Biofilm is a microbial population which live in a self-produced extracellular polymeric matrix by attaching to surfaces. Biofilms consist of different different types of organisms such as bacteria, fungi, protozoa, etc. Many biofilms that develop in nature consist of more than one type of organism. Biofilms protect bacteria from adverse conditions such as temperature fluctuation and disinfectants. The aim of this study was to determine the effective elimination strategies for combating biofilm and planktonic bacteria in cooling tower model system using different decontamination / disinfection techniques. In this study, 14 week-old biofilms were treated with temperatures of 4 °C, 65 °C; pH of 3, 11; 2 and 10 mg/l chlorine, 2 and 10 mg/l monochloramine; hypotonic salt (0.01% NaCl) and hypertonic salt (3% NaCl) solution. For enumeration, number of aerobic heterotrophic bacteria was determined by conventional culture method, number of live bacteria was determined by LIVE/DEAD viability kit, CTC-DAPI and Alamar blue staining methods. Temperature of 65 °C, pH of 3, 10 mg/l monochloramine and hypertonic salt solution were the most effective parameters for decontamination of biofilm and planktonic bacteria. Biofilm bacteria in the circulating water system were significantly more resistant than planktonic bacteria against stress factors. When the numbers of epifluorescence microscopy and conventional culture technique were compared, significantly higher number of live bacteria were detected using epifluorescence microscopy. Bacteria enter the viable but non-culturable phase by loosing their culturability under stress conditions. For this reason, the conventional culture method should be supported by different techniques to get more realistic numbers.

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冷却塔模型系统中各种应力因素对生物膜和浮游细菌的影响研究

生物膜是一种微生物种群，它们通过附着在表面上而生活在自产的细胞外聚合物基质中。生物膜由不同类型的生物组成，例如细菌、真菌、原生动物等。自然界中形成的许多生物膜由不止一种类型的生物组成。生物膜可保护细菌免受温度波动和消毒剂等不利条件的影响。本研究的目的是确定使用不同净化/消毒技术对抗冷却塔模型系统中生物膜和浮游细菌的有效消除策略。在这项研究中，14 周龄的生物膜在 4 °C、65 °C 的温度下进行处理；pH值为3、11；2 和 10 毫克/升氯，2 和 10 毫克/升一氯胺；低渗盐 (0.01% NaCl) 和高渗盐 (3% NaCl) 溶液。对于枚举，需氧异养菌数采用常规培养法测定，活菌数采用LIVE/DEAD活力试剂盒、CTC-DAPI和Alamar blue染色法测定。65 °C 的温度、3 的 pH 值、10 mg/l 的一氯胺和高渗盐溶液是生物膜和浮游细菌净化的最有效参数。循环水系统中的生物膜细菌对压力因素的抵抗力明显高于浮游细菌。当比较落射荧光显微镜和传统培养技术的数量时，使用落射荧光显微镜检测到的活细菌数量明显更高。细菌通过在压力条件下失去其可培养性而进入有活力但不可培养的阶段。为此原因，