RESUMEN
The application of seawater for bacterial fermentative production is a cost-effective technology. Hydrogen production by marine photosynthetic bacterium with seawater failed to continue after more than 10 days, and was accompanied by the formation of hydrogen sulfide and a change in culture color from red to black. However, substrate consumption in the blackish culture was comparable to that in a hydrogen-producing culture. A decrease in hydrogen production occurred upon the addition of sodium sulfide at concentrations of 1.5 mM or higher. PCR analysis targeted at the 16S rDNA sequence selective for sulfate-reducing bacteria revealed the existence of sulfate-reducing bacteria in inoculation cultures of the phototrophic bacterium and medium for hydrogen production. Hence, the high sulfate concentration of seawater, the low oxidation-reduction potential under hydrogen-producing conditions, and the presence of electron donors such as acetate might promote the metabolic activities of sulfate-reducing bacteria, resulting in the deterioration of hydrogen production with seawater.
Asunto(s)
Hidrógeno/metabolismo , Rhodobacter/metabolismo , Agua de Mar/microbiología , Bacterias Reductoras del Azufre/crecimiento & desarrollo , Reactores Biológicos , ADN Ribosómico/genética , Relación Dosis-Respuesta a Droga , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , Rhodobacter/efectos de los fármacos , Rhodobacter/crecimiento & desarrollo , Agua de Mar/química , Sulfatos/metabolismo , Sulfuros/metabolismo , Sulfuros/farmacología , Bacterias Reductoras del Azufre/genética , Bacterias Reductoras del Azufre/metabolismo , Microbiología del AguaRESUMEN
In photosynthetic bacteria, after transition to light-anaerobic and nitrogen-deficient conditions, hydrogen evolution starts with expression of nitrogenase activity. Until the expression of enough activity, Rhodovulum sulfidophilum consumed substrates and converted them to poly(3-hydroxybutyrate) (PHB), resulting in a decrease in the proportion of substrate converted into hydrogen gas. To prevent conversion to PHB during the period when nitrogenase activity is derepressed, the authors employed a cultivation method consisting of three stages: cell growth, nitrogenase derepression, and hydrogen production. Cells cultivated by this method exhibited no lag time before the commencement of hydrogen evolution and gave an improved yield of hydrogen from the algal fermentative products.
RESUMEN
Growth and lipid production of microalgae were investigated, with attention to the feasibility of making use of flue gas CO2 as a carbon source. The effect of a high CO2 level in artificial seawater differed from strain to strain. Three algal strains from the Solar Energy Research Institute (Golden, CO) collection were selected as good fixers of CO2 when the level of CO2 in the sparging gas was high. These algae also accumulated large amounts of crude lipids. SOx and NOx inhibited algal growth, but a green alga, Nannochloris sp. NANNO2 grew after a lag period, even when it received NO gas at the concentration of 300 ppm.
Asunto(s)
Dióxido de Carbono/metabolismo , Chlorophyta/crecimiento & desarrollo , Eucariontes/crecimiento & desarrollo , Depuradores de Gas , Óxido Nítrico/farmacología , Óxido Nitroso/farmacología , Óxidos de Azufre/farmacología , Biodegradación Ambiental , Biotecnología/instrumentación , Biotecnología/métodos , Chlorophyta/efectos de los fármacos , Chlorophyta/metabolismo , Eucariontes/efectos de los fármacos , Eucariontes/metabolismoRESUMEN
A 47-year-old male was admitted because of persistent jaundice. Akiyami C disease was diagnosed by serological tests using the microscopic agglutination tests. The source was considered to be a water contaminated with leptospiras which he had drunk while working at a civil engineering job. The reported cases of Akiyami C disease have recently decreased and this is the 6th case reported in the last 15 years.
