Production and characterization of polyhydroxyalkanoates films produced by Cupriviadus necator from agro-industrial residues

ABSTRACT

Polyhydroxyalkanoates (PHA) are a viable alternative to replacing traditional plastics, harmful to nature. The objective of this study was to evaluate the production of PHA by Cupriviadus necator using agro-industrial residues, its physicochemical characterization, and of the membranes produced. Cell growth and PHA production were compared in three carbon sources: residual glycerol, whey cheese with and without a mineral solution. After cultivation, the biopolymer was extracted and characterized by FTIR and 1D and 2D NMR experiments. Membranes containing 5.0% of PHA had their physicochemical properties measured for mechanical properties, color, and water vapor permeability. The results demonstrated that the yield of PHA.g^-1 of biomass was higher for cultivation using residual. Yet the PHA.L^-1 was higher in cultures with whey cheese. The NMR and FTIR result allowed to characterize the molecular structure of PHA produced. It was calculated 8 carbon atoms in the methylene main chain and a maximum of 13 carbons (Poly-3-hydroxytridecanoato) in the polymer side chain. The membranes showed a strong whiteness tendency as well as a high opacity, expected low water vapor permeability, and rigidity. In conclusion, mechanical properties indicated that the formed PHA membranes could be applicable to plastic packaging in substitution for petroleum derivatives.

Keywords
PHA; residual glycerol; whey cheese; film plastic; characterization