Economic Optimizing Control for a U-loop Reactor

Marcus Krogh Nielsen: Sustainable protein production for a growing population

The industrial Ph.D project, Economic Optimizing Control for a U-loop Reactor, is a collaboration between Unibio A/S and DTU Compute, and is partially funded by The Danish Innovation Fund. Unibio A/S runs a carefully designed fermentation process, in which they can turn methane into protein.


For centuries now, the human population has been growing exponentially. Current predictions estimate that we will reach and plateau on over 11 billion people. Such a high population puts increasing demands on protein for consumption. The animal industry supplies us with a large portion of the portion we consume, but it is dependent on unsustainable sources, e.g., fishmeal. To meet the demand for protein in the animal industry, we must look to sustainable sources of protein for the meat industry. Unibio A/S provides on such sustainable alternative to fishmeal.


Uniprotein, the single-cell protein product produced by Unibio, is produced in a fermentation process using their patented U-loop technology. The process in illustrated in the image below. Fermentation provides a good alternative to unsustainable production of protein. However, the productivity of the fermentation is too low to make Uniprotein a financially viable alternative. Economic optimizing control for a U-loop reactor is an attempt to increase the productivity, and thus also the feasibility of Uniprotein as an alternative protein source for the meat industry.


Using the predictive properties of a mathematical model of the U-loop reactor, nonlinear state estimation and system identification algorithms, and efficient optimization algorithms, we design, implement and test a model-based control solution for the continuous bioprocess. Using this solution, the goal is to increase the productivity of the U-loop reactor from around 3 kg/m^3/hr to more than 6 kg/m^3/hr – increasing the productivity by more than 100%.


The successful completion of the project will mean that Unibio’s product can more effectively compete with the currently used unsustainable protein products, but also that we will have provided a sustainable and feasible protein product for the meat industry. The control system for a continuous bioprocess, which is the end-product of the project, can be much more widely used, and has great potential to increase productivity in a range of industries dependent on fermentation.

PhD project

By: Marcus Krogh Nielsen

Section: Scientific Computing

Principal supervisor: John Bagterp Jørgensen

Co-principal: Jakob Kjøbsted Huusom, Krist V. Gernaey, Ib Christensen, Jess Dragheim

Project title: Economic Optimizing Control for a U-loop Reactor

Term: 01/12/2019 → 01/03/2023


Marcus Krogh Nielsen
Industrial PhD
DTU Compute
+45 45 25 30 86


John Bagterp Jørgensen
DTU Compute
+45 45 25 30 88


Jakob Kjøbsted Huusom
Associate Professor
DTU Chemical Engineering
+45 45 25 28 01


Krist V. Gernaey
DTU Chemical Engineering
+45 45 25 29 70