Development of simple, rapid and low-cost onsite simultaneous measurement technique of indicator bacteria based on fluorescence probes

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K21979
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 22:Civil engineering and related fields
• Research Institution: Hokkaido University
• Principal Investigator: Satoh Hisashi 北海道大学, 工学研究院, 教授 (80326636)
• Co-Investigator(Kenkyū-buntansha): 羽深 昭 北海道大学, 工学研究院, 助教 (30735353) ; 齋藤 伸吾 埼玉大学, 理工学研究科, 教授 (60343018)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: センサ

Outline of Final Research Achievements

We developed a simple, rapid, and low-cost simultaneous on-site indicator bacteria measurement technique using fluorescent probes. A sample with 40 cfu/L of E. coli could be detected in about 7 hours, and a sample with 4 cfu/L in about 13 hours. The operation is extremely simple: even with untreated sewage, the sample water is placed in a liquid medium or agar medium without any pretreatment, and the fluorescence intensity is automatically measured once every 10 minutes using a microplate reader set at 37°C. Since the number of coliform bacteria can be measured in about three hours for normal treated sewage water, the number of coliform bacteria can be analyzed with high frequency in both time and space, and deterioration of treatment efficiency can be quickly identified. Since the measurement medium is about 0.02 mL, the cost per sample is about 2 Japanese yen.

Free Research Field

水環境工学

Academic Significance and Societal Importance of the Research Achievements

極めて簡易にオンサイトで大腸菌を計測できるようになり、特に熟練の技術者がおらず分析にコストをかけられない開発途上国の人の健康と環境を守ることができる。現在は指標細菌数を計測するまでに約24時間かかるが、本法ではわずか3時間で計測が終了するので、指標細菌数が基準値を超えた場合に迅速に対応することが可能となる。現在世界中で広く用いられている計測キットのコストは1サンプル当たり約1300円であるが、本法は1サンプル2円であるので、開発途上国でも問題なく使用できる。一度に96サンプル測定できるので高頻度で指標細菌の経時変化を追う、広範囲の指標細菌の分布を計測する、などが可能となる。