utilize and degrade pyrene.