189. Production of polyhydroxyalkanoate copolymers containing 4-hydroxybutyrate in engineered Bacillus megaterium
Andrew J. Cal, Rena E. Kibblewhite, W. Dirk Sikkema, Lennard F. Torres, William M. Hart-Cooper, William J. Orts and Charles C. Lee; International Journal of Biological Macromolecules; (2020); DOI: 10.1016/j.ijbiomac.2020.12.015
Despite being used as a common platform for the commercial production of many biochemicals, Bacilli are often overlooked as a source of industrial polyhydroxyalkanoates (PHAs), biodegradable plastic replacements. In addition to having a robust expression system, the lack of lipopolysaccharides and ease of lysis make Bacilli an attractive host for the production of PHAs. In this work, a Bacillus megaterium strain was engineered to generate poly(3-hydroxybutyrate-co-4-hydroxybutryate) (P[3HB-co-4HB]) copolymers, which are among the most useful and industrially-relevant copolymers. These copolymers had lower modulus and increased toughness, thus making the copolymer suitable for a broader range of applications. Due to high metabolic flux through succinate, the engineered B. megaterium strain produced P(3HB-co-4HB) with >10% mol fraction 4HB from glucose, without the use of highly regulated and expensive precursors or potentially damaging truncation of central biochemical pathways.