Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing, 210098, PR China; College of Environment, Hohai University, Nanjing, 210098, PR China.
Chemosphere. 2022 Feb;289:133218. doi: 10.1016/j.chemosphere.2021.133218. Epub 2021 Dec 7.
Pipe material and residual chlorine are key factors for the drinking water distribution system, and understanding the biofilm ecosystem is vital for water quality safeguard. The aim of our study was to determine the influence of pipe materials (ductile iron, steel, polyethylene) and chlorination on the biofilm structure and microbial community, as shown by the physicochemical properties, extracellular polymeric substances (EPS) structural characteristics, bacterial community composition, and functional traits. EPS spatial properties were studied based on a semi-quantitative confocal laser scanning microscope (CLSM) description. Regarding the impact of chlorination, residule chlorine (1.0 ± 0.3 mg L free chlorine) could inhibit the bacteria colonization, and initiate a potential response to external disinfectants revealed by the EPS spatial distribution changes and communities variation compared to unchlorinated system. Regarding the impact of pipe material, polyethylene (PE) biofilms displayed lower biomass, loose zoogloea structure, lower proteins and polysaccharides content, and poor microbial diversity in contrast to ductile iron and steel biofilms. Pipe material was the more possible driving factor of the biofilm community composition compared to the chlorination based on principal coordinates analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA). Actinobacteria was dominant in the PE biofilms (45.57%-83.32%), while Alphaproteobacteria (34.30%-73.22%) and Gammaproteobacteria (6.46%-36.82%) were the major classes in the steel and ductile iron biofilms. The genus Rhodococcus was predominant in the PE biofilms. Rhodococcus, Pseudomonas, and Sphingomonas seemed to have a better growth advantage in the chlorinated system and display a stronger disinfectant resistance. Functional sketch prediction indicated the potential impact of pipe material and chlorination on functional pathway abundnce, possible functional pathways associated with infectious disease included. This study provides insights into the impact of pipe material and chlorination on biofilm structure and microbial community and might help to develop monitoring or maintenance strategies to protect the biosafety of the drinking water.
管道材料和余氯是饮用水分配系统的关键因素，了解生物膜生态系统对于保障水质至关重要。本研究的目的是确定管道材料（球墨铸铁、钢、聚乙烯）和氯化作用对生物膜结构和微生物群落的影响，这些影响可通过理化性质、细胞外聚合物（EPS）结构特征、细菌群落组成和功能特征来体现。基于半定量共聚焦激光扫描显微镜（CLSM）描述研究了 EPS 的空间特性。关于氯化作用的影响，残留氯（游离氯 1.0 ± 0.3 mg/L）可以抑制细菌定植，并通过 EPS 空间分布变化和群落变化显示出对外界消毒剂的潜在反应，与未氯化系统相比。关于管道材料的影响，与球墨铸铁和钢生物膜相比，聚乙烯（PE）生物膜表现出较低的生物量、松散的菌胶团结构、较低的蛋白质和多糖含量以及较差的微生物多样性。基于主坐标分析（PCoA）和置换多元方差分析（PERMANOVA），与氯化作用相比，管道材料是生物膜群落组成的更可能的驱动因素。在 PE 生物膜中，放线菌占优势（45.57%-83.32%），而在钢和球墨铸铁生物膜中，α变形菌（34.30%-73.22%）和γ变形菌（6.46%-36.82%）是主要类群。PE 生物膜中优势属为红球菌属。在氯化系统中，节杆菌属、假单胞菌属和鞘氨醇单胞菌属似乎具有更好的生长优势，表现出更强的消毒剂抗性。功能草图预测表明，管道材料和氯化作用对功能途径丰度有潜在影响，可能与传染病相关的功能途径包括在内。本研究深入了解了管道材料和氯化作用对生物膜结构和微生物群落的影响，可能有助于制定监测或维护策略，以保护饮用水的生物安全性。
