Anais do Congresso Paranaense de Microbiologia
Anais do III Congresso Paranaense de Microbiologia

Sophorolipids are the most promising and attractive biosurfactant and one of the main recent approaches is its antimicrobial action against Gram-positive and Gram-negative bacteria. Antimicrobial activity of sophorolipids is due the mechanism of changes or rupture in the cellular membrane, inducing the outpouring of their cytoplasmic contents and the consequent death of the pathogen. These surfactants can be used as an alternative for the substitution of conventional drugs. The antimicrobial activity of sophorolipids depends on several factors, such as the producer microorganism, conditions of fermentation and the chemical structure of the molecule. Sophorolipids are extracellular glycolipids, produced mainly by yeast Candida bombicola, composed of a disaccharide sophorose (O β-D-glucopyranosyl-2-1-β-D-glucopyranose) linked by a glycosidic bound to the terminal or sub-terminal carbon of a fatty acid chain. Because of these structural characteristics, sophorolipids have been reported with several applications, which are directly related to the predominance of their acidic and lactonic forms. Food from animal origin, in specially chicken meat, are responsible for dissemination of microorganisms that cause food poisoning. Therefore, the aim of this study was to investigate the antimicrobial activity of sophorolipids from Candida bombicola ATCC 22214 using oleic acid (C18:1) as hydrophobic source in the production. The fermentations were carried in 1 L Erlenmeyer flasks, containing 100 mL of the media (g L-1): 77.5 of glucose, 2.5 of yeast extract and 75 of oleic acid, 288 h at 30º C and 150 rpm. Sophorolipids were obtained by extraction of the supernatant and separated by liquid-liquid extraction using hexane, methanol and ethyl acetate. The investigation of the antimicrobial activities in water wash chicken meat consisted in immersing of 100 g of cubes of chicken meat in a solution containing water with sophorolipid. The test was performed in triplicate in three different concentration (500, 2,250 and 4,000 μg / mL). It was used as standard test, immersion in chlorinated potable water (1 ppm chlorine). After each test, the immersion water was stored in sterile plastic bags and kept under refrigeration. Microbiological analyzes were conducted using Petrifilms (3M) plates for visualization and determination of the mesophilic aerobes microbial reduction. The activity of sophorolipids from C. bombicola against mesophilic aerobes was effective and presented a reduction of 2 Log CFU.mL-1 after treatment of 30 min with 500 μg / mL of sophorolipids in the water solution.