*Article* **Bioconversion of Mixed Alkanes to Polyhydroxyalkanoate by** *Pseudomonas resinovornas***: Upcycling of Pyrolysis Oil from Waste-Plastic**

**Jong-Min Jeon 1, So-Jin Park 1,2, Ye-Seung Son 1, Yung-Hun Yang <sup>3</sup> and Jeong-Jun Yoon 1,\***


**Abstract:** Polyhydroxyalkanoate (PHA) is a biodegradable plastic that can be used to replace petroleum-based plastic. In addition, as a medium-chain-length PHA (mcl-PHA), it can be used to provide elastomeric properties in specific applications. Because of these characteristics, recently, there has been much research on mcl-PHA production using inexpensive biomass materials as substrates. In this study, mcl-PHA producers were screened using alkanes (n-octane, n-decane, and n-dodecane) as sources of carbon. The amount of PHA produced by *Pseudomonas resinovorans* using sole n-octane, n-decane, or n-dodecane was 0.48 g/L, 0.27 g/L, or 0.07 g/L, respectively, while that produced using mixed alkane was 0.74 g/L. As a larger amount of PHA was produced using mixed alkane compared with sole alkane, a statistical mixture analysis was used to determine the optimal ratio of alkanes in the mixture. The optimal ratio predicted by the analysis was a medium with 9.15% n-octane, 6.44% n-decane, and 4.29% n-dodecane. In addition, through several concentration-specific experiments, the optimum concentrations of nitrogen and phosphorus for cell growth and maximum PHA production were determined as 0.05% and 1.0%, respectively. Finally, under the determined optimal conditions, 2.1 g/L of mcl-PHA and 60% PHA content were obtained using *P. resinovorans* in a 7 L fermenter.

**Keywords:** polyhydroxyalkanoate; mcl-PHA; *Pseudomonas resinovorans*; mixed alkane
