Influence of Organic Loading Rate and Feast Regime on Alginate-Like EPS Production from Aerobic Granular Sludge

This study investigated the influence of organic loading rate (OLR) and feeding regime on the production of alginate-like exopolysaccharides (ALEs) from aerobic granular sludge treating citrus-processing wastewater. Two granular sequencing batch reactors were operated under anaerobic and aerobic feast conditions at increasing OLRs (1-2.5 kgCOD/m³d). Results showed that OLR and feeding regime significantly affected extracellular polymeric substances (EPS) yield and composition. Anaerobic feast conditions promoted higher structural EPS fractions, while aerobic conditions favored higher total EPS production. The results highlight the potential of aerobic granular sludge systems for the simultaneous treatment of agro-industrial wastewater and recovery of valuable biopolymers.