Research progress on the regulation of signal molecule AI-2 during sludge granulation

Quorum sensing is a communication mechanism widely existing in microorganisms. Autoinducer-2 (AI-2), a kind of quorum sensing signaling molecule for interspecies communication, has received increasing attention for its role in regulating bacterial gene expression and aggregation. Granular sludge, as a kind of microbial aggregates, has been widely concerned and studied because of its advantages such as high microbial population, good settleability and high resistance to loads. A large number of studies have shown that AI-2 mediated quorum sensing plays an important role in the process of sludge granulation. This paper reviewed the formation of AI-2 signaling molecules and the mechanism of AI-2 mediated quorum sensing, the detection methods of AI-2, the influencing factors in the production of AI-2 and its distribution in granular sludge, summarized the regulatory role of AI-2 in the process of granulation, and finally provided an outlook of the research of AI-2 mediated quorum sensing in granular sludge. The aim is to provide theoretical references for the in-depth understanding of the regulation effect of quorum sensing on sludge granulation as well as for promoting the engineering application of sludge granulation. © 2024 Chemical Industry Press Co., Ltd.. All rights reserved.