RESUMO
Background: Modeling the kinetics of the biodesulphurization bioprocess for the refining of pyrite ash by Saccharomyces cerevisiae and Acetobacter aceti have been studied in batch-type liquid- state bioreactors. Results: The biodesulphurization experiments were performed at varying temperatures of 25ºC, 30ºC and 35ºC for eight weeks. Glucose, acetic acid and ethyl alcohol were used in the incubation media as substrates and acid sources. pH and oxidation reduction potential (ORP) observations have been determined weekly and the dissolved sulphur was measured at the end of the eight weeks trials. An equation calculating pH was derived from the iron oxidation reaction containing the ferric to ferrous iron [Fe+3/Fe+2] ratio as a variable. The Michaelis-Menten predictive specific growth rates (qFe+2), which were estimated from pH and ORP observations, were compared by plotting [qFe+²]pH vs. [qFe+2]mV. The highest ratio of dissolved sulphur over total sulphur (Sd/St) was found to be 0.5 in the biodesulphurization processes. Conclusions: The model provides predictions of ferric to ferrous iron rates and specific growth rates [qFe+²]pH vs. [qFe+2]mV and can be used for the determination of oxidized and reduced ions. The ratios of dissolved sulphur to total sulphur (Sd/St) have shown some promising results for S. cerevisiae to be used as a biodesulphurization and refining microorganism for pyrite ash and the other sulphide minerals.
Assuntos
Saccharomyces cerevisiae/metabolismo , Enxofre/metabolismo , Acetobacter/metabolismo , Sulfetos , Biodegradação Ambiental , Cinética , Cinzas , Reatores Biológicos , Dessulfurização , Ferro , Modelos BiológicosRESUMO
Se presenta a continuación una revisión documental relacionada con los aspectos de mayor interés en la desulfuración bacteriana de combustibles fósiles. Específicamente se desarrolló una investigación en cuanto al marco general y justificación de esta técnica, las rutas degradativas elucidadas hasta ahora, los microorganismos desulfuradores involucrados, elementos claves en el desarrollo de la desulfuración bacteriana, algunas áreas de progreso y tendencias futuras.
A documental review related to the central aspects of the fossil fuel biodesulfurization is presented. Specifically, the investigation includes developments with respect to the general framework and justification of the technique, degradative pathways elucidated up to now, the microorganisms involved, applications, areas in progress and future trends.
