The production of wastewater from human activities is inevitable. As a consequence, wastewater treatment plants have an increasingly important role, contributing to sustainably close the water cycle. Aerobic granular sludge is a compact, robust and low energy-consuming wastewater treatment system. Extracellular polymeric substances, representing around 90% of aerobic granules dry weight, have shown to be key not only for the granule’s formation and structural stability but also potentially to protect the microbial community from environmental stresses. Currently, a paradigm shift is taking place, leading to an increased need to turn wastewater treatment plants more sustainable, with a range of opportunities for resource recovery, integrating them into the circular economy concept. Unravelling the effect of the extraction procedures on product characteristics and yields, the EPS protective role under stress conditions as well as the link between the AGS microbiome and EPS production could benefit the recovery and valorization of this bioproduct, as an asset towards a circular economy.