Production of phenoxy-substituted poly(3-hydroxyalkanoates) (PHA) by Pseudomonas mediterranea

Some Pseudomonas species can synthesize PHAs from carbon sources bearing phenyl and phenoxy groups. However, the growth and polymer yields obtained with these carbon sources are very scarce. To improve PHA yield, co-feeding strategies are used. In this case, the resulting PHA is often a random copolymer with repeating units obtained from both substrates. For example, when Pseudomonas putida was grown on 11-phenoxyundecanoic acid (11-POU) and octanoate, the bacterium synthesized the copolyesters composed of aromatic and aliphatic monomers poly (5POHV-co-7POHH-co-3-hydroxy-9-phenoxynonanoate-co-3-hydroxyalkanoates). In previous studies we showed that in Pseudomonas mediterranea, glutamine as carbon and nitrogen source, in cofeeding strategy, promotes the uptake of second carbon sources and increases PHA yield. Moreover, we also observed that P. mediterranea is able to use 11-POU to grow and synthesize PHA at very low levels. In this work, we compared the production and the composition of polymers using glutamine or sodium octanoate as cofeeders in 11-phenoxyundecanoic acid-fed cultures (SO-11POU and GLN-11POU respectively). The structural characterization of the polymers was performed through NMR analysis.