ABSTRACT
This chapter provides a deeper insight into the functions of extracellular polymeric substances (EPS) in aerobic granulation. EPS are produced by microorganisms themselves during cultivation, which are advantageous in many respects for their survival in various circumstances. In the environmental engineering literature, there are contradictory reports on the composition of EPS in biogranules, especially the ratio of carbohydrates to proteins. The composition of EPS is related to the characteristics of the feed waste-water, for example EPS in anaerobic granules grown on protein-rich wastewater had high protein and DNA levels, whereas high polysaccharides content was found in anaerobic granules fed by other types of organic wastewaters. The EPS production seems to be positively related to the specific oxygen utilization rate of aerobic granules developed in sequencing batch reactors. EPS facilitate cell-to-cell interaction and further strengthen microbial structure through forming a polymeric matrix. The chapter shows that the essential roles of EPS in the formation and maintaining structural stability of aerobic granules.
