Production of short-chain-length and medium-chain-length polyhydroxyalkanoate copolymer through systems metabolic engineering

Abstract

Since there are severe global climate change and depletion of petroleum-based resources, it is essential to find sustainable alternative material replacing conventional plastic material based on petrochemical industries. Polyhydroxyalkanoate is promising substitute material with the advantages of biodegradability. Poly(3-hydroxybutyrate-co-lactate) is the microbial polyester that can improve poor material properties of poly(3-hydroxybutyrate) with an additional incorporation of lactate. In this study, the different expressions of propionyl-CoA transferase mutant and PHA synthase mutant were introduced in metabolically engineered Escherichia coli, and optimal production system showed 125.9 g/L of P(3HB-co-5.9mol% LA). Moreover, the production of polyester containing medium-chain-length monomer from fatty acid or glucose was discussed for enhanced material properties. Furthermore, the extraction of PHA granules based on alkaline hydrolysis and analysis of material properties were examined.