耐药菌E.coli K12:RK2负荷下群感效应对好氧颗粒污泥稳定性的影响  

Effect of quorum sensing on the stability of aerobic granular sludge under drug resistant bacteria E.coli K12:RK2 load

作　　者：李文 房刈秋 薄琳 王尚 王景峰 LI Wen;FANG Yiqiu;BO Lin;WANG Shang;WANG Jingfeng(College of Marine Ecology and Environment,Shanghai Ocean University,Shanghai 300387,China;Institute of Environmental Medicine and Operational Medicine,Academy of Military Medicine,Academy of Military Sciences,Tianjin 300050,China)

机构地区：[1]上海海洋大学海洋生态与环境学院,上海300387 [2]军事科学院军事医学研究院环境医学与作业医学研究所,天津300050

出　　处：《环境工程学报》2023年第8期2736-2744,共9页Chinese Journal of Environmental Engineering

基　　金：天津市自然科学基金资助项目(19JCYBJC23800);国家自然科学基金资助项目(51678565);后勤科研重大项目(AWS18J004)。

摘　　要：研究了在携带RK2质粒的供体菌E.coli K12:RK2负荷下群体感应对好氧颗粒污泥稳定性的影响,同步运行了2个反应器(R1与R2),分别向反应器中添加E.coli K12和携带RK2质粒的供体菌E.coli K12:RK2,考察了其对系统污染物去除效率、污泥形态、EPS以及AHL含量的影响,分析并验证群体感应在维持好氧颗粒污泥稳定中的作用。结果表明,R1和R2中氨氮降解及污泥形态变化趋势一致,系统氨氮降解率下降,反应器中大颗粒污泥解体、絮状污泥增多。投菌作用下,R1和R2中胞外聚合物(EPS)含量显著降低(P<0.05),分别由(369.28±67.70)mg·g^(-1)和(372.22±86.53)mg·g^(-1)(以MLSS计)降至(242.47±20.25)mg·g^(-1)和(175.66±37.99)mg·g^(-1),且组间存在显著差异(P<0.05)。通过荧光定量PCR及荧光显微镜镜检发现RK2质粒在系统中发生接合转移。C4-HSL为系统的主要响应AHLs,在投菌后出现,R1和R2中含量分别为增加至(1.35±0.59)ng·g^(-1)和(2.30±0.52)ng·g^(-1),随后2个反应器中C4-HSL浓度均随着投菌进行逐渐降低;相关性分析结果表明,C4-HSL与EPS呈负相关关系;进一步研究发现,C4-HSL能够显著抑制污泥中EPS和胞外蛋白(PN)分泌。以上结果表明在携带RK2质粒的供体菌E.coli K12:RK2负荷下系统通过群感效应分子C4-HSL调控EPS含量来影响污泥形态,可为提高好氧颗粒污泥系统稳定性提供参考。The effect of quorum sensing on the stability of aerobic granular sludge under the load of E.coli K12:RK2 carrying RK2 plasmid was studied.Two reactors(R1 and R2)were run simultaneously,and E.coli K12 and donor bacteria E.coli K12:RK2 carrying RK2 plasmid were added to these two reactors,respectively,and their effects on the pollutant removal efficiency of the reactors,sludge morphology,EPS and AHL content were investigated.The role of quorum sensing in maintaining aerobic granular sludge stability was analyzed and verified.The results showed that the degradation trend of ammonia nitrogen was consistent with that of sludge morphology in R1 and R2,the degradation rate of ammonia nitrogen in the system decreased,and the large particle sludge was disintegrated and flocculent sludge increased in the reactor.Under the action of bacterialization,the content of extracellular polymers in R1 and R2 decreased significantly(P<0.05),from(369.28±67.70)mg·g^(−1)and(372.22±86.53)mg·g^(−1)(in terms of MLSS)to(242.47±20.25)mg·g^(−1)and(175.66±37.99)mg·g^(−1),respectively,and the significant differences occurred between groups(P<0.05).Fluorescence microscopy and qPCR showed that the conjugation transfer occurred for RK2 plasmids in the system.C4-HSLwas the main response of AHLs in this system.After germination,the contents of C4-HSL increased to(1.35±0.59)ng·g^(−1)and(2.30±0.52)ng·g^(−1),respectively,and then the concentration of C4-HSL gradually decreased with the propagation process.The correlation analysis results showed that C4-HSL had a negative correlation with EPS.Further studies have found that C4-HSL could significantly inhibit EPS and PN secretion in sludge.The above results show that under the donor bacteria E.coli K12:RK2 carrying the RK2 plasmid,the system regulated the EPS content to affect the sludge morphology by the group sensing effect molecule C4-HSL,which can provide a reference for improving the stability of aerobic granular sludge system.

关 键 词：好氧颗粒污泥 RK2质粒 EPS C4-HSL 稳定性 

分 类 号：X703[环境科学与工程—环境工程]