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Chlamydomonas reinhardtii cultures, deprived of inorganic sulfur, undergo dramatic changes during adaptation to the nutrient stress [Biotechnol. Bioeng. 78 (2002) 731]. When the capacity for Photosystem II (PSII) O(2) evolution decreases below that of respiration, the culture becomes anaerobic [Plant Physiol. 122 (2000) 127]. We demonstrate that (a) the(More)
The green alga, Chlamydomonas reinhardtii, is capable of sustained H(2) photoproduction when grown under sulfur-deprived conditions. This phenomenon is a result of the partial deactivation of photosynthetic O(2)-evolution activity in response to sulfur deprivation. At these reduced rates of water-oxidation, oxidative respiration under continuous(More)
Hydrogen uptake in the presence of various terminal electron acceptors was examined in Escherichia coli mutants synthesizing either hydrogenase 1 or hydrogenase 2. Both hydrogenases mediated nitrate-dependent H2 consumption but neither of them was coupled with nitrite. Unlike hydrogenase 2, hydrogenase 1 demonstrated poor activity with electron acceptors of(More)
Previous studies showed that, after 1.5–2 days of adaptation to inorganic S deprivation, the unicellular alga C. reinhardtii is capable of maintaining an intense hydrogen production for several days under actinic light illumination [3, 4]. As was demonstrated earlier, incubation of cells in S-deprived medium during the first 24 h results in a progressive(More)
The photosynthetic bacterium Rhodobacter capsulatus has been shown to regulate its nitrogenase by covalent modification via the reversible ADP-ribosylation of Fe protein in response to darkness or the addition of external NH4+. Here we demonstrate the presence of ADP-ribosylated Fe protein under a variety of steady-state growth conditions. We examined the(More)
The effect of light intensity on hydrogen production by sulfur-deprived Chlamydomonas reinhardtii was studied in situ using either long- or short-term experiments, or alternatively, with samples withdrawn from the photobioreactor. Overall hydrogen production by S-deprived culture was shown to depend on the light intensity and to exhibit regions of light(More)
Continuous photoproduction of H(2) by the green alga, Chlamydomonas reinhardtii, is observed after incubating the cultures for about a day in the absence of sulfate and in the presence of acetate. Sulfur deprivation causes the partial and reversible inactivation of photosynthetic O(2) evolution in algae, resulting in the light-induced establishment of(More)
The possibility of hydrogen production by a hydrogenase impaired mutant strain of Anabaena variabilis in outdoor culture was studied. A computer-controlled rooftop (outdoor) tubular photobioreactor (4.35 L) was assembled. H(2) production rates by A. variabilis PK84 grown in CO(2) + air in the photobioreactor were measured together with other parameters such(More)
The influence of (NH4)2SO4 concentration and dilution rate (D) on actual and potential H2 photoproduction has been studied in ammonium-limited chemostat cultures of Rhodobacter capsulatus B10. The actual H2 production in a photobioreactor was maximal (approx. 80 ml h−1 l−1) at D = 0.06 h−1 and 4 mM (NH4)2SO4. However, it was lower than the potential H2(More)
Hydrogen production by Anabaena variabilis ATCC 29413 and of its mutant PK84, grown in batch cultures, was studied in a photobioreactor. The highest volumetric H(2) production rates of native and mutant strains were found in cultures grown at gradually increased irradiation. The native strain evolved H(2) only under an argon atmosphere with the actual rate(More)