Generation of antioxidant peptides from soy protein isolate through psychrotrophic Chryseobacterium sp. derived alkaline broad temperature active protease

Abstract

Antioxidant peptides confer numerous health benefits. Unexplored niches provide bioprospection opportunities for potential protease producing microorganisms that are useful in releasing antioxidant peptides from protein sources impacting human health. A cold-adapted bacterium Chryseobacterium polytrichastri ERMR1:04 produced an extracellular protease enzyme optimally at 20 °C, pH 8 with 1.25 g/100 mL skim milk inducer. The purified 22.24 kDa protease was active over a broad temperature 5–65 °C (optimum at 37 °C) and pH 6–10 (optimum at pH 8) range, inhibited by EDTA and 1, 10-phenanthroline, enhanced by Ca2+, Mn2+ and hexane, and retained its activity with surfactants and detergents. ERMR1:04 protease-mediated hydrolysis of soy protein generated antioxidant peptides of <6 kDa, with successful identification, showing radical scavenging activities of 77% DPPH, 96% ABTS, 93% ferrous ion chelation, and Abs700 0.159 for reducing power assay. Such promising properties qualify the ERMR1:04 protease as a potent catalyst for high-value functional food production.