Ahls Triggers the Promotion of Biofilm Formation in the Hydrogen-Based Membrane Biofilm Reactor

Abstract

The growth rate of autotrophic microorganisms and biofilm thickness are important limitations in hydrogen-based membrane biofilm reactor (H2-MBfR). The quorum sensing (QS) system, particularly mediated by AHLs signals, plays a crucial role in controlling biofilm behavior. This study investigated the impact of QS signaling molecules mediated by AHLs on the stability and development of biofilm maturation in H2-MBfR. The results revealed a strong correlation between EPS content and C4-HSL, C8-HSL, C14-HSL, and 3-oxo-C14-HSL, indicating that these signal types predominantly regulate biofilm behavior. During early stages of biofilm formation, C4-HSL and C14-HSL were prominently detected, promoting adhesion, while 3-oxo-C14-HSL inhibited EPS secretion. In the mature stage, C8-HSL enhanced structural stability Analysis of community structure and metagenome data showed that Rhodopseudomonas palustris and Vibrio parahaemolyticus serotype O3:K6 played key roles in nitrogen transformation and AHLs production. Additionally Enterobacter sp., dominated in AI-2-QS regulatory system worked together with AHLs-QS system during biofilm formation.

Keywords: Hydrogen-based membrane biofilm reactor (H2-MBfR), Acyl-homoserine lactones (AHLs), Quorum sensing (QS), Biofilm modulation.