Biosurfactant, Bacillus subtilis, lipopeptides, antimicrobial activity / ProduÃÃo, extraÃÃo e caracterizaÃÃo de surfactante por Bacillus subtilis R14

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Lipopeptides represent a class of microbial surfactants with increasing scientific, therapeutic and biotechnological interests. The genus Bacillus is a producer of these active compounds, and among them B. subtilis produces surfactin, the most potent biosurfactant known. These compounds can act as antibiotics, antivirals, antitumorals, immunomudulators and enzyme inhibitors. In this work were evaluation production, extraction and characterization of biosurfactants obtained by cultivation of B. subtilis R14, as also microbiological activity and stability. During cultivation in defined medium, the surface tension of the medium was reduced from 54 mN/m in the beginning of the microbial growth to 30 mN/m after 20 h. A crude surfactant concentration of 2.0 g/L was obtained after 40 h of cultivation. A preliminary characterization suggested that two surfactants were produced, surfactin and iturin. The evaluation of the microbiological activity of these compounds was carried out against multidrugs-resistant bacteria strains of Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica. All strains were sensitive to the surfactants, in particular the Gram-positive Enterococcus faecalis. The lipopeptides produced showed that they are thermostable, stability for pH 4 to 8 and 20% of salinity. The results demonstrated that lipopeptides have a broad spectrum of actions and applications, including antimicrobial activity against microorganisms with multiresistant profiles

ASSUNTO(S)

biossurfactante, bacillus subtilis, lipopeptÃdios, atividade antimicrobiana farmacia

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