title: Purification and characterization of a new neutral metalloprotease from marine Exiguobacterium sp. SWJS2.
abstract: Among the protease-producing bacterial strains isolated from deep-sea sediments, SWJS2 was finally selected and identified as genus Exiguobacterium. Plackett-Burman and orthogonal array designs were applied to optimize the fermentation conditions, and the results are as follows: Glucose 5g, yeast extract 15g, glycerin 2g and CaCl2 ⋅2H2 O 0.5 g dissolved in 1 L artificial seawater; temperature 25 °C, original pH 7, inoculum rate 2%, seed age 12 H, loading volume 25 mL (250-mL Erlenmeyer flask), shaking speed 150 rpm, and fermentation time 44 H. The protease activity production was improved from about 80 to 660 U/mL under the optimized parameters. The protease was purified fourfold with specificity activity of 30,654.1 U/mg protein and a total yield of 16.2%. The protease exhibited the maximum activity at 40-45 °C and pH 7. Moreover, the enzyme activity was found to be inhibited by Cu(2+) , Ba(2+) , Cd(2+) , Hg(2+) , and Al(3+) at 5 mM, whereas it can be increased by Mg(2+) , Mn(2+) , and Ca(2+) at 0.5-5 mM. The enzyme was totally inactivated by 1 or 5 mM ethylenediaminetetraacetic acid but not by phenylmethanesulfonyl fluoride, tyrpsin inhibitor from Glycine max (STI), benzamidine, 5,5'-dithio-bis-(2-nitro benzoic acid), or pepstatin A, suggesting that it belonged to metalloprotease.
authors: College of Light Industry and Food Science, South China University of Technology, Guangzhou, People's Republic of China.|Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, People's Republic of China.
authors: Fenfen
authors: F
authors: Lei
authors: College of Light Industry and Food Science, South China University of Technology, Guangzhou, People's Republic of China.|Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, People's Republic of China.
authors: Chun
authors: C
authors: Cui
authors: College of Light Industry and Food Science, South China University of Technology, Guangzhou, People's Republic of China.|Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, People's Republic of China.
authors: Haifeng
authors: H
authors: Zhao
authors: College of Light Industry and Food Science, South China University of Technology, Guangzhou, People's Republic of China.|Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, People's Republic of China.
authors: Xuelu
authors: X
authors: Tang
authors: College of Light Industry and Food Science, South China University of Technology, Guangzhou, People's Republic of China.|Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou, People's Republic of China.|State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, People's Republic of China.
authors: Mouming
authors: M
authors: Zhao
mesh_terms: D056449:Bacillales / Q000201:enzymology*; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D045726:Metalloproteases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D012965:Sodium Chloride / Q000737:chemistry
chemical_list: D012965:Sodium Chloride; D045726:Metalloproteases
keywords: Exiguobacterium sp; enzyme characteristics; marine bacteria; protease; purification