采用富集培养的方法从农药厂污泥和长期受乙草胺污染的土壤中分离到1株能以乙草胺为氮源生长的细菌命名为A-3,经16S rRNA鉴定,菌株A-3属于粘着剑菌属(Ensifer adhaerens).研究结果表明,菌株A-3能以乙草胺作为唯一氮源生长并高效降解乙草胺.在含10 mg/L乙草胺的无机盐培养基中培养10 d后,菌株A-3对乙草胺的降解率为33.6%.培养基的组成可影响菌株A-3的生长和对乙草胺的降解.碳源种类不同,菌株A-3的生长能力和降解能力也不同,其中在以蔗糖为碳源时A-3的生长能力最强,其D600值为0.55,而降解率仅有9.4%;而在以葡萄糖为碳源时菌株A-3的生长量D600只有0.3,但A-3对乙草胺的降解能力最强,其降解率为29.2%.培养基中的盐浓度也影响菌株的生长和对乙草胺的降解,在NaCl浓度为0.5%时,A-3生长能力和降解能力最高,降解率可达35%;但当NaCl浓度达到7%时,A-3的生长受抑制,且对乙草胺的降解率仅有2.6%.研究结果表明,菌株A-3能高效降解乙草胺,而且菌株的生长和降解过程受环境介质的影响,可以通过改变培养基的成分来调控菌株A-3对乙草胺的降解.
The strain A-3 which could use acetochlor as the sole nitrogen source was isolated from soils contaminated with acetochlor and the sludge of pesticide factory by enrichment culture.The strain was identified as Ensifer adhaerens according to the results of morphology,physiology,and the phylogenetical analyses of 16S rRNA sequence.It was observed that the degradation rate of acetochlor by strain A-3 was 33.6% after 10 days culture at the concentration of 10 mg/L.The composition of the culture could affect the growth of A-3 and the degradation of acetochlor.The growth and degradation ability of strain A-3 were different with the different carbon sources.The strain had the strangest growth capability with the D600 value of 0.55,but the degradation rate was only 9.4% when using sucrose as carbon source.However,the strain A-3 had the highest degradation rate up to 29.2%,although the D600 value was only 0.3 when using glucose as carbon source.When the NaCl concentration was 0.5%,the strain A-3 grew best and had the highest degradation rate of 35%,but when the NaCl concentration was higher than 7%,the growth of A-3 was inhibited and the degradation rate was reduced to 2.6%.The results showed that the strain A-3 could degrade acetochlor effectively and the growth and degradation process was affected by environmental media,and the degradation of acetochlor could be controlled by changing the composition of the culture.