Screening of a chlorimuron-ethyl-degrading strain and chlorimuron-ethyl-contaminated soil bioremediation
WANG Hai-lan1, ZANG Hai-lian1, CHENG Yi2, AN Xue-jiao1, XU Chun-hong3, LI Chun-yan1
1. College of Resources and Environment, Northeast Agricultural University, Harbin 150030, China;
2. College of Science, China Agricultural University, Beijing 100083, China;
3. Mudanjiang Youbo Pharmaceutical Co., Mudanjiang 157000, China
A chlorimuron-ethyl-degrading strain (LCY-4), which was isolated from the sewage sludge of a sewage treatment tank in the Jiangsu Hormone Research Institute, was identified as Rhodotorula mucilaginosa based on morphological characteristics and 26S rDNA sequence analysis. The results of these studies showed that the strain exhibited a chlorimuron-ethyl degradation rate of 87.33% at the end of a 5-d incubation period in mineral salt medium with 100mg/L chlorimuron-ethyl under the optimal degradation conditions (2.5% inoculum size, 28℃ and pH 6.0). The optimal degradation conditions of strain LCY-4 in chlorimuron-ethyl-contaminated soil (containing 10mg/kg chlorimuron-ethyl) were a 2.5% inoculum size, 25℃, pH 6.0 and a 30% soil water content. In these experiments, a chlorimuron-ethyl degradation rate of 90.74% was observed at the end of a 30-d incubation period. Soil remediation experiments showed that the application of the chlorimuron-ethyl-degrading strain LCY-4 could alleviate the phytotoxicity of chlorimuron-ethyl on wheat seedlings. In chlorimuron-ethyl-contaminated soil with 10mg/kg chlorimuron-ethyl, the rate of seed emergence, plant height, root length and fresh weight in the treatment group with the addition of LCY-4 were higher than those in the control group without the addition of LCY-4 (P < 0.05).
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