24th January 2019


Scientists at Germany’s Ruhr-Universität Bochum (RUB) are researching a resource-efficient and sustainable approach to manufacturing chemicals. Dr. Robert Kourist (pictured at left), from the junior research group Mikrobielle Biotechnologie, and Dr. Marc Nowaczyk (right), the chair for Plant Biochemistry, have succeeded in genetically modifying cyanobacteria, creating cells that produce enzymes for the manufacture of basic and fine chemicals.

The bacteria also supply the energy required by the enzymes – by performing photosynthesis. A report on their work has been published in the journal Angewandte Chemie.

To function as biocatalysts, enzymes require chemical energy, which is typically supplied in the form of sugar or other high-energy bonds. The researchers from Bochum have taken advantage of the fact that, like plants, cyanobacteria perform photosynthesis.

“During photosynthesis, light energy is initially converted into chemical energy. In the second step, that energy is mainly used for binding of carbon dioxide. However, a small percentage of the energy remains and can be directly utilized,” said Nowaczyk. The approach adopted by the researchers is to decouple the supplied chemical energy from carbon fixation and to use it directly for chemical reactions.

Using genetically modified living cyanobacteria as catalysts for photosynthesis-driven biotransformations is a new approach. The researchers say they have observed that cyanobacteria catalyze only the synthesis of the desired chemical product in their experiments and, consequently, that they function selectively. Many catalytic processes produce not just one product, but also a mirrored one, which has to be filtered out.

“The outstanding selectivity is crucial for deployment in industrial applications,” said Kourist.

The experiments have also demonstrated that enzymes from other organisms can be successfully introduced into cyanobacteria. This means that the process can be used in a number of reactions.