Kinetical models for facultative bacteria Cupriavidus Necator behavior on oil degradation from comestible oil wastewater industry

Abstract

For this thesis, kinetic models were proposed to study the degradation of oils and fats from wastewater from edible oil industries and the production of polyhydroxybutyrate (PHB) through the use of the Cupriavidus necator bacteria; some of these models for growth are Monod and a modified Monod model. For the development of kinetic models, experimental data previously reported in Mexico's wastewater industry was used. The wastewater conditions for the production of PHB must be at a temperature of 30 ºC, at a neutral pH, and free of toxic substances. These conditions make it possible to obtain up to 70% PHB in cell dry weight (CDW). The metabolism of Cupriavidus necator under aerobic conditions was reviewed in the literature, with which four biological processes were proposed: heterotrophic growth using fructose as a carbon source, heterotrophic growth using fatty acids as a carbon source, hydrolysis, and heterotrophic lysis. For constructing a mathematical model that describes the kinetical models, the matrix notation was used, which describes a stoichiometric matrix and a matrix of conservative components, which were nitrogen, phosphorus, and organic matter measured as chemical oxygen demand (COD). A kinetic for each process was considered, allowing the development of a mass balance for each component. Finally, software was proposed to simulate PHB production and consumption of fatty acids using Cupriavidus necator. The software required continuity equations, material balance, and mass balance. This software, which contains the kinetic models, is a proposal for wastewater from edible oil industries.