ISOLATION, PARTIAL PURIFICATION AND CHARACTERIZATION OF 4 KDA BACTERIOCIN, PRODUCED BY Enterococcus faecalis AK71, WITH ACTIVITY AGAINST GRAM- POSITIVE AND GRAM-NEGATIVE BACTERIA

Metwally, M. M.; Abdel-Fattah, A. M.; Abdel-Ghany, S.; Geis, A.; Heller, K. J.; Okda, A. Y.

doi:10.21608/jfds.2008.125183

ISOLATION, PARTIAL PURIFICATION AND CHARACTERIZATION OF 4 KDA BACTERIOCIN, PRODUCED BY Enterococcus faecalis AK71, WITH ACTIVITY AGAINST GRAM- POSITIVE AND GRAM-NEGATIVE BACTERIA

Document Type : Original Article

Authors

¹ Dairy Science and Technology Dept,, Fac. Agric.,Cairo Univ., Cairo, Egypt.

² Dairy Microbiology Lab, Food Industries and Nutrition Division, NRC, Cairo, Egypt.

³ Federal Dairy Research Centre, Institute for Microbiology, Kiel, Germany.

10.21608/jfds.2008.125183

Abstract

Strain AK71, isolated from Egyptian fermented milk named Zabady, and identified as Enterococcus faecalis, produces a 4000 Da bacteriocin-like compound with inhibitory activity against Staphylococcus aureus 91161, Enterococcus faecalis 90519 and Serratia marcescens 98027. Bacteriocin AK71-like compound is inactivated by proteinase K but not when treated with catalase and trypsin. No change in activity was recorded after either 30 min or 2 h at pH values between 3.0 and 8.0, and after treatment at 100°C for 30 min. Activity was lost after treatment at 121°C for 20 min. The mode of action is bacteriostatic. The highest level of bacteriocin activity (51200 AU/ml) was recorded when cells were grown in MRS broth at 30°C for 12 h. Bacteriocin AK 71 shows activity towards Gram-negative bacteria making it different from most bacteriocins described for Enterococcus spp.

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