Determining the mechanism for biomass segregation between granules and flocs in anammox granular system from the prospective of EPS

Harnessing the Potential of Extracellular Polymeric Substances in Enhancing ANAMMOX Processes: Mechanisms, Strategies, and Perspectives

“…This suggests that proteins play a more important role in the structural stability and functional activity of ANAMMOX biofilms/granules when compared to polysaccharides. In addition, the proteins in ANAMMOX sludge have a looser secondary structure and also have more hydrophobic functional groups, which were thought to be the key to the aggregation of ANAMMOX sludge [17]. The monosaccharide composition of ANAMMOX EPS polysaccharides usually includes glucose, galactose, mannose, glucosamine, and glucuronic acids [39].…”

“…More importantly, EPSs also exist as skeletons of microbial aggregates. The polysaccharide branch structure and glycoprotein play a vital role in maintaining the structure of ANAM-MOX granules [17]. Recently, integrated genomic and glycomic analyses revealed that ANAMMOX genera contain unique gene clusters for synthesizing novel polysaccharides and glycoproteins that are absent in other bacteria [41].…”

“…In recent years, harnessing the potential of extracellular polymeric substances (EPSs) to improve ANAMMOX performance has gained growing interest. An EPS is a complex mixture of high-molecular-weight secretions produced by microorganisms, mainly composed of polysaccharides, proteins, nucleic acids, and lipids [17]. EPSs play essential roles in the formation and function of biofilms and granular sludge, two common forms of microbial aggregates used in wastewater treatment [18].…”

“…ANAMMOX bacteria can naturally excrete large amounts of EPSs during cultivation, which contributes to their aggregation, adhesion, and stress resistance [19]. Studies have shown that supplementing ANAMMOX reactors with extracted EPSs or EPS-producing bacteria can significantly promote the growth, activity, and stability of ANAMMOX microorganisms under various conditions [17,[19][20][21]. The mechanisms involve the provision of structural support, a protective barrier, sorption sites, electron shuttles (ESs), signaling molecules, and nutrients from EPSs to ANAMMOX bacteria and their symbiotic partners [22][23][24].…”