A simple kinetic model for growth and biosynthesis of polyhydroxyalkanoate in Bacillus flexus

Abstract

Polyhydroxyalkanoate (PHA), which is produced by several bacteria, is a biodegradable polymer that has many industrial and medical applications. This study deals with development of a simple kinetic model and modification of the logistic equation that can provide an adequate description of PHA formation process by Bacillus flexus. The parameters studied were kinetics of microbial growth, substrate consumption, and product formation. The microbial growth was described by simplification of Monod's model. A simplified Luedeking-Piret type model could be employed to represent the product kinetics. The kinetic constants were evaluated on the basis of non-linear regression and the differential equations were solved using Runge-Kutta algorithm and MATLAB software. A good agreement was found between the experimental and predicted values, which indicated that the model differential equations could describe the PHA formation and fermentation process. In this study, a modification of the logistic equation has also been attempted for describing the growth of B. flexus.

Strategies for Large-scale Production of Polyhydroxyalkanoates

“…In addition to development of mathematical models for Azohydromonas sp., at least in one paper, a simple kinetic model based on Leudeking-Piret expression was used to represent PHA production kinetics by Bacillus flexus. 91 Model parameters were found by non-linear regression technique, and a good agreement was found between model predictions and experimental observations. The developed model could be further used to design high cell density fermentations involving Bacillus sp.…”

Utilization of waste engine oil by Ochrobactrum pseudintermedium strain C1 that secretes an exopolysaccharide as a bioemulsifier

“…The most active part of the cell growth curve is the exponential (log) phase, which is used for the determination of different kinetic parameters (Divyashree et al, 2009). The growth kinetics of O. pseudintermedium sp.…”

Correlación del Crecimiento de Pseudomonas fluorescens en la Producción de Polihidroxialcanoatos de Cadena Media (PHA MCL) mediante Modelos Primarios de Gompertz, Logístico y Baranyi

“…Se observa una máxima concentración de biomasa de 0,4647 g/L, cuando la disminución de azúcares alcanza un valor mínimo de 0,019 g/L y la concentración de amonio disminuye hasta 0.12 mg/L; estos valores se obtienen al inicio de la fase estacionaria fase de inicio de la producción o acumulación de polihidroxialcanoatos como metabolito secundario. Estos resultados concuerdan los valores presentados por Divyashree et al, 2009 donde el incremento en la concentración de biomasa refleja una disminución de la concentración de nitrógeno y presenta una velocidad máxima de síntesis de PHA.…”

“…Los modelos cinéticos facilitan el análisis de datos y proporcionan estrategias para resolver problemas presentes en los procesos de fermentación; información que es potencialmente valiosa para la mejora del rendimiento del proceso por lotes. Rendimientos de productos finales y conversiones de sustrato son criterios con efecto sobre la productividad (Divyashree et al, 2009). …”