title: Exploiting algal NADPH oxidase for biophotovoltaic energy.
abstract: Photosynthetic microbes exhibit light-dependent electron export across the cell membrane, which can generate electricity in biological photovoltaic (BPV) devices. How electrons are exported remains to be determined; the identification of mechanisms would help selection or generation of photosynthetic microbes capable of enhanced electrical output. We show that plasma membrane NADPH oxidase activity is a significant component of light-dependent generation of electricity by the unicellular green alga Chlamydomonas reinhardtii. NADPH oxidases export electrons across the plasma membrane to form superoxide anion from oxygen. The C. reinhardtii mutant lacking the NADPH oxidase encoded by RBO1 is impaired in both extracellular superoxide anion production and current generation in a BPV device. Complementation with the wild-type gene restores both capacities, demonstrating the role of the enzyme in electron export. Monitoring light-dependent extracellular superoxide production with a colorimetric assay is shown to be an effective way of screening for electrogenic potential of candidate algal strains. The results show that algal NADPH oxidases are important for superoxide anion production and open avenues for optimizing the biological component of these devices.
authors: Department of Plant Sciences, University of Cambridge, Cambridge, UK.
authors: Alexander
authors: A
authors: Anderson
authors: Department of Plant Sciences, University of Cambridge, Cambridge, UK.
authors: Anuphon
authors: A
authors: Laohavisit
authors: Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA.
authors: Ian K
authors: IK
authors: Blaby
authors: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors: Paolo
authors: P
authors: Bombelli
authors: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors: Christopher J
authors: CJ
authors: Howe
authors: Institute for Genomics and Proteomics, UCLA, Los Angeles, CA, USA.
authors: Sabeeha S
authors: SS
authors: Merchant
authors: Department of Plant Sciences, University of Cambridge, Cambridge, UK.
authors: Julia M
authors: JM
authors: Davies
authors: Department of Plant Sciences, University of Cambridge, Cambridge, UK.
authors: Alison G
authors: AG
authors: Smith
mesh_terms: D056804:Biofuels; D016825:Chlamydomonas reinhardtii / Q000201:enzymology* / Q000528:radiation effects; D004560:Electricity; D005110:Extracellular Space / Q000378:metabolism; D005816:Genetic Complementation Test; D008027:Light; D019255:NADPH Oxidases / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D056804:Biofuels; D010940:Plant Proteins; D013481:Superoxides; D019255:NADPH Oxidases
keywords: Chlamydomonas; NADPH oxidase; alga; biophotovoltaic; energy
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