Modelling And Simulation Of The Adsorption Of The Lipase From Geotrichum Sp. On Hydrophobic Interaction Columns

The Langmuir model fitted well the adsorption isotherms of lipase on the hydrophobic resin. The model parameters, Qm and kd, were affected by NaCl concentration: Qm increased from 31 to 80 U g-1 resin, and kd changed from 9.4 to 3 U ml-1. Column modelling and the simulation data were compared with the experimental data with good agreement. The highest achieved column efficiency was 71%. Notations: C: lipase concentration in solution (U ml-1); C*: lipase concentration in solution at equilibrium (U ml-1); Co: lipase concentration in the feed (U ml-1); d: resin particle diameter (cm); D: enzyme molecular diffusivity (cm2 min-1); E: axial dispersion coefficient (cm2 min-1); K: global mass transfer coefficient (cm2 min-1); kd: kinetic constant (U ml-1); k1: adsorption kinetic constant (ml U-1 min-1); k2: desorption kinetic constant (min-1); L: bed height (cm); Q: amount of adsorbed lipase in the resin (U ml-1 resin); Q*: amount of adsorbed lipase in the resin at equilibrium (U ml-1 resin); Qm: maximum adsorption capacity of the resin (U ml-1 resin); R: column radius (cm); Rs: rate of lipase adsorption (U ml-1 resin min-1); υ: superficial velocity (cm min-1); t: time; Z: column length (cm); ε: bed porosity. Subscript: i: time, j: position.2310781786Baillargeon, M.W., McCarthy, S.G., Geotrichum candidum NRRL Y-533 lipase: Purification, characterization and fatty acid specificity (1991) Lipids, 26, pp. 831-836Balcão, V.M., Vieira, M.C., Maleata, F.X., Adsorption of protein from several commercial lipase preparations onto hollow-fiber membrane module (1986) Biotechnol. Progr., 12, pp. 164-172Chase, H.A., Prediction of the performance of preparative affinity chromatography (1984) J. Chromatogr., 297, pp. 179-202Diogo, M.M., Silva, S., Cabral, J.M.S., Queiroz, J., A hydrophobic interaction on chromatography of Chromobacterium viscosum lipase on polypropylene glycol immobilised on Sepharose (1999) J. Chromatogr., 849, pp. 413-419Gitlesen, T., Bauer, M., Adlercreutz, P., Adsorption of lipase on polypropylene powder (1997) Biochim. Biophys. Acta, 1345, pp. 188-196Gustavsson, P.-E., Axelsson, A., Larsson, P.-O., Superporous agarose on bead as hydrophobic interaction chromatography support (1999) J. Chromatogr., 830, pp. 275-284Jacobsen, T., Olsen, J., Allerman, K., Substrate specifities of Geotrichum candidum lipase preparations (1990) Biotechnol. Lett., 12, pp. 121-126Kamimura, E.S., Mendieta, O., Sato, H.H., Pastore, G.M., Maugeri, F., Production of lipase from Geotrichum sp. and adsorption studies on affinity resin (1999) Brazilian J. Chem. Eng., 16, pp. 102-112Macêdo, G.A., Park, Y.K., Pastore, G.M., Partial purification and characterization of an extracellular lipase from a newly isolated strain of Geotrichum sp. (1997) Rev. Microbiol., 28, pp. 90-95Noriega, J., Tejada, A., Magaña, I., Ortega, J., Guzman, R., Modelling column regeneration effects on dye-ligand affinity chromatography (1997) Biotechnol. Prog., 13, pp. 296-300Phillips, A., Pretorious, H.J., Purification and characterization of an extracellular lipase of Galactomyces and Geotrichum (1991) Biotechnol. Lett., 13, pp. 833-838Porath, J., Salt promoted adsorption: Recent developments (1986) J. Chromatogr., 376, pp. 331-341Warwel, S., Borgdorf, R., Substrate selectivity of lipases in the esterification of cis-trans-isomers and positional isomers of conjugated linoleic acid (CLA) (2000) Biotechnol. Lett., 22, pp. 1151-115

Biodegradable Films Based on Blends of Gelatin and Poly (Vinyl Alcohol): Effect of PVA Type or Concentration on Some Physical Properties of Films

The aim of this work was to develop biodegradable films based on blends of gelatin and poly (vinyl alcohol) (PVA), without a plasticizer. Firstly, the effect of five types of PVA with different degree of hydrolysis (DH) on the physical properties of films elaborated with blends containing 23.1% PVA was studied. One PVA type was then chosen for the study of the effect of the PVA concentration on the mechanical properties, color, opacity, gloss, and water solubility of the films. The five types of PVA studied allowed for films with different characteristics, but with no direct relationship with the DH of the PVA. Therefore, the PVA Celvol (R) 418 with a DH = 91.8% was chosen for the second part, because they produced films with greater tensile strength. The PVA concentration affected all studied properties of films. These results could be explained by the results of the DSC and FTIR analyses, which showed that some interactions between the gelatin and the PVA occurred depending on the PVA concentration, affecting the crystallinity of the films.FAPESP[05/57781-8]GGDS[05/54418-0]PVAB[05/54688-7]CNPqPJA