Acetone is a polar solvent with an electronegative carbonyl group. This carbonyl group disrupts hydrogen bonds in GW788388 and causes protein denaturation. Therefore, when acetone was applied to the aerobic granules, it reacted with cellular proteins and the EPS. As a result, the EPS proteins were denatured and removed. However, acetone was only able to disrupt the tertiary bonds of the protein; the primary bonds of the protein remained intact (Simpson and Beynon, 2009). This could be a likely reason for the incomplete removal of the EPS.
3.2.4. Sodium chloride
3.3. EPS removal – PHA dissolving step
3.4. PHA recovery
Fig. 3(a) shows the amounts of recovered PHA from aerobic granules using three different volumes of sodium hypochlorite. The highest PHA recovery yield was 89% of the cell dry weight (CDW) and was observed when using 12.5 mL of NaOCl. As complete removal of EPS was observed for NaOCl method, guanine is postulated that all PHA has been extracted out from aerobic granules by using 12.5 mL of NaOCl. Based on this PHA recovery yield, it can be inferred that aerobic granules possesses high capacity in accumulating PHA. It matches the highest PHA yield in mixed culture that has been reported to date (Johnson et al., 2009).