Generation of molecular hydrogen (H2) by microalgae and their biocatalysts

Abstract

Abstract Molecular hydrogen (H2) is a potent fuel and required for many industrial synthetic processes. To date, its large-scale production is highly energy-intensive and mostly based on fossil fuels. Biological H2 generation is widespread in nature and could alleviate many of the impacts associated with current H2 technologies. Several species of microalgae and cyanobacteria can produce H2 employing the process of photosynthesis, that is, they use light as the energy-source, and obtain the required electrons from water. Large-scale H2 production by algae requires specialized fermenters whose design needs expertise both in biology and process engineering. Cell-free or electrode systems employing the natural biocatalysts could be employed alternatively. Because H2 converting biocatalysts are specialized proteins mostly sensitive towards air, the implementation of cell-free systems on a large scale requires manufacturing and processing pipelines different from existing enzyme technologies.