Dados do Trabalho

Título

ANTIFUNGAL AND PROTEOLYTIC ACTIVITY OF WEISSELLA CIBARIA/CONFUSA ISOLATED FROM CERRADO FRUIT BY-PRODUCTS

Introdução

Lactic acid bacteria (LAB) can be isolated from dairy products, vegetables and their technological characteristics have been studied in the area of biopreservation and optimization of the food fermentation process. The aim of this study was to investigate the antifungal and proteolytic activity of potentially probiotic strains of Weissella cibaria/confusa 11 and 12, isolated from pequi shell.

Material e Métodos

Man Rogosa and Sharpe agar plates (MRS) were used for growth of the sown LABs at three equidistant points and incubated anaerobically (37°C/24 h). 40 μL of the fungi Candida albicans ATCC 1023, Cryptococcus gattii WM178 and WM161, Penicillium sp. and Aspergillus fumigatus ATCC169, standardized with optical density of 1, were mixed with 0.7% dextrose potato agar (PDA) and overlaid onto MRS agar plates inoculated with BAL (28ºC/7 days). To evaluate proteolytic activity, 40 μL of each strain grown anaerobically in MRS broth was streaked on plate count agar with 10% (w/v) UHT skim milk and incubated anaerobically (30 °C/ 72 h). The plates were examined for the presence of clear inhibition zones around the areas colonized by the LAB.

Resultados e Discussão

W. cibaria/confusa 12 showed higher antifungal activity, forming larger halos against C. albicans ATCC 1023 (27.00 ± 2.65), Penicillium sp. (19.33 ± 4.04), C. gattii WM178 (8.33 ± 2.08) and C. gattii WM161 (2.66 ± 0.59). For the fungus A. fumigatus ATCC16913, W. cibaria/confusa 12 did not show antifungal activity. W. cibaria/confusa 11 showed smaller inhibition zones when compared to strain 12, but also but also formed wide halos against C. albicans ATCC 1023 (14.3 ± 1.53), followed by Penicillium sp. (12 ± 2.00) and C. gattii WM178 (10.53 ± 0.58). Strain 11 showed low activity against C. gattii WM161 (5.33 ± 0.58) and A. fumigatus (3.33 ± 2.08). Low proteolytic activity was found among the strains tested, which indicates low capacity to produce protease to reduce the allergenic potential of milk proteins.

Conclusão

The antifungal activity presented indicates future technological uses of LAB isolated from Cerrado fruits in the biocontrol of food products. Both tests performed are necessary for characterization of potentially probiotic bacteria.