Produção de biossurfactantes por Bacillus spp. em condição anaeróbia

• Autor(a) principal: Fernandes, Péricles Leonardo
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5292
• topic: Biossurfactantes; Bacillus spp.; Anaerobiose; Biosurfactants; Bacillus spp.; Anaerobiosis; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA::MICROBIOLOGIA APLICADA

The objective of the present study was to determine the nutritional and redox conditions that promote the growth and biosurfactant production by Bacillus spp.. Three strains belonging to the culture collection of the Laboratório de Biotecnologia e Biodiversidade para o Meio Ambiente (LBBMA), previously evaluated for their potential for application in Microbial Enhanced Oil Recovery, including biosurfactant production, were used in the study. Among the three strains, only LBBMA111A was able to grow in mineral medium reduced with 0,5 mmol L-1 of dithiothreitol in the absence of any growth factor. Strains LBBMA155 and LBBMA283 required supplementation of the growth medium with DNA at low redox potential. However, this behavior can be modified according to the physiological state of the cells. The redox potential was shown to affect the growth patter of all strains, but in different intensities. In addition, the redox potential of the growth media also affected the yield and activity of biosurfactants produced by all strains. The growth of the strains was affected by the carbon and nitrogen sources of the media. The three strains were not able to growth when starch or pyruvate were used as carbon source. Either the carbon source or the nitrogen source of the media affected the production of biosurfactants. The greatest growth and biosurfactant production was observed when proteose peptone was used as the nitrogen source. The greatest growth was obtained when sucrose was the carbon source; however, for strains LBBMA111A and LBBMA283, glucose provided the greatest reduction of the interfacial tension. Variations in carbon and nitrogen sources appear to affect the structure of the biosurfactants produced. It is concluded that the three strains Bacillus are potential candidates for Microbial enhanced oil recovery (MEOR) based on the production of biosurfactants in situ; nevertheless, more studies must be conduct to evaluate the range of physical- chemical conditions for their successful application.