3-24: A kinetic modeling study for biosurfactant production using cassava wastewater

Monday, April 29, 2013
Exhibit Hall
Cristina Ferraz, Rogério Luz Pagano, Waldjer Melo Dantas and Douglas da Cruz Santos, Department of Chemical Engineering, Federal University of Sergipe, São Cristóvão, Brazil
Biosurfactants are biologically surface active compounds produced by several microorganisms using different substrates. The cassava wastewater is an agro industrial waste from cassava manufacturing with high carbohydrate content and low cost. This waste represents an alternative substrate for biosurfactant production. However, there are few studies about kinetic mechanism and parameter estimation in the biosurfactant production. So, this study proposes a simplified kinetic where the different models in the literature have been adapted to the studied process and its parameters were fitted to experimental data. The kinetic models were implemented and solved by using subroutines in Fortran language. The mathematical model solution was compared with the experimental data through the error function defined by the least square fitting. In order, to find the function minimum value a heuristic algorithm called Particle Swarm Optimization (PSO) was applied. The PSO is an optimization algorithm based on the social behavior of an animal collection and has an important characteristic to find a global minimum. The substrate concentration, cell amount and surface tension value were adjusted with the values provide from the mathematical model and, this way, the kinetic constants were determined. The results showed a accentuate decrease of the surface tension of the solution and the estimated kinetic constants provide a good agreement between experimental data and theoretical values.

Keywords: biosurfactant, cassava, kinetic model, parameter estimation and PSO.