Sunday, May 3, 2009
6-22
Optimization process using experimental design for biosurfactant production
Cristina Ferraz, PhD student at the northeast biotechnology network - RENORBIO, Universidade Federal de Sergipe, Cidade Universitária Prof. "José Aloísio de Campos", Rosa Elze, São Cristóvão, Brazil, Álvaro A. Araújo, Departamento de Engenharia de Alimentos, Universidade Federal de Sergipe, Cidade Universitária Prof., São Cristóvão, Brazil, and Roberto R. Souza, Departamento de Engenharia Quimica, Universidade Federal de Sergipe, Cidade Universitária Prof. "José Aloísio de Campos", São Cristóvão, Brazil.
Biosurfactants are compounds produced by microorganisms. They present a hydrophilic portion (water soluble) and a hydrophobic portion (water insoluble). These molecules are capable of reducing surface and interfacial tensions in both aqueous solutions and hydrocarbon mixtures, which make them potential compounds for enhancing oil recovery and deemulsification processes. Biosurfactant production using a bacterial strain was studied in this work. The microorganism considered was isolated in previous studies and identified in this work as Serratia sp. Initially three media were tested for the biosurfactant production, and the medium 1 presented the best results, after being used in an optimization process, which was conducted in erlenmeyer flasks in a shaker through Experimental Design. During the optimization, we studied the concentrations of the medium components, such as peptone and glycerol, also fermentation temperature and initial pH were studied. The optimum values for biosurfactant production using Serratia sp. were between 0.17 and 0.4% for peptone and between 2.0 and 3.14% for glycerol, at 35ºC and pH 7.0. Moreover, some properties of the biosurfactant were studied, for example, its emulsifying capacity and stability at different pH values and temperatures.