NOVELTY - Biotechnological process for synthesis of a biomass involves a) culture propagation of Lactobacillus plantarum DSM 23213 and Lactobacillus sanfranciscensis DSM 23214 lactic acid bacteria; b) co-inoculation of a substrate selected from chemically defined medium (CDM), wheat flour hydrolyzate (WFH), grape must, milk serum or fruit and vegetable product extracts, with aqueous suspension of lactic acid bacteria in step (a); c) incubation; and optionally, d) centrifugation of the culture broth in order to remove the lactic acid bacteria cells.    USE - As a biotechnological process for synthesis of biomass comprising at least one plantaricin selected from plantaricins A, K and/or N and Lactobacillus plantarum DSM 23213 and Lactobacillus sanfranciscensis DSM 23214 lactic acid bacteria and for the preparation of plantaricins selected from plantaricins A, K and/or N used in preparation of medicament for increasing the barrier function of epidermis or intestinal wall, and for treating wound healing (claimed).    ADVANTAGE - The method prepares biomass comprising plantaricins in association with Lactobacillus plantarum DC400 (DSM 23213) and Lactobacillus sanfranciscensis DPPMA174 (DSM 23214) lactic acid bacteria exerts a higher effectiveness than plantaricin alone in enhancing the barrier function at level of epidermis or intestinal wall.    DETAILED DESCRIPTION - Biotechnological process for synthesis of a biomass comprising at least one plantaricin selected from plantaricins A, K and/or N and Lactobacillus plantarum DSM 23213 and Lactobacillus sanfranciscensis DSM 23214 lactic acid bacteria and for the preparation of plantaricins selected from plantaricins A, K and/or N involves a) culture propagation of Lactobacillus plantarum DSM 23213 and Lactobacillus sanfranciscensis DSM 23214 lactic acid bacteria; b) co-inoculation of a substrate selected from CDM, WFH, grape must, milk serum or fruit and vegetable product extracts, with aqueous suspension of lactic acid bacteria in step (a); c) incubation; and optionally, d) centrifugation of the culture broth in order to remove the lactic acid bacteria cells. An INDEPENDENT CLAIM is included for Lactobacillus plantarumDSM 23213 and/or Lactobacillus sanfranciscensis DSM 23214 lactic acid bacteria.