title: Detergent-Stable Salt-Activated Proteinases from Virgibacillus halodenitrificans SK1-3-7 Isolated from Fish Sauce Fermentation.
abstract: The NaCl-activated and detergent-stable proteinases from Virgibacillus halodenitrificans SK1-3-7 isolated from fish sauce fermentation were purified and characterized. The enzymes with molecular masses of 20 and 36 kDa showed caseinolytic activity on a zymogram. Optimum azocaseinolytic activity was at 60 °C and pH 9. The proteolytic activity increased in the presence of 10 mM CaCl2 and 0.5 M NaCl and showed high stability at 0-2 M NaCl. The enzymes were stable at pH 4-10 and 10-50 °C. The enzymes preferably hydrolyzed Suc-Ala-Ala-Pro-Phe-pNA and were completely inhibited by phenylmethanesulfonyl fluoride (PMSF), showing subtilisin-like characteristics. Activity and stability remained high in the presence of H2O2 and various surfactants. The enzymes exhibited high stability (>95%) in various organic solvents (DMSO, butanol, ethanol, 2-propanol, and acetonitrile) at concentration of 50%. The V. halodenitrificans SK1-3-7 proteinases showed potential as a biocatalyst in aqueous-organic solvent systems and as an additive in laundry detergent.
authors.affiliation: School of Food Technology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
authors.forename: Aungkawipa
authors.initials: A
authors.lastname: Montriwong
authors.forename: Sureelak
authors.initials: S
authors.lastname: Rodtong
authors.forename: Jirawat
authors.initials: J
authors.lastname: Yongsawatdigul
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D003902:Detergents / Q000737:chemistry*; D004795:Enzyme Stability; D005396:Fish Products / Q000382:microbiology*; D006358:Hot Temperature; D010447:Peptide Hydrolases / Q000378:metabolism*; D012965:Sodium Chloride / Q000378:metabolism*; D058679:Virgibacillus / Q000254:growth & development*
chemical_list: D001426:Bacterial Proteins; D003902:Detergents; D012965:Sodium Chloride; D010447:Peptide Hydrolases