Co-Production of Polyhydroxyalkanoates and Carotenoids by Haloferax mediterranei DSM 1411

Polyhydroxyalkanoates (PHA) are naturally occurring biopolymers that possess high performance material properties such as biodegradability and biocompatibility. PHA can be produced from renewable carbon sources. However, the industrial production of PHA is still hindered by the costly feed materials. Co-production of other high-value products in addition to PHA can be helpful in alleviating overall production of PHA. In this work, the effect of temperature on PHA and carotenoids co-production by Haloferax mediterranei DSM 1411 was investigated using 1% glucose as carbon source. Under batch fermentation at 37°C, Haloferax mediterranei synthesized 3.37 g L^-1 PHA with concomitant production of 0.76 mg L^-1 of carotenoids at 144 h. The maximum dry cell weight (DCW) was 6.54 g L^-1 and PHA content was 51.6%, with 3-hydroxyvalerate (3HV) fraction of 8.01 mol%. By increasing temperature to 42°C, an increase in PHA and carotenoids production was noticed reaching a maximum of 3.99 g L^-1 and 0.92 mg L^-1, respectively, at 120 h. Likewise, DCW was increased to 7.06 g L^-1 and PHA content was 56.5%, with 3HV fraction of 8.42 mol%.