The role and significance of natural plasmids existing in lactic acid bacteria (LAB) from genus Lactococcus, Lactobacillus and Leuconostoc in their metabolic diversity and industrially important properties have been described. Molecular organization of plasmids, their mechanisms of replication and metabolic activity were discussed in detail with particular stress put on their common features such as structure similarity, segregational and structural stability, biochemical traits and the presence of insertion sequences. The role of plasmid borne IS elements on plasmid stability and adaptative properties of LAB were also discussed.
Piotr Walczak, Wydzial Biotechnologii i Nauk o Zywnosci, Instytut Technologii Fermentacji i Mikrobiologii, Politechnika Lodzka, ul Wolczanska 171/173, 90-530 Lodz, Poland