Photosynthetic electron partitioning between [FeFe]-hydrogenase and ferredoxin:NADP+-oxidoreductase (FNR) enzymes in vitro

• Main Authors: Yacoby, Iftach (Contributor), Pochekailov, Sergii (Contributor), Zhang, Shuguang (Contributor), Toporik, Hila (Author), Ghirardi, Maria L. (Author), King, Paul W. (Author)
• Other Authors: Massachusetts Institute of Technology. Center for Biomedical Engineering (Contributor), Massachusetts Institute of Technology. Department of Chemical Engineering (Contributor)
• Format: Article
• Language: English
• Published: Proceedings of the National Academy of Sciences (PNAS), 2012-02-02T20:06:35Z.
• Subjects: Article
• Online Access: Get fulltext

 Photosynthetic water splitting, coupled to hydrogenase-catalyzed hydrogen production, is considered a promising clean, renewable source of energy. It is widely accepted that the oxygen sensitivity of hydrogen production, combined with competition between hydrogenases and NADPH-dependent carbon dioxide fixation are the main limitations for its commercialization. Here we provide evidence that, under the anaerobic conditions that support hydrogen production, there is a significant loss of photosynthetic electrons toward NADPH production in vitro. To elucidate the basis for competition, we bioengineered a ferredoxin-hydrogenase fusion and characterized hydrogen production kinetics in the presence of Fd, ferredoxin:NADP+-oxidoreductase (FNR), and NADP+. Replacing the hydrogenase with a ferredoxin-hydrogenase fusion switched the bias of electron transfer from FNR to hydrogenase and resulted in an increased rate of hydrogen photoproduction. These results suggest a new direction for improvement of biohydrogen production and a means to further resolve the mechanisms that control partitioning of photosynthetic electron transport.