Abstract
PHA (Polyhydroxyalkanoate) known as carbon storage polymer in microorganisms recently draws attention as a biodegradable plastic. It is known that the microorganisms in activated sludge can produce PHAs, and PHA production by activated sludge is worth being focused in the aspects of the recovery of organic from wastewater etc. In this research, the PHA production using activated sludge was investigated with special focus on the effect of substrate composition on the PHA structure and the influence of presence of nitrogen compounds on the PHA production efficiency. The results showed that the ratio of 3HB and 3HV monomers in the PHA produced was regulated (3HV ratio is 3-84%) by changing the ratio of acetate and propionate in substrate. It was also indicated that activated sludge can produce PHA under non-nitrogen-limitting condition. In general PHA production is inhibited under this condition.
