CAJ | 학술논문

有机磷农药是目前环境中残留量最多的农药之一，对其残留量的检测及降解机制的研究对于环境污染及生态修复具有重要意义。微生物传感器由生物学元件与换能器构成，因具有成本低廉、易于微型化及选择性高等特点而被广泛应用于各种生化物质的分析和检测。本文从长期受农药污染的土壤中分离出4株能以甲基对硫磷为碳源生长的菌株，根据形态特征和16S rRNA基因序列同源性分析，对4株降解菌进行鉴定，利用高效液相色谱测定降解率，选取降解率最高的1株菌进行降解机制研究，以期将其应用于测定环境中甲基对硫磷残留的电位型微生物传感器的构建。结果表明，在甲基对硫磷初始浓度50 mg·L-1、30℃、pH 7.0的培养条件下培养7 d，4株菌对甲基对硫磷的降解率均在78%以上，其中1株菌的降解效率可达100%。16S rRNA基因序列测定表明，该菌株属于克雷伯氏菌属，命名为Klebsiella sp. MP-6。利用液相色谱-质谱联用对其降解产物的研究表明，菌株MP-6水解甲基对硫磷主要产生二甲基硫代磷酸（dimethyl thiophosphoric acid, DMTP）和对硝基苯酚（p-nitrophenol, PNP），极少部分PNP通过产生4-硝基邻苯二酚（4-nitrocatechol,4-NC）和1,2,4-苯三酚（1,2,4-BT）进一步代谢。结果表明，基于测定中间产物对硝基苯酚（p-nitro-phenol, PNP）的电位响应信号，该菌株适用于构建测定海水及土壤等环境中有机磷农药的微生物传感器。
유궤린농약시목전배경중잔류량최다적농약지일，대기잔류량적검측급강해궤제적연구대우배경오염급생태수복구유중요의의。미생물전감기유생물학원건여환능기구성，인구유성본저렴、역우미형화급선택성고등특점이피엄범응용우각충생화물질적분석화검측。본문종장기수농약오염적토양중분리출4주능이갑기대류린위탄원생장적균주，근거형태특정화16S rRNA기인서렬동원성분석，대4주강해균진행감정，이용고효액상색보측정강해솔，선취강해솔최고적1주균진행강해궤제연구，이기장기응용우측정배경중갑기대류린잔류적전위형미생물전감기적구건。결과표명，재갑기대류린초시농도50 mg·L-1、30℃、pH 7.0적배양조건하배양7 d，4주균대갑기대류린적강해솔균재78%이상，기중1주균적강해효솔가체100%。16S rRNA기인서렬측정표명，해균주속우극뢰백씨균속，명명위Klebsiella sp. MP-6。이용액상색보-질보련용대기강해산물적연구표명，균주MP-6수해갑기대류린주요산생이갑기류대린산（dimethyl thiophosphoric acid, DMTP）화대초기분분（p-nitrophenol, PNP），겁소부분PNP통과산생4-초기린분이분（4-nitrocatechol,4-NC）화1,2,4-분삼분（1,2,4-BT）진일보대사。결과표명，기우측정중간산물대초기분분（p-nitro-phenol, PNP）적전위향응신호，해균주괄용우구건측정해수급토양등배경중유궤린농약적미생물전감기。
Methyl parathion(MP), a kind of typical organophosphates pesticides(OPs), is widely used as agricultural insecticides. However, due to their neurotoxic effects on humans, the elimination of OPs has become increasingly important. Microbial sensors are consisted of bio-logical components and transducers. Owing to their attractive advantages including low cost, easy of miniaturization and excellent selectivity, they have been widely used for environmental analysis. In this paper, four novel bacterial strains capable of utilizing methyl parathion as the sole carbon source were isolated from pesticide contaminated soils. These four isolates were identified based on morphological characteristics and 16S rRNA gene sequences analysis, and their capability of degrading methyl parathion were investigated by high performance liquid chromatography. The highest degrading efficiency strain was selected for further study of degrading mechanism. The results indicated that degradation rate of these four strains were all over 78%after incubation at 30 ℃, pH 7.0 for 7 d with the original concentration of methyl parathion 50 mg·L-1. The highest degradation rate was up to 100%. 16S rRNA gene sequences indicated that strain MP-6 was affiliated into the genus klebsiella. The LC-MS results indicated that methyl parathion was hydrolyzed to dimethyl thiophosphoric acid and p-nitrophenol by MP-6. A little of p-nitrophenol molecules could be further metabolized to 4-nitrocatechol and 1, 2, 4-benzenetrio. The results indicated that based on detecting the potential signal of intermediate product p-nitrophenol, the strain MP-6 could be used to construct microbial sen-sors for determination of organophosphorus pesticides in environment.