鞘氨醇单胞菌对微囊藻毒素-RR的降解作用与影响因素分析  

Biodegradation of Microcystin-RR by Sphingopyxis sp.and its influencing factors

作　　者：刘剀剡 丁勤[1] 袁梦玹 浦跃朴[1] Liu Kaiyan;Ding Qin;Yuan Mengxuan;Pu Yuepu(Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Southeast University, Nanjing 210009, China)

机构地区：[1]东南大学环境医学工程教育部重点实验室,南京210009

出　　处：《东南大学学报（自然科学版）》2021年第3期496-502,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金面上资助项目(81972997).

摘　　要：为探索微囊藻毒素微生物降解机制,研究了鞘氨醇单胞菌对微囊藻毒素-RR(MC-RR)的降解作用与影响因素.通过色谱及质谱方法阐明了鞘氨醇单胞菌对MC-RR的降解能力及途径,结合实时荧光定量聚合酶链式反应技术和酶活性分析探究了反应温度、营养基质及同类毒素(微囊藻毒素-LR,MC-LR)的影响及机制.结果表明:鞘氨醇单胞菌对MC-RR的最高降解速率达0.29 mg/(L·h),降解产物分别为C_(49)H_(77)N_(13)O_(13)、C_(32)H_(47)N_(4)O_(8)、C_(12)H_(19)N_(3)O_(6)和C_(20)H_(29)NO_(3);温度影响酶MlrA活性,在20~40℃范围内最适温度为30℃;提高磷质量浓度(100 mg/L K2HPO4)可刺激mlrA基因表达,使降解速率增加27.59%;提高碳质量浓度(100 mg/L葡萄糖)将抑制mlrA表达,使降解速率下降86.71%;MC-LR和MC-RR竞争性结合MlrA,使MC-RR降解速率下降4.44%.鞘氨醇单胞菌对MC-RR的降解能力较强,并受到温度、营养基质及MC-LR浓度的影响.To explore the microbial degradation mechanism of Microcystins,the degradation of Microcystin-RR(MC-RR)by Sphingopyxis sp.and its influencing factors were studied.The degradation ability and the pathway of MC-RR by Sphingopyxis sp.were clarified by chromatography and mass spectrometry.Combined with real-time fluorescent quantitative polymerase chain reaction technology and the analysis of enzyme activity,the effects and mechanisms of reaction temperature,nutrient matrix and similar toxins(Microcystin-LR,MC-LR)were investigated.The results show that the highest degradation rate of MC-RR is 0.29 mg/(L·h).The degradation products are C_(49)H_(77)N_(13)O_(13),C_(32)H_(47)N_(4)O_(8),C_(12)H_(19)N_(3)O_(6),and C_(20)H_(29)NO_(3).The temperature affects the activity of MlrA enzyme and the optimum temperature is 30℃at 20-40℃.Increasing phosphorus concentration(100 mg/L K2HPO4)can stimulate mlrA gene expression and increase the degradation rate by 27.59%.Increasing the carbon concentration(100 mg/L glucose)can inhibit mlrA gene expression and reduce the degradation rate by 86.71%.MC-LR and MC-RR are competitively combined with MlrA,the degradation rate of MC-RR is reduced by 4.44%.The Sphingopyxis sp.has strong ability to degrade MC-RR,thus it is affected by the temperature,the nutrient matrix and the MC-LR concentration.

关 键 词：微囊藻毒素-RR 鞘氨醇单胞菌 生物降解 影响因素 机制 

分 类 号：X522[环境科学与工程—环境工程]