Cost-Effective PHA Production from Plant Oils in a Thermotolerant Strain via Inducible System and Metabolic Optimization

Abstract

Production of Polyhydroxyalkanoates (PHAs) on an industrial scale depends on using low-cost feedstock and minimizing cooling costs, which can account for up to 50% and 20% of the total cost, respectively. Plant oils are cost-effective and energy-rich carbon sources. A thermotolerant bacterium can grow at temperatures up to 50°C, which enhances oil solubility and enables efficient metabolism of long-chain fatty acids. However, this strain lacks the ability of lipid metabolism. To address these limitations, we aim to identify a suitable inducible promoter and introduce lipid metabolism. Additionally, this strain possesses PHA biosynthetic operons, allowing it to synthesize PHA. However, compared to conventional PHA-producing strains, it shows relatively low PHB content. Therefore, we also aim to enhance PHA production through optimization of PHA biosynthesis gene expression. Overall, this study aims to establish a cost-effective PHA production platform by engineering an inducible system and enhancing both oil metabolism and PHA biosynthesis.