Extração sólido-líquido de ficocianina de Arthospira platensis usando líquido iônico prótico (2-HEAF): modelagem dos dados experimentais

Abstract

The phycocyanin protein’s pigment is a compound of high value. It has great interest of the pharmaceutical industry due to its therapeutic properties. It is an anti-inflammatory, antioxidant and hepatoprotective product, and also used as blue natural colorant in the food and cosmetic industry. Futhermore, this pigment has other applications, as fluorescence markers. Phycocyanin is a group of phycobiliproteins, which are pigments that capture light energy and transfer it to the reactive center of photosynthesis. They are found in the marine micro-algae, such as Arthrospira (Spirulina) plantesis. However, the extraction of this compound is difficult due to the multilayer cell wall of the microalga and the large amount of contaminants. The solvent traditionally used in the extraction of these biomolecules is sodium phosphate buffer. However, other solvents such as ionic liquids are gaining notoriety in the scientific community due to their beneficial properties to the environment and to the extraction process. The color quality, the phycocyanin properties and the efficiency of the extraction are influenced by temperature, pH, solvent and another parameters and properties. The aim of this work was to evaluate the effect of temperature and solvents. Sodium phosphate buffer at pH 7 and sodium phosphate buffer + protonic ionic liquid N-methyl-2- (2-HEAF) at pH 8 were used. The biomass/solvent ratio was 2:3 m / v in the solid-liquid extraction process. The kinetic and thermodynamic parameters were obtained. Under optimum conditions, the concentrations and yield obtained were 1.29 g L-1 and 0.86 g L-1; 19.3 mg g-1 and 12.93 mg g-1 in buffer and buffer + (2-HEAF), respectively. The addition of the ionic liquid in the buffer increased the activation energy from 179.24 KJ mol-1 to 225.93 KJ mol-1, slowing the reaction rate. The increase in temperature increased the extraction rate, k, and the equilibrium constant, Ce. However, the continuous temperature increase showed protein degradation. The enthalpy values of activation, free energy of Gibbs and entropy of activation showed that the buffer presented greater stability than the ionic liquid for the used method.