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Abstract: It is important to obtain a considerable quantity of DNA from oligotrophic environments such as a drinking water distribution system (DWDS) to study microbial communities by molecular biotechnology, and DNA yield is always one of the biggest problems when performing metagenomic sequencing on drinking water samples. To obtain as many microbes as possible, ultrasound has been widely used in cell detachment, but studies on the optimal ultrasonic parameters for biofilm in DWDS have rarely been seen. The effects of three ultrasonic parameters, including power, duration, and the number of ultrasound treatments (USTs) on the selected monoculture bacteria (Pelomonas sp.) biofilm were studied first. Then the optimal values of each ultrasonic parameter were initially determined. Based on these values, three levels of each ultrasonic parameter were selected, and then an orthogonal experiment was conducted to further study drinking water biofilm, and finally the optimal ultrasonic parameters for the effective separation of biofilm cells in DWDS were determined. The results showed that the optimal ultrasonic power, duration, and the number of USTs are 13 W, 1 min, and 15, respectively. A 20-min interval is needed between two USTs. The present optimal UST, which does not lose DNA quality, can increase the amount of extractable DNA by at least 4.78 times compared to samples without UST. This study provides a pretreatment methodology for extracting more and reliable DNA from biofilm in DWDS, and can better solve the problem of DNA collection in oligotrophic environments.

This journal manuscript by Pend and others describes a microbial study of DNA sampling from drinking water distribution pipes, and offers new insights on operational parameters of ultrasound techniques for reliable DNA harvesting. Using experiments, cPCR and other molecular biological methods, the authors conducted a statistical analysis of the results for optimal ultrasonic parameters when the biological sampling technique is used for sufficient extraction of the samples without compromising of the HPC sample integrity. The results are important to sampling and biological monitoring of drinking water systems, especially in compliance of biological standards in water systems. This can add to the understanding and contribute to standard setting. Thus, I think the presented research is valuable and of interests to journal's readers and to the scientific community in general.

促进饮用水供水管道生物膜脱落的超声处理参数优化

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