Cheng Yue, Fu Qian, Xiong Guixin, Huang Yaning, Li Xu, Yu Qingyue, He Fuxia, Li Haitao, Liu Rongmei
College of Life Sciences, Northeast Agricultural University, Harbin 150030, China.
Microorganisms. 2024 Dec 13;12(12):2568. doi: 10.3390/microorganisms12122568.
Butachlor is a widely utilized acetamide herbicide noted for its systemic selectivity against pre-emergence grass weeds. Butachlor has negative effects on organisms and the environment, so it is necessary to screen degradation strains. In this investigation, strain DC-1 was isolated from soil persistently exposed to butachlor. Through rigorous single-factor and response surface analyses, strain DC-1 exhibited a notable 87.06% degradation efficiency under optimized conditions where the temperature was 32.89 °C, pH was 7.29, and inoculum concentration was 5.18%. It was further hypothesized by LC-MS that the degradation pathway of butachlor by strain DC-1 might be as follows: butachlor undergoes initial deoxygenation catalyzed by dioxygenases to form 2-chloro-N-(2,6-diethylphenyl)-N-methylacetamide, followed by N-demethylation yielding 2-chloro-N-(2,6-diethylphenyl) acetamide, and culminating in conversion to 2,6-diethylphenol. In addition, bioremediation experiments of butachlor-contaminated soil were conducted. The results show that strain DC-1 could degradable 99.23% of butachlor (100 mg·kg) from the soil within 12 d, and soil sucrase, cellulase, and urease activities are promoted by the bacteria. And through high-throughput sequencing, it was concluded that the strain DC-1 was able to influence the relative abundance of certain bacteria in the soil, and make the microbial community in the soil develop in a more stable and beneficial direction. DC-1 thus represents a valuable resource in the realm of butachlor degradation due to its robust efficacy, favorable characteristics, and ecological restorative capabilities, underscoring its promising role in the bioremediation of butachlor-contaminated soils.
丁草胺是一种广泛使用的酰胺类除草剂，以其对出土前禾本科杂草的内吸选择性而闻名。丁草胺对生物和环境有负面影响，因此有必要筛选降解菌株。在本研究中，从长期暴露于丁草胺的土壤中分离出菌株DC-1。通过严格的单因素和响应面分析，菌株DC-1在温度为32.89℃、pH为7.29、接种浓度为5.18%的优化条件下，表现出显著的87.06%的降解效率。通过液相色谱-质谱联用进一步推测，菌株DC-1对丁草胺的降解途径可能如下：丁草胺首先在双加氧酶的催化下进行脱氧反应，形成2-氯-N-(2,6-二乙基苯基)-N-甲基乙酰胺，随后进行N-去甲基化反应生成2-氯-N-(2,6-二乙基苯基)乙酰胺，最终转化为2,6-二乙基苯酚。此外，还进行了丁草胺污染土壤的生物修复实验。结果表明，菌株DC-1能在12天内降解土壤中99.23%的丁草胺（100mg·kg），且该菌能促进土壤蔗糖酶、纤维素酶和脲酶的活性。通过高通量测序得出，菌株DC-1能够影响土壤中某些细菌的相对丰度，使土壤中的微生物群落朝着更稳定、更有益的方向发展。因此，菌株DC-1因其强大的降解效果、良好的特性和生态修复能力，在丁草胺降解领域具有重要价值，凸显了其在丁草胺污染土壤生物修复中的潜在作用。
