Hydrogen from blue-green algae: Research team solves key production problem

An international research team including the University of Kassel, Ruhr-Universität Bochum and Universidade Nova Lissabon has developed a new method for biological hydrogen production. Cyanobacteria – commonly known as blue-green algae – are capable of producing hydrogen via photosynthesis under certain conditions.

Oxygen inhibits hydrogen production

Until now, however, this approach faced a fundamental challenge: the oxygen inevitably generated during photosynthesis inhibits so-called hydrogenases – the enzymes responsible for the actual hydrogen production. Earlier approaches to removing oxygen either required the use of additional chemicals or were too inefficient for sustainable application.

Oxygen-free environment enables continuous cell activity

The researchers have now overcome this obstacle by embedding the bacteria in a special redox polymer deposited on an electrode. When an electric voltage is applied, the polymer selectively breaks down oxygen in the immediate vicinity of the cells. This creates an oxygen-free microenvironment in which the cells remain permanently active and can continuously produce hydrogen.

Outlook: Sunlight converted directly into hydrogen

The results open up a possible pathway to so-called biophotovoltaic systems – facilities that convert sunlight directly into hydrogen using living cells. Further development steps are required before the technology reaches technical maturity. The research was funded by the Federal Ministry of Education and Research and the Dietmar Hopp Foundation.