Estudo da adsorção de biomoléculas (albumina de soro bovino e lisozima) em materiais mesoporosos
Dissertation (Ms) 09/09/2016
Karina Alexandre Barros Nogueira
The adsorption of proteins on solid surfaces has application in many different fields such as biomedicine, biomolecule separation, effluent treatment. This study investigates the adsorption of two biomolecules (bovine serum albumin – BSA and lysozyme – LYS) on mesoporous materials obtained from two different sources, a layered double hydroxide and a mesoporous silica. In the first part of this study , HDL (layered double hydroxide) was synthesized through the coprecipitation method using two different types of metals, zinc (Zn-Al) and magnesium (Mg-Al). The adsorption of BSA was evaluated in batch system to check the influence of the buffer solution, the contact time and the initial concentration. Experiments fixed bed were also performed to evaluate the dynamics of adsorption of BSA in HDL as well as regeneratable material. The maximum amount of adsorbed BSA was in 50mM sodium acetate buffer at pH 4.8 (the isoelectric point of the protein) to the Mg-Al LDH and 50mM MES buffer at pH 6.7 to the Zn-Al LDH. For Langmuir and Langmuir-Freundlich models we got 338.74 mg g-1 and 346.54 mg g-1 for Zn-Al LDH and 196.12 and 197.80 mg g-1 for Mg-Al LDH respectively. The results indicate that for the double lamellar hydroxides the charge density of the Zn-Al LDH with the contributions of other interactions such as hydrogen bonding or Van der Waals interaction promotes the better adsorption in 50mM MES pH 6.7 buffer of serum albumin bovine. In the second part of the SBA-15 material was synthesized by hydrothermal method with the addition of the componente 1,3,5-trimethylbenzene (TMB) and used in adsorption of biomolecules dissolved in solutions with different concentrations of sodium chloride. The maximum amount of BSA was adsorbed in 50mM sodium acetate buffer at pH 4.8 (the isoelectric point of the protein) and the LYZ was adsorbed in 50mM Tris HCl buffer at pH 10. The Langmuir model obtained 403.63 mg.g -1 for adsorption of BSA and 677.93 mg g-1 for adsorption of LYS. For adsorption results with LYZ revealed the occurrence of precipitation due to the phenomenon of “salting-out” when there is addition of salt to the solution and thus the reduction in protein adsorption capacity of the material.
