GOS from Porungo Cheese Whey: Batch, Repeated Batch, and Continuous Bioreactors

This study aimed at producing galactooligosaccharides (GOS) from Porungo cheese whey in immobi-lized enzyme bioreactors. The β-galactosidase was produced, concentrated, and immobilized on chi-tosan-genipin supports. Initially, GOS production was conducted in conical flasks, investigating three different variables: enzyme concentration (50 U/mL - 150 U/mL), Porungo cheese whey concentration (200 g/L - 400 g/L), and temperature (37 – 43 ºC). The highest GOS yields (15.24 %) occurred under intermediate process conditions (100 U/mL, 300 g/L, 40 ºC), reaching a GOS concentration of 27.04 g/L. These conditions were then used in a packed-bed column bioreactor operated in batch mode, achieving yields of 19.72 %. Repeated batches were carried out, and the system was stable until the fifth cycle, with enzyme activity remaining at 83.56 % of the initial level. Continuous bioreactors were conducted, varying feed flow rates (1 mL/h - 3 mL/h), with the highest yields and lactose conversion occurred for the longest residence time (24.63 % and 68.38 %), respectively, with high GOS concentra-tion (44.14 g/L). Microorganisms isolated from Porungo cheese showed the ability to metabolize the GOS produced, demonstrating its prebiotic potential. This work can contribute to optimizing the production of GOS, an important product for pharmaceuticals and food industries.