A scalable bioprocess for degradation of dairy proteins using immobilized cell-envelope proteinases

Proteolytic enzymes play an important role in research labs and industries ranging from food, pharmaceuticals and diagnostics to waste treatments and the textile industry. In the food industry, enzymatic hydrolysis of proteins is a mild process that can improve the physical, chemical, and organoleptic properties of the original food without compromising the nutritive value. In this work, a bioprocesses based on immobilized cell-envelope proteinases from Lactobacillus delbrueckii subsp. lactis 313 has been developed for degradation of dairy proteins. Polyester fabrics were packed in a column and enzymes were in situ immobilized onto polyester matrix via amine functionalization and glutaraldehyde cross-linking. The bioprocess using the fixed-bed enzyme reactor was evaluated for the degradation of casein protein and skimmed milk proteins (SMP). The degradation and subsequent peptide formation were monitored by measuring of the degree of hydrolysis (DH) for both proteins. RP-HPLC and SDS-PAGE profiles of hydrolysates showed peptide fragments having properties different from the parent proteins, demonstrating that this bioprocess is effective for degradation of dairy proteins. The bioprocess based on fixed-bed bioreactor is simple, cheap and scalable, making it industrially feasible for the production of peptides from milk proteins.