Robust bioprocesses



Participating researchers
Carl Johan Franzén, Associate Professor
Valeria Mapelli, Project Leader
David Nickel, PhD student
Helén Olsson, Research Engineer
Lisbeth Olsson, Professor, Head of Division
Julia Paraskova, Research Engineer
Anna Sandersen, Industrial PhD Student
Ruifei Wang, PhD Student
Like any industrial process, industrial biotechnology processes must run consistently with high yield, productivity and energy efficiency. This holds true for all sectors of industrial biotechnology, e.g. production of food ingredients, pharmaceuticals and nutraceuticals, biofuels and chemicals. The tricky thing is that we deal with living catalysts – cells which may change characteristics as they adapt to stressful situations that arise in the bioreactor or during downstream processing. We also deal with complex and variable raw materials such as lignocellulosic residues from agriculture and forestry. Moreover, the overall objective of the cells – to multiply – is usually not the same as our objective in a production process: to obtain the desired product in high amounts.
In production of e.g. baker’s yeast and lactic acid bacteria starter cultures, the product is the cells themselves. In this case, the process must stimulate the cells such that they maintain the desired properties, i.e. biochemical activities, even after downstream processing like freezing or freeze drying, and after storage. We use physiologically based control of feed rates to the bioreactor and perturbations to the medium composition to promote production of cells in a desired physiological state.
To obtain robust bioprocesses, the enzymes and microorganisms that are used must withstand variations in e.g. availability of nutrients, pH, temperature and pressure. Enzymes and cells must also cope with inhibitors that may be present in the bioreactor. This requires not only specialised cell factories, but also bioprocesses that are designed to maximise the potential of the cell factory. For example, the process must be designed so that cells do not enter into unproductive physiological states, such as dormancy or sporulation. A basic requirement in connection to this is to enable well-stirred conditions even when using fibrous renewable raw materials, such as wheat straw or spruce chips. This also allows us to control the concentrations of sugars and inhibitors at levels that enable hydrolysis of polysaccharides and fermentation of the sugars as completely as possible.
We run projects in the following areas:


  • Development of processes for production of robust starter cultures of lactic acid bacteria
  • Lactic acid production from lignocellulosic raw materials
  • Multi-feed Simultaneous Sacharification and Fermentation for high gravity lignocellulosic fermentation processes
  • Design of the yeast propagation stage to promote inhibitor tolerance and xylose fermentation
  • Process integration to optimise industrial bioprocesses


Please follow the links below to read more about the projects

Right now, we focus on lactic acid bacteria and bioethanol. The projects will lead to improvements in these specific processes. The projects will also lead to general knowledge on biobased processes, which can be applied to the production of many other products in the context of the biorefinery.  

Researchers: Bettina Lorantfy, Valeria Mapelli, Carl Johan Franzén, Lisbeth Olsson

The aim of this project is to investigate how different culture conditions; anaerobic, aerobic, and respiratory of lactic acid bacteria influence the robustness of the cells.
Researchers: Anna Sandersen, Carl Johan Franzén, Lisbeth Olsson

The aim of this project is to identify the mechanisms that lead to cellular robustness of L. lactis for optimization of the production process of starter cultures.

Bacillus coagulans as microbial cell factory for L-lactic acid production from agricultural and forestry waste
Researchers: Martina Aulitto, Patrizia Contursi and Simonetta Bartoulucci (Univ of Naples Frederico II), Salvatore Fusco, and Carl Johan Franzén

This project aims at developing fermentation technology using the thermophilic bacterium Bacillus coagulans as a microbial cell factory for the production of L-lactic acid from lignocellulosic biomass.

Researchers: David NickelRuifei Wang, Johan Westman, Carl Johan Franzén

In the multifeed SSF approach we address issues like high solids loading and high concentration of inhibitors by controlled feeding of solid materials, yeast cells and enzymes.
Bottlenecks in lignocellulosic ethanol production: xylose fermentation and cell propagation
Researchers: Marlous van Dijk, Mats Galbe and Ola Wallberg (Lund University), Rakesh Koppram (Taurus Energy AB), Lisbeth Olsson

In this project we investigate how adaptation during the integrated propagation can improve the xylose productivity and inhibitor tolerance of Saccharomyces cerevisiae strains during 2nd generation bioethanol production.

Researchers: Rickard Fornell (SP Technical Research Institute of Sweden), Ruifei WangDavid NickelLisbeth Olsson, Carl Johan Franzén

In this collaborative process integration project, we study the possibilities and potential configurations for water and heat recirculation in the multi-feed SSF process, and biogas production from the residual streams from the process.

Published: Fri 05 Jun 2015. Modified: Thu 08 Dec 2016