RESUMO
The progress in genetic engineering allows to employ still growing number of bacterial strains for recombinant gene expression. Among them are many lactic acid bacteria including Lactococcus lactis which belongs to the most developed ones. Those microorganisms are ideal for heterologous protein expression because they can synthesize nisin which is a bacteriocin that can be used as an inductor factor. The recently developed NICE system is molecular tool that allows to produce heterolguos proteins in Lactococcus lactis. The NICE system needs three components for correct operation: host strain, plasmid and inductor factor - nisin. The NICE system proved to be valuable tool for recombinant protein expression including synthesis of heterologous antimicrobial peptides, membrane proteins, and vaccines development.