目的 观察使用三氯异氰尿酸消毒游泳场所时主要消毒副产物水平。方法 通过现场采样和化学分析方法，对昆山市区1家使用三氯异氰尿酸消毒的游泳场所水中消毒副产物进行监测。结果 经三氯异氰尿酸消毒的游泳池水pH值、游离性余氯、化合性余氯和尿素的合格率分别为49.1%、97.2%、54.7%和97.2%。消毒后的游泳池水浑浊度、游离性余氯、化合性余氯、总余氯指标值均高于自来水。消毒后室内外泳池水中11种消毒副产物均可检出，其中三氯甲烷、三氯乙酸和二氯乙酸浓度最高。结论 三氯异氰尿酸在满足消毒效果的前提下，三氯甲烷浓度处于较低水平，应当注意高浓度卤乙酸可能带来的风险。

Cyanuric acid was likely present on prebiotic Earth, may have been a component of early genetic materials, and is synthesized industrially today on a scale of more than one hundred million pounds per year in the United States. In light of this, it is not surprising that some bacteria and fungi have a metabolic pathway that sequentially hydrolyzes cyanuric acid and its metabolites to release the nitrogen atoms as ammonia to support growth. The initial reaction that opens the s-triazine ring is catalyzed by the unusual enzyme cyanuric acid hydrolase. This enzyme is in a rare protein family that consists of only cyanuric acid hydrolase (CAH) and barbiturase, with barbiturase participating in pyrimidine catabolism by some actinobacterial species. The X-ray structures of two cyanuric acid hydrolase proteins show that this family has a unique protein fold. Phylogenetic, bioinformatic, enzymological, and genetic studies are consistent with the idea that CAH has an ancient protein fold that was rare in microbial populations but is currently becoming more widespread in microbial populations in the wake of anthropogenic synthesis of cyanuric acid and other s-triazine compounds that are metabolized via a cyanuric acid intermediate. The need for the removal of cyanuric acid from swimming pools and spas, where it is used as a disinfectant stabilizer, can potentially be met using an enzyme filtration system. A stable thermophilic cyanuric acid hydrolase from Moorella thermoacetica is being tested for this purpose.Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Di- and trichloroisocyanuric acids are widely used as water disinfection agents, but cyanuric acid accumulates with repeated additions and must be removed to maintain free hypochlorite for disinfection. This study describes the development of methods for using a cyanuric acid-degrading enzyme contained within nonliving cells that were encapsulated within a porous silica matrix. Initially, three different bacterial cyanuric acid hydrolases were compared: TrzD from Acidovorax citrulli strain 12227, AtzD from Pseudomonas sp. strain ADP, and CAH from Moorella thermoacetica ATCC 39073. Each enzyme was expressed recombinantly in Escherichia coli and tested for cyanuric acid hydrolase activity using freely suspended or encapsulated cell formats. Cyanuric acid hydrolase activities differed by only a 2-fold range when comparing across the different enzymes with a given format. A practical water filtration system is most likely to be used with nonviable cells, and all cells were rendered nonviable by heat treatment at 70°C for 1 h. Only the CAH enzyme from the thermophile M. thermoacetica retained significant activity under those conditions, and so it was tested in a flowthrough system simulating a bioreactive pool filter. Starting with a cyanuric acid concentration of 10,000 μM, more than 70% of the cyanuric acid was degraded in 24 h, it was completely removed in 72 h, and a respike of 10,000 μM cyanuric acid a week later showed identical biodegradation kinetics. An experiment conducted with water obtained from municipal swimming pools showed the efficacy of the process, although cyanuric acid degradation rates decreased by 50% in the presence of 4.5 ppm hypochlorite. In total, these experiments demonstrated significant robustness of cyanuric acid hydrolase and the silica bead materials in remediation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.