Alginate-like exopolysaccharides in aerobic granular sludge: a review

Abstract

Granular instability and a long granulation start-up period are significant challenges in implementing a full-scale aerobic granular sludge system. Identifying extracellular polymeric substances (EPS) components and their interactions is the key determinant to overcoming these challenges. Because of the high complexity of EPS, alginate-like exopolysaccharides (ALE) can be used as a model component as it is identified as the principal constituent of EPS. The feasibility of extracting ALE in aerobic granular sludge has been intensively studied; however, ALE characterization is still ongoing, and its role in EPS are still overlooked up until now. Moreover, research on its characteristics has demonstrated ALE to be a potential resource recovery. This review highlighted ALE's physical and chemical characteristics, factors influencing ALE composition and content in aerobic granular sludge, and ALE as possible resource recovery. This review also discusses the correlation between ALE, EPS, and granulation processes in aerobic granular sludge systems.