Don't change the bioreactor, but the microorganism

Food companies produce amino acids, oils, and proteins in large bioreactors using microorganisms that grow on sugars and oxygen. The challenge is creating a stable growth environment for microorganisms inside the reactor, but this is difficult. Ruud Weusthuis, Professor of Microbial Biotechnology at WUR, wondered: what if we reverse this and adapt the microorganisms to the conditions? He is now investigating this in an NWO project.

Weusthuis is collaborating in a public-private project with researchers from Delft and Groningen, and companies dsm-firmenich (food and health ingredients) and Evonik (chemicals). The participating companies are familiar with the challenges of microbial production of food ingredients. They produce dozens of products using microorganisms, adding sugars and oxygen, but rarely achieve ideal conditions in large bioreactors. Usually, the oxygen concentration is too high at the bottom and too low at the top, while the sugar concentration depends on the distance from a feeding point. This impedes the growth, production, and quality of microorganisms. Despite stirring and aerating the reactor, conditions remain suboptimal.

Weusthuis proposes a completely new approach: don’t change the bioreactor, but the microorganism. 'I want to adapt microorganisms so that they specifically respond to varying oxygen and sugar concentrations, thereby eliminating the differences.' How he intends to do this, he doesn't reveal. 'This process has not been described previously in literature and could lead to a patent application.'

What he can reveal is that the research will focus on baker’s yeast and the bacterium E. coli. He plans to genetically modify these microorganisms to produce proteins that better handle varying sugar and oxygen concentrations. As a result, the yeast and bacteria could potentially produce more products at a faster rate in a bioreactor, if the experiment is successful.

Three research groups are involved in this NWO project. Weusthuis, together with his colleague Mark Bisschops, will focus on researching the microorganisms. They will jointly hire a PhD student. Max Fürst from the University of Groningen will work with a PhD student on protein design. Cees Haringa from TU Delft will conduct bioreactor research with a new postdoc. NWO is contributing €900,000 from the Open Technology Programme. Participating companies co-finance the research and provide testing facilities and expertise.

Weusthuis: 'This is a new and bold idea, so we have extensively discussed the necessary knowledge and expertise required for its development. We are now finalising the consortium agreement. After that, we will hire the two PhD students and the postdoc. I expect we’ll start the research in October or November.'

• Courses at BSc and MSc study programmes of Biotechnology, Biobased Science and Food Technology