Giri Krishna, Pandey Shailseh, Kumar Rajesh, Rai J P N
Rain Forest Research Institute, Jorhat, Assam, 785 001, India.
G. B. Pant University of Agriculture and Technology, Pantnagar, 263145, India.
3 Biotech. 2016 Dec;6(2):190. doi: 10.1007/s13205-016-0505-8. Epub 2016 Sep 2.
A gram-negative, rod-shaped, isoproturon (IPU) utilizing bacterium was isolated from herbicide-applied wheat fields of Tarai agro-ecosystem, Pantnagar. The phylogenetic sequence analysis based on 16S rRNA sequence revealed that the isolate could be a distinct species within the genus Pseudomonas. The isolate was a close relative of Pseudoxanthomonas japonensis (95 % similarity) and designated as K2. The bacterial isolate showed positive reaction for oxidase, catalase, and 20 carbohydrates using KB009 Part A and B HiCarbohydrate™ Kit. Degradation experiments were conducted using 200 mg l initial IPU as a source of carbon at different pH and temperatures. Maximum IPU degradation by K2 was observed at pH 7.0 and 30 °C, while least degradation at 6.5 pH and 25 °C. Addition of dextrose along with IPU as an auxiliary carbon source increased IPU degradation by 4.72 %, as compared to the IPU degradation without dextrose under optimum conditions. 4-isopropylaniline was detected as a degradation by-product in the medium. The present study demonstrated the IPU metabolizing capacity of a novel bacterial isolate K2 that can be a better choice for the remediation of IPU-contaminated sites.
从潘特纳加尔特莱农业生态系统中施用除草剂的小麦田中分离出一株利用异丙隆（IPU）的革兰氏阴性杆状细菌。基于16S rRNA序列的系统发育序列分析表明，该分离株可能是假单胞菌属内的一个独特物种。该分离株是日本假黄单胞菌的近亲（相似度为95%），并被命名为K2。使用KB009 A部分和B部分HiCarbohydrate™试剂盒对该细菌分离株进行氧化酶、过氧化氢酶和20种碳水化合物的检测，结果呈阳性。以200 mg l初始IPU作为碳源，在不同pH值和温度下进行降解实验。K2在pH 7.0和30°C时对IPU的降解量最大，而在pH 6.5和25°C时降解量最少。与在最佳条件下不添加葡萄糖的IPU降解相比，添加葡萄糖作为辅助碳源可使IPU降解量增加4.72%。在培养基中检测到4-异丙基苯胺作为降解副产物。本研究证明了新型细菌分离株K2具有代谢IPU的能力，它可能是修复受IPU污染场地的更好选择。
