Production and Characterization of Fibrinolytic Enzyme from Bacillus amyloliquefaciens in 19 L Fermenter and Investigation of Its Properties
As an extension of our previous fermentation experiments in shake flasks,the objective of this study was to optimize the fermentation conditions for the production of fibrinolytic enzyme by Bacillus amyloliquefaciens GZJSI-12-7 in a 19 L fermenter.The results showed that plasmin activity began to appear after incubation for 6 h and remained constant after 78 h at a level of 4 178.39 IU/mL.The peak of enzyme production occurred about 12 h earlier than in shake flasks.Fibrinolytic enzyme was purified from the fermented liquid medium by bactofugation,ammonium sulfate precipitation,dialysis and Sephadex G-75 gel filtration,with a purification fold of 9.84 and an activity recovery of 42.52％.The specific activity of the purified fibrinolytic enzyme was 48 073.193 IU/mg.Enzymatic characterization showed that the molecular weight of the fibrinolytic enzyme was about 30.2 kD,and its optimum temperature and pH were 40 ℃ and 7.5,respectively.The purified fibrinolytic enzyme was stable blow 40 ℃ but sharply decreased above 50 ℃.The enzymatic activity was markedly catalyzed by Mg2+,Ca2+ and Mn2+,but strongly inhibited by Cu2+ and Fe3+.
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