ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Food Microbiology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1595109
A Halophilic Metalloprotease from Salinivibrio sp. YH4 and Its Application in Antioxidant Peptide Production
Provisionally accepted
- 1Guangxi Medical University, Nanning, Guangxi Zhuang Region, China
- 2Central South University, Changsha, China
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The sustainable utilization of protein-rich industrial by-products has long presented a critical challenge in biotechnology. In this study, a moderately halophilic bacterium, Salinivibrio sp. YH4, was isolated from the hypersaline sediments of Yuncheng Salt Lake, China. This bacterium secreted a novel metalloprotease (EYHⅢ) capable of transforming collagen waste into bioactive peptides. Phylogenetic analysis revealed 99% 16S rRNA homology with Salinivibrio costicola. Biochemical characterization identified EYHⅢ as a thermostable (50-60°C) and alkaliphilic (pH 7.5-9.5) M4-family metalloprotease. The enzyme retained >80% activity under high salinity conditions (1 M NaCl) and exhibited strict substrate specificity for hydrophobic residues (Phe/Leu) at the P1' position. It efficiently hydrolyzed both soluble and insoluble collagens. Fish collagen hydrolysates generated by EYHⅢ demonstrated potent antioxidant activity, scavenging 33.53 ± 3.30% of DPPH radicals and 45.55 ± 3.00% of hydroxyl radicals at 3 mg/mL, with a peroxyl radical absorbance capacity of 1.69 ± 0.07 mmol TE/g. In human umbilical vein endothelial cells (HUVECs), the hydrolysate reduced high glucoseinduced reactive oxygen species (ROS) to baseline levels at 200 μg/mL. It also significantly upregulated antioxidant enzymes compared to damaged controls: superoxide dismutase (SOD, 103.55%), catalase (CAT, 110.96%), and glutathione peroxidase (GSH-Px, 135.79%) (all P < 0.05). This study highlighted Salinivibrio sp. YH4 and its protease EYHⅢ as a sustainable platform for converting collagen waste into high-value antioxidants. These findings addressed both environmental pollution and the growing demand for functional bioactive compounds. The results underscored the potential of halophilic biocatalysts in advancing circular economy strategies for protein resource utilization.
Keywords: Salinivibrio, Metalloprotease, Collagen hydrolysis, antioxidant, Oxidative Stress
Received: 17 Mar 2025; Accepted: 21 Apr 2025.
Copyright: © 2025 Liu, Xiao, Wei, Xie, Huang, Gan and He. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Dan Liu, Guangxi Medical University, Nanning, 530021, Guangxi Zhuang Region, China
Hailun He, Central South University, Changsha, China
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