Screening and Characterization of Marine <i>Bacillus atrophaeus</i> G4 Protease and Its Application in the Enzymatic Hydrolysis of Sheep (<i>Ovis aries</i>) Placenta for the Preparation of Antioxidant Peptides
Proteolytic enzymes, which play a crucial role in peptide bond cleavage, are widely applied in various industries. In this study, protease-producing bacteria were isolated and characterized from marine sediments collected from the Yellow Sea, China. Comprehensive screening and 16S rDNA sequencing id...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/10/2217 |
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| Summary: | Proteolytic enzymes, which play a crucial role in peptide bond cleavage, are widely applied in various industries. In this study, protease-producing bacteria were isolated and characterized from marine sediments collected from the Yellow Sea, China. Comprehensive screening and 16S rDNA sequencing identified a promising G4 strain as <i>Bacillus atrophaeus</i>. Following meticulous optimization of fermentation conditions and medium composition via response surface methodology, protease production using strain G4 was significantly enhanced by 64%, achieving a yield of 3258 U/mL. The G4 protease exhibited optimal activity at 50 °C and pH 7.5, demonstrating moderate thermal stability with 52% residual activity after 30-min incubation at 50 °C—characteristics typical of an alkaline protease. Notably, the enzyme retained over 79% activity across a broad pH range (6–11) and exhibited excellent salt tolerance, maintaining over 50% activity in a saturated NaCl solution. Inhibition by phenylmethylsulfonyl fluoride, a serine protease inhibitor, confirmed its classification as a serine protease. The enzyme’s potential in generating bioactive peptides was further demonstrated through hydrolysis of sheep (<i>Ovis aries</i>) placenta, resulting in a hydrolysate with notable antioxidant properties. The hydrolysate exhibited a 64% superoxide anion scavenging activity, surpassing that of reduced glutathione. These findings expand the current understanding of <i>Bacillus atrophaeus</i> G4 proteases and provide a foundation for innovative sheep placenta utilization with potential industrial applications. |
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| ISSN: | 1420-3049 |