Isolation, identification and characterization of a novel elastase from Chryseobacterium indologenes

Elastase is a type of protease that specifically degrades elastin. It has broad application prospects in medicine, food industry, and daily-use chemical industry. In this study, we isolated a bacterial strain WZE87 with high elastin-hydrolysis activity, which was identified as Chryseobacterium indologenes based on morphology, physiological and biochemical characteristics, and 16S rDNA sequence analysis. The elastase produced by this strain was purified by three steps: ammonium sulfate precipitation, Q-Sepharose fast-flow anion-exchange chromatography, and Sephadex G-75 gel-filtration chromatography. The purified elastase was 2376.5 U/mg in activity (a 8.3-fold increase in specific activity), and the recovery was 5.8%. Its molecular mass was estimated to be 26 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This enzyme was stable in the pH range of 5.0-10.5 at 37 degrees C. The optimal temperature and pH were 37 degrees C and 7.5, respectively. The activity of this elastase was found to decrease when the temperature was higher than 50 degrees C. The activity was also inhibited by Zn2+, Fe2+, Fe3+, and Mn2+ ions. The specific hydrolytic ability of this enzyme was similar to that of papain on substrates like gelatin, casein, soybean-isolated protein and bovine hemoglobin. However, this elastase preferentially hydrolyzed elastin in a protein mixture because of its specific adsorption. Considering its promising properties, this protease may be considered a potential candidate for applications in related industries.