Program

Oral Sessions

Day 3, May 17（Thu.）　17:55-18:15　Room B (Seiun 1)

3B-O3-M-1755　　PDF

Detection of bacterial signaling molecules in activated sludge by LC-HRMS

(¹Univ. Tokyo, ²Univ. Tokyo, ³AIT)
^oTomohiro Tobino¹, Daisuke Yagi², Fumiyuki Nakajima², Kazuo Yamamoto^1,3

Numerous bacteria are known to regulate their gene expression in accordance with their population density through a system called quorum sensing, which utilizes small signaling molecules produced, released, and received by bacterial cells. Quorum sensing is suggested to be involved in activated sludge community applied in biological wastewater treatment systems and therefore can be an important factor that determines process performance. Recently engineering quorum sensing in membrane bioreactor (MBR) has shown its potential to mitigate membrane fouling, a major drawback of MBR technologies. Few studies, however, measured the concentrations of signaling molecules in their system and the role of signaling molecules remains to be unraveled. In this study, we operated lab-scale MBRs treating municipal wastewater and monitored concentrations of signaling molecules in the MBRs by using LC-HRMS. N-acyl homoserine lactones (AHL) were selected as target signaling molecules, recovered by solid phase extraction from 40 ml of samples, and analyzed by LC-HRMS (Q-Exactive Focus, Thermo Fisher Scientific). All of the 10 targeted AHL species were detected at 10⁰-10² ng/L, indicating the presence of diverse AHLs in the activated sludge. Of these, C8-HSL concentration in permeate had tight correlation with membrane fouling (i.e. transmembrane pressure development) during, but not always, certain filtration cycles.