Andressa Decesaro

Produção de biossurfactantes por microrganismos isolados de solo contaminado com óleo diesel

The aim of this work was to produce biosurfactants through submerged fermentation using microorganisms isolated from soil contaminated with diesel. Microorganisms were isolated, characterized by the production of biosurfactants, and used to study the influence of type, induction and concentration of ammonium sulfate as a nitrogen source in the culture medium. The microorganisms that showed best results, in terms of production of biosurfactants, were identified as being of the genus Pseudomonas and Bacillus. The biosurfactants produced proved capable of reducing the surface tension of the media to 39 mN/m and 34 mN/m, respectively. Higher biosurfactant production was obtained in the medium containing 1% soybean oil without ammonium sulfate.

Bioremediation of Soil Contaminated with Diesel and Biodiesel Fuel Using Biostimulation with Microalgae Biomass

AbstractThis study evaluates the ability of biostimulation to enhance the bioremediation of soil contaminated with oily compounds as compared with natural attenuation. The soil was contaminated wit...

Biosurfactants during in situ bioremediation: factors that influence the production and challenges in evalution

Research on the influence of biosurfactants on the efficiency of in situ bioremediation of contaminated soil is continuously growing. Despite the constant progress in understanding the mechanisms involved in the effects of biosurfactants, there are still many factors that are not sufficiently elucidated. There is a lack of research on autochthonous or exogenous microbial metabolism when biostimulation or bioaugmentation is carried out to produce biosurfactants at contaminated sites. In addition, studies on the application of techniques that measure the biosurfactants produced in situ are needed. This is important because, although the positive influence of biosurfactants is often reported, there are also studies where no effect or negative effects have been observed. This review aimed to examine some studies on factors that can improve the production of biosurfactants in soils during in situ bioremediation. Moreover, this work reviews the methodologies that can be used for measuring the production of these biocomposts. We reviewed studies on the potential of biosurfactants to improve the bioremediation of hydrocarbons, as well as the limitations of methods for the production of these biomolecules by microorganisms in soil.

LIPÍDIOS MICROALGAIS COMO BIOSSURFACTANTES EM PROCESSO DE BIORREMEDIAÇÃO DE DIESEL E BIODIESEL EM SOLO

Nos ultimos anos tem crescido a preocupacao com o meio ambiente. Neste contexto incluem-se a busca de alternativas para a menor geracao de poluentes, bem como para descontaminacao de locais contaminados com residuos que podem ser toxicos ao meio ambiente e a populacao. O objetivo deste trabalho foi a utilizacao de lipidios microalgais como biossurfactantes, na descontaminacao de um solo contaminado com diesel ou biodiesel, comparando-se com a tecnica de atenuacao natural. Os lipidios foram extraidos da microalga Spirulina platensis e adicionados a solos contaminados com 4 % de diesel ou biodiesel. A biodegradacao foi acompanhada por determinacao de oleos e graxas e a atividade microbiana pela tecnica de evolucao de CO2. Os lipidios microalgais demonstraram sua potencial aplicacao na biorremediacao de residuos oleosos, uma vez que se obteve 81,9 % de biodegradacao do biodiesel e 81,7 % do diesel, bem maior quando comparada com 54,36 % e 30,09 % nos ensaios de atenuacao natural, com o contaminante diesel ou biodiesel respectivamente, em 60 dias de ensaio. A evolucao de CO2, tambem apresentou resultados elevados de CO2 acumulado nos ensaios adicionados do biossurfactante. No ensaio adicionado de biodiesel com biossurfactante, o acumulo de CO2 foi de 1.341,65 mg ao longo dos 60 dias, comparado com 775,3 mg de CO2 no ensaio com diesel e biossurfactante, enquanto que nos ensaios com a tecnica de atenuacao natural a evolucao de CO2 foi de 184,51 mg para diesel e 246,80 mg para biodiesel. Palavras-chave: Biodegradacao, Spirulina platensis, lipidios, evolucao de CO2. ABSTRACT The concern with the environment has been growing in last years. These contexts include the search for alternatives to low the generation of pollutants, as well as decontamination of sites contaminated with hazardous wastes that may be toxic to the environment and the population as a whole. The aim of this work was the use of microalgal lipids as biosurfactants in the decontamination of soil contaminated with diesel and biodiesel, compared with natural attenuation. Lipids were extracted of the Spirulina platensis biomass and added to diesel or biodiesel contaminated soils. The biodegradation was accompanied by determination of oil and grease and microbial activity by the technique of CO2 evolution. The microalgal lipids demonstrated its potential in the bioremediation of oil residues, since there was obtained 81.9% and 81.7% of biodiesel and diesel biodegradation respectively, greater than the values obtained in natural attenuation, of 54.36% and 30.09% with diesel or biodiesel respectively, at 60 days of bioremediation. The evolution of CO2 also showed high results of accumulated CO2 in the tests added of biosurfactant. In the assay of biodiesel added of biosurfactant, cumulative CO2 was 1341.65 mg at 60 days, compared to 775.3 mg of CO2 in assay realized with biosurfactant and diesel, while in trials with natural attenuation, the evolution of CO2 was 184.51 mg and 246.80 mg for diesel to biodiesel. Keywords: Biodegradation, Spirulina platensis, lipids; CO2 evolution.