(EN) The invention describes the use of a method for expressing proteins in bacteria, which is based on the inducing effect, for instance, of a carbohydrate upon the antiterminator activity of a protein of the family of antiterminators BlgG/SacY. The method has been tested with the system derived from operon lacTEGF inducible by lactose in Lactobacillus casei for expressing various types of proteins. The invention includes expression examples of multicopy or integration plasmids in chromosome operon lacTEGF thereby obtaining coordinated expression of the desired genes together with the genes coding for the enzymes of lactose metabolism.