Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal by a Membrane Associated Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

Abstract

SummaryHypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the fi rst step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. Aft er enzymatic digestion, low-molecular-mass peptides were purifi ed with cross-fl ow fl at sheet membrane (pore size 100 μm) and then with tubular ceramic ultrafi ltration membrane (molecular mass cut-off 5 kDa). Eff ects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafi ltration membrane surface were examined and their positive eff ects were proven. For the fi ltration with ultrafi ltration membrane, transmembrane pressure of 3·10 5 Pa with 3-stage discontinuous diafi ltration was found optimal. The molecular mass distribution of purifi ed peptides using ultrafi ltration membrane was determined by a liquid chromatography-electrospray ionization quadrupole time-of-fl ight mass spectrometry setup. More than 96 % of the peptides (calculated as relative frequency) from the ultrafi ltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane fi ltration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9 %. It was also found that the peptides purifi ed in the ultrafi ltration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus.

Antioxidant and Antibacterial Peptides from Soybean Milk through Enzymatic- and Membrane-Based Technologies

“…Cumulative number of peptides, produced in batch-mode enzymatic hydrolysis reaction, offered a comparatively high zone of inhibition. In another investigation, we found that peptides with molecular weight lower than 5 kDa, produced by tryptic hydrolysis of defatted soybean meal protein, had antibacterial activity against Gram-positive B. cereus [8]. However, sources of peptides were different, i.e., soybean milk and defatted soybean meal, and they were prepared by enzymatic hydrolysis with papain and trypsin, respectively; their antimicrobial activity on test microorganism were similar.…”

“…After the experiment, ultrafiltration membrane was cleaned thoroughly with sequential way, as mentioned: (a) Cleaning with 10 g/L of ultrasil P3-11 for 30 min, (b) cleaning with deionized water for 30 min, (c) cleaning with 10 g/L of citric acid for 30 min, and (d) cleaning with deionized water for 1 h. Retentate flow rate of 200 L/h and trans-membrane pressure of 0.8 bar were used during the cleaning with ultrasil and citric acid, whereas trans-membrane pressure of 5 bar and retentate flow rate of 200 L/h were used during the cleaning with water [8]. Membrane hydraulic resistance (R m ) was estimated prior to the experiment, after the experiment, and membrane cleaning.…”

“…Antibacterial activity of native soybean milk, enzyme-hydrolyzed soybean milks, and permeate from membrane against Gram-positive Bacillus cereus was investigated with agar well method [8]. Microbial strain was collected from the Culture Collection of the Department of Microbiology and Biotechnology, Szent István University, Hungary.…”

“…At higher temperature, reversible reaction may reduce the activity of enzyme over time [55]. Other possible reasons of inactivation of an enzyme are compaction of the enzyme molecule, which may occurr by the generation of charged molecules around the enzyme and dissociation of enzyme structure at high temperatures [8,56].…”

Effect of Novel Engineered Aspergillus oryzae on Soybean Meal Fermentation and Optimization of Cultivation Conditions

“…As the byproduct of oil processing industry, soybean meal has high protein content and is an excellent raw protein material (Zheng et al, 2017;Rumsey et al, 1994;Mukherjee et al, 2016). However, soybean meal is currently mainly used as feed, with only a small part of it employed in fermentation and the majority of the protein material not being effectively utilized, resulting in wastage of resources (Lawrence et al, 2003;Ortega et al, 2016;Nath et al, 2017). Thus, the use of soybean meal as a raw material for further processing and comprehensive utilization has significant prospects (Wang et al, 2017;Liu et al, 2017;Yu et al, 2018).…”