Demonstration of the adhesive properties of the medium-chain-length polyhydroxyalkanoate produced by Pseudomonas chlororaphis subsp. aurantiaca from glycerol

Pseudomonas chlororaphis subsp. aurantiaca (DSM 19603) was grown on crude glycerol from biodiesel production to produce a medium-chain-length polyhydroxyalkanoate (mcl-PHA), composed of 3-hydroxydodecanoate (43 ± 1.8 mol%), 3-hydroxydecanoate (29 ± 3.1 mol%), 3-hydroxytetradecanoate (12 ± 0.4 mol%), 3-hydroxyoctanoate (10 ± 1.5 mol%) and 3-hydroxyhexanoate (6 ± 0.3 mol%). The biopolymer had an average molecular weight of 1.1 × 10⁵ Da, with a polydispersity index of 1.5, and was semi-crystalline, as shown by its crystallinity index of 37 ± 0.2%. It had low melting (44 °C) and glass transition (−48 °C) temperatures, and was thermally stable up to 285 °C. The biopolymer films were elastic and translucid, were hydrophobic and presented relatively high permeability to oxygen and carbon dioxide. The films demonstrated to have good adhesion properties towards porcine skin and human skin. The tension (61.1 ± 20.6 kPa) and shear (12.7 ± 2.14 kPa) bond strength of the mcl-PHA for porcine skin suggest its potential as a biomaterial for the development of novel natural adhesives for wound closure or wound dressings.