Reducing off-Flavour in Commercially Available Polyhydroxyalkanoate Materials by Autooxidation through Compounding with Organoclays

Abstract

Polyhydroxyalkanoates (PHAs) are nowadays considered competent candidates to replace traditional plastics in several market sectors. However, commercial PHA materials exhibit unsatisfactory smells that can negatively affect the quality of the final product. The cause of this typical rancid odour is attributed to oxidized cell membrane glycolipids, coming from Gram-negative production strains, which remain frequently attached to PHAs granules after the extraction stage. The aim of this research is the development of customised PHA bio-nano-composites for industrial applications containing organomodified nanoclays with high adsorbance properties able to capture volatile compounds responsible for the displeasing fragrance. To this end, a methodology for the detection and identification of the key volatiles released due to oxidative degradation of PHAs has been established using a headspace solid-phase microextraction technique. We report the development of nine bio-nano-composite materials based on three types of commercial PHA matrices loaded with three species of nanoclays which represent a different polar behaviour. It has been demonstrated that although the reached outcoming effect depends on the volatile nature, natural sepiolite might result in the most versatile candidate for any the PHA matrices selected.

Halloysite Nanotubes Coated by Chitosan for the Controlled Release of Khellin

“…In recent years, hybrid nanomaterials composed by biopolymers and inorganic nanoparticles have attracted growing interest within several fields, including biomedicine [ 1 , 2 , 3 , 4 , 5 ], pharmaceutics [ 6 , 7 , 8 , 9 , 10 ], food packaging [ 11 , 12 , 13 , 14 , 15 ], remediation [ 16 , 17 ] and cultural heritage [ 18 , 19 , 20 ]. As evidenced in a recent review [ 21 ], both ionic and non-ionic polysaccharides can be suitable polymers for the development of functional nanocomposites, with excellent performances in terms of thermal stability, barrier properties and mechanical behavior.…”

Pilot scale production and evaluation of mechanical and thermal properties of P(3HB) from Bacillus megaterium cultivated on desugarized sugar beet molasses

“…The strands were cooled at room temperature on a C4N-B belt conveyor with a length of 3.2 m (Robotunits GmbH, Austria) and subsequently cut to granules using a Rieter Primo 100 granulator. Prior to injection molding the granules of the P(3HB) synthesized from DSBM and the commercial PHA grades, which are described in Table 1 according to the literature, [32][33][34][35][36] were dried in a Heraeus dryer with circulating air at a temperature of 105 C for approximately 18 h. Molding of tensile and flexural test bars was carried out on a Battenfeld HM60/210 injection molding machine. The machine settings, which were kept constant for all different PHA grades, included a metering stroke of 38 cm 3 , a back pressure of 5 MPa and a dosing speed of 200 mm/s.…”

Bio-Based Polymers for Engineered Green Materials

“…These macromolecules are biodegradable polyesters and their synthesis is affected by several parameters, of which concentration of substrate and cycle length are fundamental [26]. These promising bio-material often have an unpleasant smell and limited mechanical properties, which can be reduced by adding organoclays [27,28].…”