This study demonstrates that novel polymer production can be achieved by introducing pTAM, a broad-host-range plasmid expressing codon-optimized genes encoding Clostridium propionicum propionate CoA transferase (PctCp) and a modified Pseudomonas sp. MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1Ps6-19), into phaC mutant strains of the native polymer producers Sinorhizobium meliloti and Pseudomonas putida. Both phenotypic analysis and gas chromatography analysis indicated the synthesis

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... d accumulation of biopolymers in S. meliloti and P. putida strains. Expression in S. meliloti resulted in the production of PLA homopolymer up to 3.2% dried cell weight (DCW). The quaterpolymer P(3HB-co-LA-co¬¬-3HHx-co¬¬-3HO) was produced by expression in P. putida. The P. putida phaC mutant strain produced this type of polymer the most efficiently with polymer content of 42% DCW when cultured in defined media with the addition of sodium octanoate, while the greatest LA fraction (4% mol) was achieved in the same strain cultured in LB with the addition of lactic acid. This is the first report, to our knowledge, of the production of a range of different biopolymers using the same plasmid-based system in different backgrounds. In addition, it is the first time that the novel polymer (P(3HB-co-LA-co¬¬-3HHx-co¬¬-3HO)), has been reported being produced in bacteria.