Isolation, Identification And Characterization Of Bromoxynil-Degrading Bacterial And The Application Of Immobilized Xbj Cells

A bromoxynil degrading strain was isolated from pesticide wastewater treatment pool.This strain was identified as Ochrobactrum intermediu by assembling physiological and biochemical identification combined with16S rRNA sequences.It was designated as XBJ.The stain XBJ growed fast when cultured in LB liquid medium, Strain XBJ grew best in LB culture medium at30℃and pH7.0.When the oxygen supply is sufficient,the growth of the strain is good.The strain could degrade bromoxynil when temperature in the range of15～40℃.The concentration of NaCl had great impact on the growth of stain XBJ, when the concentration of NaCl were0-10g·L-1, the strains growth better, more than15g·L-1, strains are significantly inhibited growth. The strain could highly utilize organic nitrogen source in the test, while had a highest utilization of peptone. In all the carbon sources, the strain could highly utilize glucose.The Strain XBJ are resistant to ampicillin and chloramphenicol, and more sensitive to the other antibiotics.The optimal temperature and pH was30℃and7.0, respectively, degradation rate of bromoxynil in72h was91.87%. Ventilation had no effect on the degradation of bromoxynil,The lower initial concentration, the easier utilization of bromoxynil by the strain, Improving inoculation rate speeded up the degradation of bromoxynil. The metabolites were detected by MS/MS, bromoxynil transformed to3,5-dibromo-4-hydroxybenzoic acid due to the hydrolysis of nitriles, and debromination finally results in the formation of3-bromo-4-hydroxybenzoic acid.Used sodium alginate embedding the bromoxynil degrading strain XBJ, results showed that mechanical strength of immobilized beads best and the degradation of bromoxynil effect was best when the concentration of sodium alginate was2%, the concentration of CaCl2was2%and the packet bacteria were5mL, immobilized time was12h. The degradation rate of immobilized bacteria was slower than the free bacteria, but immobilized bacteria could tolerance pH and temperature in a wider range.