Different strategies for purification of antimicrobial peptides from Lactic Acid Bacteria (LAB)

Bacteriocins are natural peptides secreted by several bacteria that exert bactericidal activity against other bacterial species. Research in this topic is promoted not only by the need to develop alternatives to antibiotics and drugs that have shown non-desirable effects, but also to the capacity of some bacteriocin to inhibit saprophytic and food-borne pathogens in food stuffs. Many LAB are bacteriogenics, and the purification of the bacteriocins produced is helpful for the knowledge of the mechanism of action, structure, and other characteristics, which helps to isolate the bacteriocin biosynthetic genes. In this chapter, different techniques applied to purify some bacteriocins from LAB are described. The most frequently applied techniques involve salt precipitation followed by various combinations of ion-exchange (IEC) and reverse phase C18 solid phase extraction, absorption-desorption (AD), reverse-phase highperformance liquid chromatography (RP-HPLC) and Sodium Dodecyl Sulphate Polyacrilamide Gel Electrophoresis (SDS PAGE). The results obtained through the purification of different LAB bacteriocins (enterocin and salivaricin) carried out in our laboratory are included to discuss the different purification strategies applied.