Production of a potentially probiotic culture of Lactobacillus casei subsp. casei CECT 4043 in whey

Batch and fed-batch fermentations for the production of a highly concentrated culture of Lactobacillus casei CECT 4043 were carried out in whey-based media. In batch fermentation, the maximum concentrations of biomass (0.33 g L−1) and antibacterial activity (3.42 AU mL−1) were obtained in diluted whey medium (2% w/v lactose, initial pH 7.0) after 12 h. Based on these results, biomass and antimicrobial metabolites production in two re-alkalized fed-batch fermentations were carried out in diluted whey medium. The first fed-batch culture was fed with concentrated whey (5% w/v lactose) and a 400 g L−1 concentrated lactose solution. The second culture, which was fed with a concentrated mussel processing waste (10% w/v glucose) and a 310 g L−1 concentrated glucose solution, provided the highest concentrations of biomass (1.7 g L−1), viable cells (∼1.7 × 1010 cfu mL−1), lactic acid (27.8 g L−1), acetic acid (3.9 g L−1) and antibacterial activity (74.2 AU mL−1).