GIULIETTI Ana Maria
congresos y reuniones científicas
Isolation of microorganism for biosurfactant production
FRANCO LIPORACE; OLIVERA JUAN; ANA MARIA GIULIETTI; CARLA QUEVEDO
Simposio; 16th International Biotechnology Symposium and Exhibition Biotechnology for the Development of a Green Economy; 2014
In this work hydrocarbon-degrading microorganisms were isolated from polluted soil and water samples obtained from a petroleum distillery located in Campana (Argentina). Isolation was performed by enrichment cultures in a mineral salt medium (MSM) containing a mixture of three different commercial fuels (HC) or polluted lagoon water (AgLag) as both carbon and energy source. The isolated strains were cultured in Erlenmeyer flasks containing MSM and HC in an orbital shaker. The ability of the isolated strains to produce biosurfactants was estimated by different methods: direct measurement of the surface tension; microplate assay and an emulsification capacity assay with four different organic phases. Seven of the isolated strains were able to reduce the surface tension of the culture media in more than 30%. Among these isolates, Ag.1.A-HC strain was cultured in a 3-liter stirred tank bioreactor (New Brunswick BioFlo 115). Biomass concentration and surface tension were evaluated during the process. A decrease in the surface tension value of the cell-free supernatant was observed. The initial and final values were 55,2mN/m ± 0,5mN/m and 32,5mN/m ± 0,2 mN/m respectively, and the highest cell concentration was found between day 6 and 8 of culture. According to these results the Ag.A.1 HC strain would have a potential use in both production of biosurfactant and bioremediation processes of hydrocarbon-polluted environments. Besides this, none of the tested strains showed good emulsifying capacity with the four organic phases which might suggest that the compound produced is a low molecular weight biosurfactant.