Paul F. Weaver

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Thirty-three strains of Rhodopseudomonas capsulata have been studied in order to develop a more comprehensive characterization of the species. On the basis of morphological, nutritional, physiological and other properties, the characteristics of an “ideal biotype” have been defined, which can be used to distinguish Rps. capsulata from similar purple(More)
Thirty-three wild type strains of Rhodopseudomonas capsulata were examined for ability to engage in genetic recombination through mediation by “gene transfer agent” (GTA) particles. The genetic exchange assays were based on capacity of strains to produce or receive GTA required for restoration of photosynthetic growth competence to a non-photosynthetic(More)
A hydrogenase linked to the carbon monoxide oxidation pathway in Rubrivivax gelatinosus displays tolerance to O2. When either whole-cell or membrane-free partially purified hydrogenase was stirred in full air (21% O2, 79% N2), its H2 evolution activity exhibited a half-life of 20 or 6 h, respectively, as determined by an anaerobic assay using reduced methyl(More)
Rhodospirillum rubrum and Rhodopseudomonas capsulata were able to grow anaerobically in the dark either by a strict mixed-acid fermentation of sugars or, in the presence of an appropriate electron acceptor, by an energy-linked anaerobic respiration. Both species fermented fructose without the addition of accessory oxidants, but required the initial presence(More)
When photosynthetic bacteria Rhodocyclus gelatinosus and Rhodospirillum rubrum were cultured with CO in the gas phase, a CO-linked pathway was quickly induced. These bacteria perform a water-gas shift reaction with CO and H2O, and produce H2 and CO2 in nearly stoichiometric quantities. The hydrogenase, a terminal enzyme of the linked pathway, is extremely(More)
Spiral tubular bioreactors were constructed out of transparent PVC tubing for H2 production applications. Both a cyanobacterial Anabaena variabilis mutant that lacks uptake hydrogenase activity and the photosynthetic bacterium Rhodobacter sp. CBS were tested in the bioreactors. Continuous H2 photoproduction at an average rate of 19 mL min-2.h-1 was observed(More)
Rhodospirillum rubrum was shown to grow fermentatively on fructose with N2 as a nitrogen source. The nitrogenase activity of these cells was regulated by the NH4+ switch-off/switch-on mechanism in a manner identical to that for photosynthetically grown cells. In vitro, the inactive nitrogenase Fe protein from fermenting cells was reactivated by an(More)
Two types of laboratory-scale bioreactors were designed for H(2) production by purple nonsulfur bacteria. The bioreactors employed a unique type of hydrogenase activity found in some photosynthetic bacteria that functions in darkness to shift CO (and H2O) into H(2) (and CO2). The mass transport of gaseous CO into an aqueous bacterial suspension was the(More)
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