Details

Autor(en) / Beteiligte

• Kuniyoshi, Taís M.
• Balan, Andrea
• Schenberg, Ana Clara G.
• Severino, Divinomar
• Hallenbeck, Patrick C.

Titel

Heterologous expression of proteorhodopsin enhances H2 production in Escherichia coli when endogenous Hyd-4 is overexpressed

Ist Teil von

• Journal of biotechnology, 2015-07, Vol.206, p.52-57

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2015

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• •Proton excess generated by proteorhodopsin does not increase H2 production by Hyd-3.•Proteorhodopsin (PR) enhances H2 production in Escherichia coli cells via Hyd-4.•The effect of PR expression in H2 production is light and retinal dependent. Proteorhodopsin (PR) is a light harvesting protein widely distributed among bacterioplankton that plays an integral energetic role in a new pathway of marine light capture. The conversion of light into chemical energy in non-chlorophyll-based bacterial systems could contribute to overcoming thermodynamic and metabolic constraints in biofuels production. In an attempt to improve biohydrogen production yields, H2 evolution catalyzed by endogenous hydrogenases, Hyd-3 and/or Hyd-4, was measured when recombinant proteorhodopsin (PR) was concomitantly expressed in Escherichia coli cells. Higher amounts of H2 were obtained with recombinant cells in a light and chromophore dependent manner. This effect was only observed when HyfR, the specific transcriptional activator of the hyf operon encoding Hyd-4 was overexpressed in E. coli, suggesting that an excess of protons generated by PR activity could increase hydrogen production by Hyd-4 but not by Hyd-3. Although many of the subunits of Hyd-3 and Hyd-4 are very similar, Hyd-4 possesses three additional proton-translocating NADH-ubiquinone oxidoreductase subunits, suggesting that it is dependent upon ΔμH+. Altogether, these results suggest that protons generated by proteorhodopsin in the periplasm can only enhance hydrogen production by hydrogenases with associated proton translocating subunits.