Systems Theory and Automatic Control

Development of a model-based state observer for monitoring the production of biopolymers in Ralstonia eutropha



The bioplastic polyhydroxybutyrate (PHB) is an energy storage compound produced by the bacteria Ralstonia eutropha under carbon excess or unbalanced growth conditions, e.g. lack of essential nutrients.

In short


Biopolymers (PHAs) are highly promising for the transformation of the global economy away from its dependence on fossil raw materials to a sustainable bio-based economy. So far, the industrial use of biopolymers is limited by their non-competitive production costs.

Model-based development and operation of a sustainable biotechnological processes could be the key for the competitive production of PHB as it allows to use a combination of varying feed stocks obtained from waste materials and renewable resources .

Hybrid cybernetic modelling (MHE) allows a detailed description of the system taking the metabolism of the organism in form of elementary modes, the dynamics of the process in form of ODEs, and information about cellular regulation, through the introduction of cybernetic variables, into account.

The goals of this master's thesis are:

  • Extending the HCM, by reconstructing the metabolic network and applying techniques from metabolic pathway analysis.
  • Design of the state observer, which allows the estimation of the PHB content, based on the available online measurements.
  • Testing the HCM-based state observer using real data.

Topic Area:

Modelling, estimation, control of uncertain biotechnological processes

Required Prerequisites:

Interests: Modelling, Simulation, State Estimation
Experience with: programming in MATLAB, python, C++
Language: German or English