稻田除草剂二氯喹啉酸降解菌15^(#)的分离、鉴定及降解特性

Isolation, identification and degradation characteristics of paddy field herbicide quinclorac degrading bacteria 15

【背景】二氯喹啉酸(Quinclorac,QNC)是一种高选择性、激素类、低毒性除草剂,主要用于防治稻田稗草,持效期长,易于在土壤中积累而影响后茬作物的生长发育,而且环境中残留的QNC可对动物生长发育产生不良影响,并影响微生物的群落结构和丰度。【目的】从稻田土壤中分离筛选出一株可降解除草剂QNC的菌株,鉴定并明确其降解特性。【方法】通过形态学、生理生化试验、磷脂脂肪酸(Phospholipid Fatty Acid,PLFA)微生物鉴定、16S rRNA基因测序及分析鉴定菌株。通过单因素实验探究菌株的降解特性。【结果】筛选得到一株编号为15^(#)的QNC降解菌,被鉴定为无色杆菌属菌株(Achromobactersp.)。降解特性研究结果表明,菌株15^(#)的最佳培养条件为:30℃、pH为6.0、初始QNC浓度为100 mg/L、接种量为7%、添加质量分数为0.1%的酵母浸粉、氮源为蛋白胨,在此条件下培养21d后QNC的降解率可达43.0%。【结论】筛选到降解QNC新菌株并为该菌株的进一步研究提供理论基础。

[Background] Quinclorac(QNC) is a highly selective, hormonal, and low-toxic herbicide. It is mainly used to control barnyard grass in rice fields with a long duration. And the growth and development of subsequent crops are easily affected by QNC accumulated in the soil. In addition, the growth and development of animals will be affected by the residual QNC in the environment, as well as the community structure and the abundance of microorganisms also will be affect. [Objective] To isolate and screen a strain of degrading the herbicide QNC from the paddy soil, and determine its degradation-characteristics. [Methods] The strain was identified by morphological, physiological and biochemical tests, phospholipid fatty acid(PLFA) microbial identification, 16 S rRNA gene sequence. The degradation characteristics of strains with single factor analysis was carried out. [Results] The QNC-degradation strain numbered 15;was screened and identified as Achromobacter sp. The results of the research on the degradation characteristics show that the optimum conditions for strain 15;were 30 ℃, pH 6.0, initial QNC concentration 100 mg/L, inoculation amount 7%, and added mass fraction 0.1% of yeast extract powder and nitrogen source are peptone. Under the conditions, the degradation rate of QNC could reach 43.0% after cultured 21 d. [Conclusion] A new strain was screened for microbial degradation of QNC and provided a theoretical basis for further research on this strain.