Modeling the fermentation kinetics for poly(β-hydroxybutyrate) production by Bacillus megaterium BBST4

F.D. RAMOS; C.A. DELPINO; T. L. MOITINHO ALVES; M.A. VILLAR; M.S. DÍAZ

bahía Blanca

Congreso; IX Congreso Argentino de Ingeniería Química, CAIQ 2017; 2017

Asociación Argentina de Ingenieros Químicos (AAIQ)

Poly(β-hydroxybutyrate) (PHB), which belong to the family of poly(hydroxyalcanoate)s (PHAs), is considered a promising polymer not only because it can be produced from sustainable sources such as glycerol, a co-product in biodiesel production, but also for its mechanical properties and applications as packaging, carriers for drug deliv-ery and medical uses among others.In the last few years there has been a growing interest in the study of modeling biopol-ymer production from fermentation processes. In order to improve yield and productivity of biopolymers and reduce the production cost, several authors have proposed different models for batch and fed batch fermentations.Based on the approach presented above, the purpose of this work is to present a model considering the biopolymer production by means of Bacillus megaterium BBST4 isolated from superficial sediments of the Bahía Blanca estuary. We also perform a parameter esti-mation in order to adjust the implemented model to the experimental data to obtain reliable bioreaction kinetics. In this context, we look forward to concentrate our future research on developing valuables mathematical tools which could attend the different constraints of bi-opolymer production at higher scales.The mineral salt medium used in the experiments was the one suggested by Faccin et al., 2009. Glycerol (20 g/L) and urea (2.2 g/L) were the carbon and nitrogen source, respec-tively. The microorganisms were cultivated using an incubator shaker (New Brunswick Scien-tific, Excella E24) at an agitation rate of 250 rpm and 33 ºC [6] for 29 h in 1000 mL Erlen-meyer flasks with a 500 mL working volume. Several process variables were measured at dif-ferent time points using analytical methods, namely, total biomass, carbon source, nitrogen source, pH and biopolymer production.The fermentation process is represented by a differential-algebraic equations system. In order to obtain an appropriate representation, function and parameter estimation is formulated as a dynamic optimization problem, with a global approach, using orthogonal collocation over finite elements, in GAMS. We propose a mathematical model based on an adaptation of a differential-algebraic equations system. A satisfactory adjustment of the experimental data after parameter estima-tion, resulting in a model that can represent and quantitatively analyze the PHB production kinetics of a Bacillus megaterium BBST4 strain is obtained.