|Biocatalytic production of white hydrogen from water using cyanobacteria
|Photosynthesis: Biotechnological applications with microalgae
|Bühler, K.; Bühler, B.; Klähn, S.; Krömer, J.O.; Dusny, C.; Schmid, A.
|Leipzig, Bibliothek, Hauptlesesaal, 00540032, 21-0242 DK: 620.95 Pho
Leipzig, Bibliothek, Hauptlesesaal, 00539975, 21-0247 DK: 620.95 Pho
|Hydrogen is an important building block in the chemical industry, but over the last decades, several attempts were also made to develop hydrogen as an energy carrier, for example, for fuel cell technology (electricity, mobility, heating). While this had limited success in the past, there is a renewed push for a systematic change to hydrogen as a major energy carrier. This shift is mainly driven by the widely accepted understanding that the observed harsh effects of climate change must be to a great deal connected to the burning of fossil energy carriers. We introduce a basic concept for producing hydrogen from water using natural photosynthesis applying the toolbox of white biotechnology. We term this “White hydrogen.” Water is split to electrons, protons and oxygen by photosystem 2 and hydrogen is subsequently formed. There are basically two approaches to achieve hydrogen formation, both using microbial whole cell biocatalysts. On the one hand, in biophotolysis, electrons liberated in the water oxidizing reaction are delivered via the photosystem(s) to a hydrogenase without a detour through central metabolism, but directly via a redox cofactor like NAD(P)H or ferredoxin. Oxygen is formed in the same cell as a by-product of the water splitting reaction and, as it is the case for hydrogen itself, must be separated. On the other hand, in biophotovoltaics, the photosynthetic electron transport chain is connected to a solid state electrode (anode), driving the reduction of protons to hydrogen on the cathode of a microbial electrolysis cell. Thereby, the formation of oxygen and hydrogen occurs in different reaction chambers, facilitating product recovery. While we expect the future energy mix to comprise bulk hydrogen produced in centralized facilities, for example, via electrolysis driven by electricity derived from photovoltaics or wind power plants, we believe that low-cost and less-resource-intensive solutions will make an important contribution in decentralized, autonomous facilities and applications. This could be smallscale production units for white hydrogen up to a few hundred kg per year that might be directly connected with hydrogen use after short-term storage circumventing complex logistics for large-scale transport and storage. For this purpose, continuous reaction formats are required, for example, the use of phototrophic biofilms as biocatalysts for the production of white hydrogen at biomass concentrations and light supply tuned for optimal hydrogen production efficiency. This chapter presents and discusses the frame, status, potential and challenges of these two approaches and proposes a concept for the integrated development of the molecular machinery, the biocatalysts and suitable reaction and process formats.
|Persistent UFZ Identifier
|Bühler, K., Bühler, B., Klähn, S., Krömer, J.O., Dusny, C., Schmid, A. (2021):
Biocatalytic production of white hydrogen from water using cyanobacteria
In: Rögner, M. (ed.)
Photosynthesis: Biotechnological applications with microalgae
De Gruyter, Berlin ; Boston, p. 279 - 306