Analysis of characteristics extracellular polymeric substances extracted from aerobic granular sludge by different methods

The characteristics of the extracellular polymeric substances (EPS) extracted with eight different extraction protocols from two different types of aerobic granular sludge were studied. The efficiency of four single methods including NaOH, sonication, heating and cationic exchange resin (CER) and four their combination methods was compared with each other. The EPS of the aerobic granular sludge investigated are predominantly composed of polysaccharides, proteins, and humic-like substances. The nucleic acid content of the EPS extracted show that the extraction whether induce abnormal cellular lysis or not. The EPS content in each biochemical compound varies depending on the sludge type and extraction technique used. Combination methods can provide more EPS than every single method, which suggests that there is a complementary and mutual promoting relationship between each method.