嗪草酮降解菌Rhodococcus sp. MA的降解特性及固定化应用

Strain MA was isolated from farmland soil, which was capable of degrading 74.8% of 50 mg•L^-1 within 5 d. The optimum degradation temperature and pH were 30 ℃ and 7.0, respectively. Strain MA was identified as Rhodococcus sp. MA based on morphological observation, physiological characteristics and its 16S rRNA gene sequence. The degradation product of metribuzin was identified as deamino-metribuzin by GC-MS. The orthogonal test results showed that the degradation efficiency of metribuzin was the highest (71.2%) when using 3% sodium alginate as the embedding agent, 2% CaCl₂, embedding ratio of 8:1 and fixed time of 6 h. When unimmobilized bacteria were used in the bioremediation experiment, the removal rates of metribuzin in lake and pond water (15 mg•L^-1) were 72.1% and 69.9%, respectively. The removal rates were increased to 87.3% and 82.6%, respectively with immobilized bacteria, suggesting promising application prospect in bioremediation area.