Bioprospection of proteases from Halobacillus andaensis for bioactive peptide production from fish muscle protein

BACKGROUND: Biologically active peptides produced from fish wastes are gaining attention because their health benefits. Proteases produced by halophilic microorganisms are considered as a source of active enzymes in high salt systems like fish residues. Hence, the aim of this study was the bioprospection of halophilic microorganisms for the production of proteases to prove their application for peptide production. RESULTS: Halophilic microorganisms were isolated from saline soils of Mexico and Bolivia. An enzymatic screening was carried out for the detection of lipases, esterases, pHB depolymerases, chitinases, and proteases. Most of the strains were able to produce lipases, esterases, and proteases, and larger hydrolysis halos were detected for protease activity. Halobacillus andaensis was selected to be studied for proteolytic activity production; the microorganism was able to grow on gelatin, yeast extract, skim milk, casein, peptone, fish muscle (Cyprinus carpio), and soy flour as protein sources, and among these sources, fish muscle protein was the best inducer of proteolytic activity, achieving a protease production of 571 U/mL. The extracellular protease was active at 50°C, pH 8, and 1.4 M NaCl and was inhibited by phenylmethylsulfonyl fluoride. The proteolytic activity of H. andaensis was used to hydrolyze fish muscle protein for peptide production. The peptides obtained showed a MW of 5.3 kDa and a radical scavenging ability of 10 to 30% on 2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and a ferric reducing ability of plasma. Conclusion: The use of noncommercial extracellular protease produced by H. andaensis for biologically active peptide production using fish muscle as the protein source presents a great opportunity for high-value peptide production.

Short-Term Intake of Fish Protein Contained in Fish Sausage Improved Lipid Profiles in Hypercholesterolemia Patients: Baseline and Post-Intervention Effects / 日本補完代替医療学会誌

Fish sausage is a common food in Japan. It is mainly made from <i>surimi</i>, which contains a high amount of fish protein. Although it has been reported that the administration of fish protein reduces blood total cholesterol, LDL-cholesterol, and triglycerides in experimental animals, it has not been studied whether the intake of fish protein improves blood cholesterol profiles in humans. In the present study, male subjects (n = 20) with fasting blood LDL-cholesterol (140–179 mg/dL) were enrolled. Subjects consumed a total of 225 g of fish sausage daily for 8 weeks, and the total ingestion dose of fish protein was 13.5 g/day. Blood total cholesterol, LDL-cholesterol, and atherogenic index were significantly reduced (<i>p</i> < 0.01, <i>p</i> < 0.05, and <i>p</i> < 0.01, respectively), and HDL-cholesterol was significantly increased (<i>p</i> < 0.01) by fish sausage intake after 4 and/or 8 weeks of intervention without side effects. These results imply that the short-term intake of fish protein achieved by the eating of fish sausage improves cholesterol profiles in hypercholesterolemia subjects.<br>