title: H2 production in Rhodopseudomonas palustris as a way to cope with high light intensities.
abstract: The ability of coping with the damaging effects of high light intensity represents an essential issue when purple non-sulfur bacteria (PNSB) are grown under direct sunlight for photobiological hydrogen production. This study was aimed at investigating whether H2 photo-evolution could represent, for Rhodopseudomonas palustris 42OL, a safety valve to dissipate an excess of reducing power generated under high light intensities. The physiological status of this strain was assessed under anaerobic (AnG) and aerobic (AG) growing conditions and under H2-producing (HP) conditions at low and high light intensities. The results obtained clearly showed that Fv/Fm ratio was significantly affected by the light intensity under which R. palustris 42OL cells were grown, under either AnG or AG conditions, while, under HP, it constantly remained at its highest value. The increase in light intensity significantly increased the H2 production rate, which showed a positive correlation with the maximum electron transfer rate (rETRmax). These findings are important for optimization of hydrogen production by PNSB under solar light.
authors.affiliation: Department of Agrifood Production and Environmental Sciences, University of Florence, Piazzale Delle Cascine 24, I 50144, Florence, Italy. Electronic address: dayanaisabel.muzziottigil@unifi.it.
authors.forename: Dayana
authors.initials: D
authors.lastname: Muzziotti
authors.affiliation: Department of Agrifood Production and Environmental Sciences, University of Florence, Piazzale Delle Cascine 24, I 50144, Florence, Italy; Institute of Chemistry of Organometallic Compounds (ICCOM), CNR, Via Madonna del Piano, 10, 50019, Sesto Fiorentino, Florence, Italy. Electronic address: alessandra.adessi@unifi.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Adessi
authors.affiliation: Institute of Ecosystem Study (ISE), CNR, Via Madonna del Piano, 10, 50019, Sesto Fiorentino, Florence, Italy. Electronic address: faraloni@ise.cnr.it.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Faraloni
authors.affiliation: Institute of Ecosystem Study (ISE), CNR, Via Madonna del Piano, 10, 50019, Sesto Fiorentino, Florence, Italy. Electronic address: torzillo@ise.cnr.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Torzillo
authors.affiliation: Department of Agrifood Production and Environmental Sciences, University of Florence, Piazzale Delle Cascine 24, I 50144, Florence, Italy; Institute of Chemistry of Organometallic Compounds (ICCOM), CNR, Via Madonna del Piano, 10, 50019, Sesto Fiorentino, Florence, Italy. Electronic address: roberto.dephilippis@unifi.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: De Philippis
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D004579:Electron Transport; D006859:Hydrogen / Q000378:metabolism*; D008027:Light; D010714:Phosphatidylethanolamines; D012241:Rhodopseudomonas / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects*
chemical_list: D010714:Phosphatidylethanolamines; D006859:Hydrogen; C047813:N-succinyl-1,2-dioleoylphosphatidylethanolamine
keywords: Aerobic growth conditions; Anaerobic growth conditions; Excess reducing power; H(2)-producing conditions; Photo-acclimation; Photosynthetic quantum yield