CHAPTER 7 - Molecular Biology of Bacteriocins Produced by Lactobacillus

Abstract

This chapter discusses the molecular biology of bacteriocins produced by Lactobacillus. Antimicrobial proteins and peptides produced by a variety of Lactobacillus strains are antagonistic toward other competitive microorganisms. Such natural inhibitors can also contribute to the margin of safety in processed foods where the bacteriocins are effective against targeted foodborne pathogens. The targets of genetic and protein engineering of Lactobacillus bacteriocins lie in: (1) the operon promoter region, (2) the structural gene, (3) the bacteriocin leader sequence, (4) the immunity gene, and (5) the effects of any genetic changes on the accompanying export and processing mechanisms. Understanding pre/pro protein structures and posttranslational processing enzymes produced from these operons elucidates important structure—function relationships of these bacteriocins. Information about bacteriocin resistance mechanisms and their development within sensitive populations will be critical in order to optimize the effectiveness and longevity of food preservation and fermentation systems. Leader peptide sequences can be used to direct the processing or export of heterologous bacteriocins or proteins cloned in Lactobacillus.