In the biomonitoring using environmental DNA (eDNA) analysis, the suppression of eDNA degradation has been an important issue to estimate accurately the presence of target species and their eDNA concentrations. A recently proposed eDNA preservation technique requires only the addition of benzalkonium chloride (BAC) to water samples and has been used for various studies as an alternative solution to on-site filtration. However, BAC remaining in filters may adsorb to and inhibit the function of the enzyme used to extract eDNA from filters. In this study, we tested whether eDNA yield is affected by BAC addition immediately before filtration and demonstrated that the BAC in water remaining in filters decreased the eDNA yield significantly. We found that simple pre-centrifugation is effective for removing the remaining water from the filters to prevent the eDNA yield reduction due to the use of BAC. This is the most important finding in the present study. Appropriate eDNA extraction techniques are needed when BAC is used to secure eDNA yields and expand the application of eDNA analysis for biomonitoring.

在使用环境 DNA (eDNA) 分析的生物监测中，抑制 eDNA 降解一直是准确估计目标物种的存在及其 eDNA 浓度的重要问题。最近提出的 eDNA 保存技术只需要向水样中添加苯扎氯铵 (BAC)，并已被用于各种研究，作为现场过滤的替代解决方案。然而，残留在过滤器中的 BAC 可能会吸附并抑制用于从过滤器中提取 eDNA 的酶的功能。在这项研究中，我们测试了 eDNA 产量是否会在过滤前立即添加 BAC 受到影响，并证明过滤器中残留的水中的 BAC 显着降低了 eDNA 产量。我们发现简单的预离心可有效去除过滤器中剩余的水，以防止因使用 BAC 而导致 eDNA 产量降低。这是本研究中最重要的发现。当 BAC 用于确保 eDNA 产量并扩大 eDNA 分析在生物监测中的应用时，需要适当的 eDNA 提取技术。