Screening of a Novel Fibrinolytic Enzyme-Producing Streptomyces from a Hyper-Arid Area and Optimization of Its Fibrinolytic Enzyme Production

Fibrinolytic enzymes are a kind of proteolytic enzymes that can hydrolyze fibrin and dissolve blood clots. They could be used as a therapeutic agent for treating thrombosis. It is important for the treatment of cardiovascular disease to find and develop new thrombolytic drugs. In order to explore new fibrinolytic enzymes, a strain named 214L-11 with protease and fibrinolytic enzyme activity, which was isolated from the Flaming Mountain of Xinjiang Province, was screened using the skimmed milk plate, the blood powder agarose plate and the fibrin plate methods. Phylogenetic analyses showed that strain 214L-11 shared the highest similarity with Streptomyces fumanus NBRC 13042T (98.88%), which indicated that it represented a potential novel species in the Streptomyces genus. The fibrinolytic enzyme produced by 214L-11 displayed thrombolytic and anticoagulant activities, and it could degrade a single specific protein in the thrombus, thereby destroying the thrombus structure. The fermentation medium optimized through response surface methodology was 15 g/L soluble starch, g/L KNO₃ 0.58, 0.43 g/L peptone, 0.01 g/L FeSO₄·7H₂O, 0.5 g/L MgSO₄·7H₂O, 0.2 g/L Mn²⁺, 0.5 g/L NaCl and 1 L distilled water, pH 8, and the maximum amount of fibrinolytic enzyme produced by strain 214L-11 in the optimal fermentation medium was 1255.3 FU/mL. Overall, the fibrinolytic enzyme-producing strain was screened from the Flaming Mountain of Xinjiang for the first time, which provided a basis for further research and the development of new efficient and safe hemolytic drugs.