Abstract

SERNA-COCK, LILIANA; VALENCIA H, LEIDY JOHANA  and  RUALES S, ANGELA VIVIANA. EFFECT OF EXTRINSIC FACTORS ON THE ANTIMICROBIAL ACTIVITY OF W10B METABOLITE PRODUCED BY Weissella confusa. Rev.Bio.Agro [online]. 2014, vol.12, n.1, pp.71-78. ISSN 1692-3561.

Antimicrobial substances produced by lactic acid bacteria (LAB) may lose activity due to extrinsic factors. This study determined the effects of temperature, pH, and exposure to enzymes, on the activity of antimicrobial compounds (W10b) isolated from LAB Weissella confusa. W10b were active against Staphylococcus aureus and Streptococcus agalactiae. W. confusa was obtained by fermentation at 32°C for 4 h and W10b by centrifugation, microfiltration, and lyophilization from the resulting cell-free supernatant. W10b was exposed to acidic, neutral and basic pH, for two residence times (10 and 30 minutes) and four temperatures (27, 40, 60, and 100°C). The effect of the enzymes pepsin and amyloglucosidase on W10b was also determined. Significant differences (P<0,05) on the antimicrobial activity of W10b due to pH and temperature were found. The highest antimicrobial activity was obtained against S. aureus at basic pH and 27°C, and against S. agalactiae at neutral pH and 27°C. W10b presented sensitivity to the pepsin and amyloglucosidase enzymes, indicating the proteinaceous nature and chemical complexity of the compounds. Although further research is needed, antimicrobial compounds from W. confusa have a strong potential to be used in industrial setups.

Keywords : Bacteriocin; Lactic acid bacteria; Staphylococcus aureus; Streptococcus agalactiae.

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