Production of PHB from Chicory Roots - Comparison of Three Cupriavidus necator Strains

Chicory roots from hydroponic salad cultivation are an abundant food residue in Navarra (Spain) that are underutilized to date. Aiming at a holistic utilization of resources, we report here the first process using chicory root hydrolysate for the production of poly([R]-3-hydroxybutyrate) (PHB). The polymer can be used for packaging material made for the locally produced vegetables. In the first step, we developed a pre-treatment process to obtain a hydrolysate, which contained 34 g L-1 sugars and 0.7 g L-1 total Kjeldahl nitrogen. This hydrolysate was used as fermentation substrate for three PHB-producing strains. Cupriavidus necator DSM 428 reached a dry biomass concentration of 11.3 g L-1 with a PHB content of 66 % in dry mass within 5 days. C. necator DSM 531 yielded 3.5 g L-1 dry biomass containing 46 % PHB within the same period. C. necator DSM 545 was superior over the other two in that 14.0 g L-1 of biomass containing 78 % PHB after only 3 days were obtained. These results show that even within the same species, the productivities on natural substrates are very different. The produced polymers were extracted using chloroform, and several thermo-physical parameters are in good accordance with published data. Overall, our holistic approach and the encouraging results prove that chicory roots are a viable fermentation substrate for PHB-production.This work was conducted as a part of the LEAD-ERA Project CARBIO, which was financed by the Basque Goverment and co-financed by the European Regional Development Fund (ERDF) of the European Union

Lentil By-products as a Source of Protein for Food Packaging Applications

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Theophylline release from poly(acrylic acid-co-acrylamide) hydrogels

Hydrogels are hydrophilic polymers that swell to an equilibrium volume in the presence of water but preserve their shape. The dynamic swelling behavior of poly(acrylic acid-co-acrylamide) copolymers, at 37 °C, was investigated. It was observed that the liberation mechanism was non-Fickian. Diffusion coefficients according to Ficks law as a function of concentration of N,N?-methylenebisacrylamide and results on the effects of crosslink density on the release of theophylline are reported

Swelling kinetics of poly(acrylamide)/poly(mono-n-alkyl itaconates) hydrogels

Hydrogels of mono-n-alkyl itaconate/N-acrylamide have been synthesised. The swelling process at three different pH values (acid, neutral and basic) has been studied. The experimental data indicate that our hydrogels follow second-order swelling kinetics. According to this, the kinetic constant, K∞, and the swelling capacity at equilibrium, W∞, have been calculated. The influence of the solvent pH and the molar mass of the mono-n-alkyl itaconate monomeric unit has been analysed. It seems that the general balance between the hydrogen bonding and the hydrophobic interactions regulates the swelling process of these hydrogels. © 1996 SCI

Swelling kinetics of poly(acrylamide)/poly(mono-n-alkyl itaconates) hydrogels

Hydrogels of mono-n-alkyl itaconate/N-acrylamide have been synthesised. The swelling process at three different pH values (acid, neutral and basic) has been studied. The experimental data indicate that our hydrogels follow second-order swelling kinetics. According to this, the kinetic constant, K?, and the swelling capacity at equilibrium, W?, have been calculated. The influence of the solvent pH and the molar mass of the mono-n-alkyl itaconate monomeric unit has been analysed. It seems that the general balance between the hydrogen bonding and the hydrophobic interactions regulates the swelling process of these hydrogels. © 1996 SCI