Fed-batch pediocin production on whey using different feeding media

Pediocin production by Pediococcus acidilactici NRRL B-5627 was followed in both batch and re-alkalized fed-batch fermentations on diluted whey (DW) supplemented with 2% (w/v) yeast extract (DWYE2 medium). In the first fed-batch culture, the fermentor was fed with a mixture of a 400 g/L concentrated lactose and concentrated whey (CW) supplemented with 2% (w/v) yeast extract. The maximum pediocin concentration obtained was only 1.2-fold higher than in batch fermentation. Since supplementing the DW with increasing amounts of glucose inhibited pediocin production, a second re-alkalized fed-batch culture was carried by using a 400 g/L concentrated glucose as feeding substrate. The pediocin concentration obtained was 2.2-fold higher than that in the first fed-batch culture. The third fed-batch fermentation was carried out by feeding the growing culture with a mixture of a 400 g/L concentrated glucose and CW medium supplemented with 4% (w/v) yeast extract. The concentration of biomass and the volumetric pediocin productivity obtained in this last culture were higher than those obtained in both the batch and the two fed-batch cultures (P < 0.05). Therefore, the use of feeding substrates containing glucose instead of lactose could be an appropriate alternative for increasing fed-batch production of pediocin in DWYE2 medium.