Production and characterization of biosurfactants aiming at the industrial and biorremediation processes application.
Screening for the best biosurfactant-producing microorganism was carried out using 48 microorganisms, 5 bacteria, 11 yeasts, 27 filamentous fungi (deuteromycetes) and 5 basidiomycetes, from the Amazon Area and from the Culture Collection of the Systematic and Microbial Physiology Laboratory/FEA/UNICAMP. The microorganisms were cultivated in media with diesel oil 10% (v/v). Planococcus citreus was selected from the 48 microorganisms. Biosurfactant was isolated from the culture broth and lyophilized. Depending on the isolation method, extraction with chloroform and methanol or precipitation with ammonium sulfate, a biosurfactant presenting good oil in water (B9) or water in oil (B9S) emulsification, respectively, was obtained. Biosurfactant B9 was obtained at the concentration 0.28 g/L and B9S at 0.11 g/L. When the biosurfactants were produced in a fermenter for 72 h the concentration of the biosurfactant B9 was 0.53 g/L and of B9S 0.031 g/L. Biosurfactant B9 reduced the water surface tension to 37 mN/m (5 g/L), but in this condition it also presented a phytotoxic effect. B9S presented excellent emulsification activity at low concentration (0.2 g/L) and without showing a phytotoxic effect. These two fractions were characterized by ESI (+)?MS using a mass espectrometer, FT-IR and Nuclear Magnetic Resonance. In each one of these fractions a mixture of 10 oligomers, with a variation in masses from 502 to 899 was found. No antimicrobial activity against Gram-positive and Gram-negative bacteria, yeast and filamentous fungi, was produced by either of these fractions. P. citreus showed satisfactory growth and the production of surface-active compounds when cultivated in industrial frying-oil wastes, but with an increase in the required production time (96h). Biosurfactant B9 presented the same characteristics of reduction in superficial tension, emulsification activity and phytotoxicity over a twelve-month storage period.
Advisor:Lucia Regina Durrant; Lucia Regina Durrant [Orientador]; Marta Cristina Teixeira Duarte; Alexandre Nunes Ponezzi; Ranulfo Monte Alegre; Hamilton Roberto Fortes Bavutti; Jose Luiz Pereira; Fumio Yokoya
School:Universidade Estadual de Campinas
Source Type:Master's Thesis
Date of Publication:09/27/2004