Polyhydroxyalkanoate (PHA) is one of the most promising biopolymers with the advantages of biodegradable biocompatible and renewable. A glycerol-fed PHA-producing mixed culture was enriched in a feast-famine regime. The substrate versatility and PHA production capacity of the mixed culture were studied using acetate,propionate,butyric, glucose and lactate as substrate, respectively. The results showed a high PHA content with lactate and acetate as the sole substrate, respectively. When acetate and propionate were used as mixed substrates to produce PHA, the PHA contents increased with the proportion of acetate and the PHA content was the highest as the ratio acetate/propionate was 3:1.The results based on the modeling of simultaneously storage and growth and the linear fitting under three different acetate/propionate ratios showed that there was a linear relation between PHA synthesis and OUR. Thus, it is feasible to estimate PHA content based on in-situ real-time monitoring data of OUR.
Keywords: OUR; PHA; mixed cultures; mixed substrates; real time on-line monitoring.