Protein enzymatic hydrolysis integrated with ultrafiltration: Thermolysin application in obtaining peptides

In this manuscript, enzymatic proteolysis in order to obtain short peptides was discussed. To hydrolyse serum bovine albumin (BSA) thermolysin (TLN) was used and the molecular mass and concentration of hydrolysates utilising SE-HPLC were identified. It was found that the substrate pre-incubation at high temperatures (>46 degrees C) contributed to the increase of hydrolysis rate and final efficiency. At a temperature of 70 degrees C there is a negative effect, resulting from the aggregation of albumin molecules. It is worthy of notice that the pre-incubation time is significant, up to half an hour. A strong product inhibition was observed. It resulted in the low values of hydrolysis degree (DH) obtained in classical reactors. Various reaction mechanisms have been tested to elucidate the best kinetic model. The kinetic equation was adopted and its constant values were estimated. A qualitative and quantitative description of the proteolysis products was performed. An ultrafiltration membrane with small pore-size, in order to remove peptides, the enzyme inhibitors, was selected. Obtained results indicate that the enzymatic process can be significantly intensified in an integrated bioreactor-ultrafiltration environment. In addition, it is clear that process efficiency and permeate composition depend on the proper selection of the dilution rate and the separation properties of the membrane. (C) 2016 Elsevier B.V. All rights reserved.