AcknowledgementsThis study was financially supported by the National Hi-Tech Research and Development Program of China (863) (No. 2011AA060906), National Natural Science Foundation of China (No. 51178261), the Key project of Science and Technology Commission of Shanghai Municipality (Nos. 12231202101, 14DZ1207306).
Appendix A. Supplementary data
Supplementary data 1.
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Polyhydroxyalkanoate (PHA); Extracellular polysaccharide (EPS); Aerobic granules; PHA recovery
Discussions about the role of the EPS in PHA recovery from aerobic granules or any other mixed culture are lacking in the literatures. Earlier findings show that Sunitinib Malate the protein content in the EPS exhibited 8-fold increases during the transition from floccular to granular sludge (Zhu et al., 2012). This increase strengthens the structure of the aerobic granules and against toxic attacks.
Conventionally, PHA recovery from microorganisms first requires cell digestion. Many solvents and oxidizing agents have been explored for cell digestion. The most common cell digesting agent is sodium hypochlorite (Hahn et al., 1994). Other solvents, such as acetone, and sodium dodecyl sulfate (SDS), have occasionally been used (Duque et al., 2014). In the subsequent PHA recovery step, chloroform has primarily been used to dissolve PHA (Heinrich et al., 2012). The combination of cell digestion and PHA recovery methods have produced yields over 60% with purities varying between 85% and 99% for common mixed cultures (Chen et al., 2013 and Serafim et al., 2008). However, none of these PHA recovery methods have been considered for aerobic granules and much less for EPS-coated aerobic granules. Thus, there is a strong need to investigate the effects of EPS removal on PHA yield.