Impact of different bacterial strains on the production, composition, and properties of novel polyhydroxyalkanoates using crude palm oil as substrate

Abstract

Polyhydroxyalkanoates (PHAs) are a group of biodegradable polymers produced from renewable sources by prokaryotic biocatalysts, accumulated intracellularly for energy and carbon storage. In the present study, production and characterization of PHAs synthetized by Cupriavidus necator (IPT 026 and IPT 027) and Burkholderia cepacia (IPT 119 and IPT 400) were evaluated using crude palm oil (C16:0 = 26.44 %, C18:1 = 54.50 %, C18:2 = 13.41 %) as substrate (15 g L-1 crude palm oil, pH 7.0, 180 rpm, 72 h). All strains were able to synthesize novel PHA copolymers (0.10-1.45 g L-1), and IPT 027 displayed the highest production. Copolymers monomeric composition (Mw = 173.78-389.30 kDa) was comprised mostly of hydroxyhexadecanoate (41.43-53.15 %) and hydroxy-9-octadecenoate (14.91-29.61 %). PHAs were predominantly amorphous, showed low polydispersity, and good thermal stability (Tonset ≥ 283 °C), which increased proportionally to crystallinity. Crude palm oil constitutes an emerging alternative for PHAs production, and microorganism strains strongly affect polymer accumulation, monomeric composition, molar mass, and properties.