Isolation And Characterization Of Sodium Dodecyl Benzene Sulfonate Degradating Bacteria

Nowadays the research on ecological environment of surfactants has become a focus at home and abroad. The surfactants can seriously harm the aquatic plants, the aquatic animals, and the microorganisms, impair the self-purification capacity of the water body, speed the water eutrophication process. With anionic surfactants Sodium dodecyl-benzenesulfonate (SDBS) was used of great quantity in synthetic detergent industry, it is detected in all kinds of waters all over the world. Therefore, it is of great importance to control and remediation the surfactants SDBS pollution. To develop a simple and effective bioremediation method to treat the anionic surfactants SDBS in environment, the degradation bacterial strain WZR-A was screened and purified from contaminated water, which had a prominent degradation effect on the surfactants SDBS. Through the study, the identification of the strain WZR-A, the influence of various factors on growth and SDBS degradation efficiency, the relative degradation enzymes, the spectrum of substrate and the location of genes correlative to SDBS biodegradation were investigated.The results were listed as follows:1. The isolation of strain WZR-A was able to degrade SDBS effectively. The shape structures of WZR-A was under observation with the aid of the transmission electron microscope (TEM). The result showed that the individual's shape of the degradation bacterial strains WZR-A was long bacillus, and has two polar flagella. The degradation bacterial strain WZR-A was identified as Ochrobactrum anthropi by American Biolog Microstation Identification System. PCR-based cloning and sequencing approaches were applied in the molecular biological identifications on the degradation bacterial strain WZR-A, The results showed that degradation bacterial strain WZR-A belonged to Ochrobactrum sp., rather similar to Ochrobactrum anthropi, and the serial homology degree reached 99%. According to morphology, biochemical characteristics of physiology, Biolog index and molecular biological taxonomy the bacterial strain WZR-A is identified as Ochrobactrum anthropi.2. The degradation bacterial strain WZR-A which can degrade SE)BS very effectively and grow on high concentration solution of SDBS as a sole carbon and energy sources. We studied the effect of substrate concentration, initial pH value and temperature to the growth of strain WZR-A and degradation of SDBS.Through the results of experiments, it showed that various environmental factors,such as different substrate concentration, the initial pH value and temperatureinfluenced the growth and the efficiency of SDBS degradation of the bacterialstrain WZR-A. The study showed that the growth and SDBS degradation effectof the bacterial strain WZR-A was the best at 30℃, with pH 7.0 and thesubstrate concentration being 200mg/L. When SDBS concentration was lowerthan 400mg/L, the degradation rate of strain WZR-A was higher than 80%.3. The results of whole cell protein SDS-PAGE electrophoresis showed that therewere very obvious differences in the total cell protein composition of the strainbetween before and after SDBS inducing. The experiment results showed thatthe relative SDBS degrading enzymes in bacteria stain WZR-A are SDBSinducible, SDBS is not the priority carbon supply of bacteria strain WZR-A. Theenzyme distribution experiment showed that the SDBS relative degradationenzyme in the bacterium was intracellular enzyme. The activities of relativeenzyme in the degradation process were determined showing that thearomatizing cracking was from the catalysis of catechol-1, 2-dioxygenase. Byutilizing plasmid isolating and curing technique, a plasmid was detected and itwas found that the gene relative SDBS degradation may locate in the plasmid.The strain WZR-A is a SDBS degrading bacteria with high capabilities, our studyresult laid a foundation for exploitation of environmental SDBS-remedyingmicroorganism and for building a gene-engineering microorganism to promotebioremediation of SDBS contamination. It can be readily applied to the treatment ofSDBS waste water, especially through some biotreatment technology to enforce itsdegrading abilities.