PCR-DGGE for determination on high effective strains of degrading chlorophenols

In order to identify the dominant degrading 2, 4-dichlorophenol (2, 4-DCP) and 2, 4, 6-trichlorophenol (2, 4, 6-TCP) microbes in the immobilized anaerobic-aerobic progress, analyze their degrading mechanism, the microbes samples were collected separately from the inlet and outlet of the anaerobic-aerobic reactor. The combination of Polymerase Chain Reaction(PCR)and Denaturing Gradient Gel Electrophoresis(DGGE)were used to separate and identify the mixed microbes. Analyzing the DNA electrophoresis results, studying the PCR product of 16S rDNA-V3 fragments, analyzing and identifying the immobilized microbe gene sequence by and sequencing of the DGGE map, it is ascertain the dominant strains by matching gene sequence of the National Center for Biotechnology Information database. These results show that four anaerobic and facultative anaerobic strains degrade 2, 4-DCP and 2, 4, 6-TCP effectively: Clostridium sp., Enterobacteriaceae sp., Escherichia sp. and Burkholderia cepacia., which are all facultative anaerobic-aerobic. The 2, 4-DCP and 2, 4, 6-TCP degrading mechanism are concluded. 2, 4-DCP and 2, 4, 6-TCP are degraded anaerobic dechlorinatedly, in which an monooxygenase and oxidoreductase catalyze the initial steps. Monooxygenase oxidizes 2, 4, 6-TCP to 2, 6-dichloro-p-benzoquinone, which is chemically reduced to 2, 6-dichloro-p-hydroquinone. Then, monooxygenase oxidizes the latter to 6-chloro-2-hydroxy-p-benzoquinone, and at last, into water, carbon dioxide, and little molecules.