Hydraulic Resistance and Macromolecular Structure of Aerobic and Anaerobic Mixed-Culture Extracellular Polymeric Substances Gel Layers: Opportunities and Challenges

Soluble Extracellular Polymeric Substances (sEPS) are a mixture of microbial soluble polymers produced during aerobic or anaerobic treatment wastewater. Gel layers mainly consisting sEPS usually present in the fouling membrane bioreactors (MBRs) and dynamic membranes (DMs) (DMBRs), their properties have not been thoroughly investigated over years. In this study, fractions recovered from reactors were analyzed tested to build-up EPS gel on 0.2 µm pore size polycarbonate carrier. Dead-end filtration experiments showed that layers, which low polysaccharide:protein (PS:PN) ratio, had lower hydraulic resistance than show high PS:PN ratio. Optical Coherence Tomography (OCT) Confocal Laser Scanning Microscopy (CLSM) analyses highlighted both similar thicknesses 3D structural organizations. Fluorescent staining organics biovolume analysis revealed for (low PS:PN), abundance proteins appears destabilize polysaccharide network increasing water permeability through layer. Additionally, polysaccharides α-linked type, contributing more open crosslinked within layer, resulting measured. The characteristics observed study mixed cultures interest possible future application those as reactors.