The present disclosure concerns a co-culture of bacterial cells for making a fermented product from a biomass. The co-culture comprising a first recombinant lactic acid bacteria (LAB) cell expressing at least one bacteriocin and a second recombinant lactic acid bacteria (LAB) cell capable of converting, at least in part, the biomass into the fermented product. The second recombinant LAB cell is immune to the bacteriocin produced by the first recombinant LAB cell. The co-culture can be used, optionally in combination with a yeast host cell, to make a fermented product. The present disclosure also provides processes for making the fermented product by using the co-culture as wells kits and media comprising the co-culture.