Utilization of blood by-products: An in silico and experimental combined study for BSA usage

Abstract

In order to exploit industrial discards, protein enzymatic hydrolysis is a currently popular methodology for obtaining bioactive peptides. However, once released, most promising peptides have to be selected from the mixture. In this work, the suitability of pepsin (EC 3.4.23.1) to hydrolyse serum albumin in order to obtain bioactive peptides was assessed. Then, a suitable process to obtain best separation of bioactive peptides was evaluated, using polyethersulfone membranes at different pH values. Serum albumin was easily hydrolysed by pepsin, reaching a DH value of the 65.64 ± 1.57% of the maximum possible. A 23.25% of the identified peptides possessed high bioactivity scores (greater than 0.5), and one of them had reported bioactivity (LLL). Charge mechanisms always predominated over the sieve effect, and best transmission was accomplished at pH values close to the peptides isoelectric points. Basic and neutral peptides with the highest scores were always the most transmitted. Membrane material had greater influence than NMWCO in determining peptide transmission. In order to obtain purified fractions rich in peptides with high bioactivity scores from serum albumin, polyethersulfone membranes (applicable to industrial scale) of 5 kDa MWCO should be used at basic pH values after pepsin digestion.

Figure 1

Hydrolysis curve for BSA (3 g/L) digestion with pepsin (4% E:S ratio) at 37 °C and pH 2. Data are presented as mean ± error.

Figure 2

Observed and theoretical transmission values across PES1 membrane for BSA peptic hydrolysate identified peptides. Data are presented as mean ± error.

Figure 3

Observed and theoretical transmission values across PES5 membrane for BSA peptic hydrolysate identified peptides. Data are presented as mean ± error.