Agentes inibidores da atividade metabólica e do processo de adesão de Desulfotomaculum nigrificans em superfície de aço inoxidável

• Autor(a) principal: Leão, Bruna Almeida
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5313
• topic: Bactéria redutora de sulfato; Agentes inibidores; Sulphate reducing bacteria; Agents inhibition; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA::MICROBIOLOGIA APLICADA

The sulphate reducing bacteria (SRB) are considered the principal group of microorganisms involved in the formation of biofilms and biocorrosion of pipelines. The prevention and the control of the growth of that bacterial group have been accomplished mainly by the use of biocide or bacteriostatic agents, as well as for the use of metabolic inhibitors. In this work the effect of mixtures was evaluated containing the biosurfactant rhamnolipid, the inhibitor metabolic molybdate of sodium and the biocide tetrakis (hydroxymethyl) phosphonium sulfate (THPS) about the metabolic activity of Desulfotomaculum nigrificans as well as about your adhesion to coupons of stainless steel AISI 304. The effect of the mixtures about the metabolic activity was evaluated by the estimate of viable cells and for the determination of residual sulphate in the medium of culture. The evaluation of the adhesion to coupons of stainless steel was accomplished by the direct count to the epifluorescence microscope. The experimental planning was accomplished according to Central Design Compost Rotational (DCCR) and the Methodology of Surface of Answer (MSR) was used to analyze the experimental design. There was not significant difference among the effects caused by the three compounds in the cellular viability in 6 and 18 hours after the addition of the compounds to the culture of D. nigrificans. All the appraised compounds were capable to inhibit the growth of D. nigrificans in anaerobic medium Baars to 55 ºC. The data of concentration of residual sulphate confirmed the effect of inhibition of the compounds also tested about the metabolic activity of that bacterium. Among the appraised compounds, the biosurfactant rhamnolipid was what presented larger effect of inhibitation in the adhesion of D. nigrificans to coupons of stainless steel, when cultivated in medium Baars to 55 ºC. It was the only compounds with effect significant statistics appeared in the times of 24, 48 and 96 hours of treatment evaluated. The Methodology of Surface of Answer revealed that the largest inhibition of the adhesion happens when the biosurfactant is added in concentrations from 1,0 to 1,6 times the value of your concentration critical micelar. The results suggest the potential of application of the biosurfactant rhamnolipid in the control of the adhesion and, eventually, of the biocorrosion caused by D. nigrificans.