Advanced Kinetic Modeling of Bio-co-polymer Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Production Using Fructose and Propionate as Carbon Sources

Abstract

Biopolymers are a promising alternative to petroleum-based plastic raw materials. They are bio-based, non-toxic and degradable under environmental conditions. In addition to the homopolymer poly(3-hydroxybutyrate) (PHB), there are a number of co-polymers that have a broad range of applications and are easier to process in comparison to PHB. The most prominent representative from this group of bio-copolymers is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). In this article, we show a new kinetic model that describes the PHBV production from fructose and propionic acid in Cupriavidus necator (C. necator). The developed model is used to analyze the effects of process parameter variations such as the CO2 amount in the exhaust gas and the feed rate. The presented model is a valuable tool to improve the microbial PHBV production process. Due to the coupling of CO2 online measurements in the exhaust gas to the biomass production, the model has the potential to predict the composition and the current yield of PHBV in the ongoing process.

Multi-Rate Data Fusion for State and Parameter Estimation in (Bio-)Chemical Process Engineering

“…The second example is concerned with state estimation for microbial-based production of biopolymers in lab-scale setup. The underlying model was recently developed in our group with own experimental data [23].…”

“…However, the applied soft sensor concept could easily be extended to include reconstruction of both states from available measurements as depicted in Figure A1. Further information on the model itself is found in [23] and model parameters are summarized in Table A1.…”

“…To make bioplastics even more competitive, model approaches can be used to analyze, optimize and finally control the production in order to reduce the costs. In the following section, our recently developed PHBV production model based on online CO 2 exhaust gas measurements to capture biomass growth is described [23].…”

“…The nonlinear model was presented in [23] and describes the dynamics of a fed-batch process using fructose (c f ru ) and propionic acid (c p ) as carbon sources. Furthermore, the dynamics of the nitrogen source c n , residual biomass c res , HB-content c hb and HV-content c hv are accounted for.…”

“…The resulting model therefore comprises a system of six nonlinear ordinary differential equations as reported in the Appendix A. The parameter values and detailed description can be found in the original publication [23].…”