Poly 3-(hydroxyalkanoates) produced from oily substrates by Pseudomonas aeruginosa 47T2 (NCBIM 40044): Effect of nutrients and incubation temperature on polymer composition

In the course of the production of rhamnolipids with surface-active properties, Pseudomonas aeruginosa 47T2, when cultivated in mineral medium with waste cooking, accumulates polyhydroxyalkanoates (PHA) up to 36% of its cell dry weight (CDW) with the following composition (%): 9.4 C8:0; 47.8 C10:0; 15.3 C12:0; 7.8 C12:1; 1.0 C14:0; 11.4 C14:1; 7.0 C14:2. At the same time, average molecular weights, which ranged between 38.8 and 37.1 kDa were determined making use of the Mark–Houwink relationship and the intrinsic viscosities determined for tetrahydrofuran (THF) at 40 °C as solvent. The resulting polymers varied in the nature of the monomers and number. The highest production rate was at 37 °C, 8.2 mg of PHA/(g of residual biomass h) and the amounts of saturated and unsaturated compounds were strongly temperature dependent. Finally, the effect of the incubation temperature, carbon and nitrogen sources and the concentration of potassium phosphate in relation to the polymer composition are evaluated. PHA monomer compositions were determined by GC–MS and corroborated by NMR spectra analysis.