Preparation and characterization of a poly(β-hydroxyoctanoate) latex produced by Pseudomonas oleovorans

A latex of poly(beta-hydroxyoctanoate) was obtained from Pseudomonas oleovorans grown at high cell density on sodium octanoate. A fermentation using a pH-stat control of octanoate concentration as well as the purification steps using sodium hypochlorite were described. It was observed that latex stabilization occurred spontaneously due to the persistence around the polymer granules of the murein sacculus, which envelopes the bacterial cell. Films were processed by casting and evaporating the polymeric aqueous suspension and were characterized by scanning electron microscopy, wide-angle X-ray scattering, dynamic mechanical analysis, and tensile tests. It was shown that the optimal conditions for the bacteria digestion correspond to a hypochlorite concentration between 21 and 26 mmol of NaOCl/g of biomass. These conditions enable latex stabilization and satisfactory mechanical properties of the resulting film.