Lactic acid containing polymers produced in engineered Sinorhizobium meliloti and Pseudomonas putida

Abstract

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 (Pct Cp , Pct532) and a modified Pseudomonas sp. MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1 Ps6-19 , PhaC1400), into phaC mutant strains of the native polymer producers Sinorhizobium meliloti and Pseudomonas putida. Both phenotypic analysis and gas chromatography analysis indicated the synthesis and 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. 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.

Microbial Production of Biodegradable Lactate-Based Polymers and Oligomeric Building Blocks From Renewable and Waste Resources

“…This discovery laid the foundation for the advancement of the system by varying monomer ratios and composition ( Nduko et al, 2015 ; Nduko and Taguchi, 2019 ). Subsequently, a similar procedure using an evolved PHA synthase and PCT has been recruited by other researchers to produce LA-based polyesters in engineered microorganisms ( Yang et al, 2013 ; Choi et al, 2019 ; Tran and Charles, 2020 ).…”

“…In another study, Tran and Charles (2020) introduced a broad-host-range plasmid (pTAM) that was expressing codon optimized PCT and engineered Pseudomonas sp. MBEL 6–19 PHA synthase 1 (PhaC1Ps6-19, PhaC1400) into phaC mutant strains of Sinorhizobium meliloti and P. putida , which are native PHA producers.…”

A Review of the Recent Developments in the Bioproduction of Polylactic Acid and Its Precursors Optically Pure Lactic Acids

“…Additionally, the aromatic polyesters poly(3HB-co-D-phenyllactate) can be produced from glucose as a sole carbon source by additional expression of Ralstonia eutropha ketothiolase (phaA) and reductase (phaB) genes [63]. As another novel biopolymer, the quaterpolymer P(3HB-co-LA-co-3HHx-co-3HO) was produced in P. putida with polymer content of 42% dry cell weight when cultured in defined media with the addition of sodium octanoate [20].…”

“…In addition, the toxicity caused by the use of metal catalysts seriously affects the applications of PLA as biomedical and food-packaging materials [11]. As an alternative to the traditional production process, one-step fermentative production of PLA has recently been developed by employing metabolically engineered microorganisms (Figure 2b), such as Escherichia coli [15][16][17][18][19], Sinorhizobium meliloti and Pseudomonas putida [20].…”

The variation of promoter strength in different gene contexts

“…PHB: Polyhydroxybutyrate. pTH1227 pct532 phaC1400 (codon-optimized) pTAM derivative, P 0 promoter-a substitute for lacI q -P tac pTAM derivative, P 1 promoter-a substitute for lacI q -P tac pTAM derivative, P 2 promoter-a substitute for lacI q -P tac pTAM derivative, P 3 promoter-a substitute for lacI q -P tac pTAM derivative, P 4 promoter-a substitute for lacI q -P tac pTAM derivative, P 5 promoter-a substitute for lacI q -P tac [24] [5] [25] This study…”