[Studies on elastase from Flavobacterium. I. Strain screening and enzyme purification].

132 strains bacteria secreting extracellular elastase were isolated from soil samples, 5 of them possessed considerably high elastiolytic activity of more than 100 u/ml. The highest-yield strain No. 17-87 was characterized as Flavobacterium odoratum, studies on the condition of elastase production revealed that its optimum carbohydrate and nitrogen source were glucose and casein respectively, and that it could utilize fowl ferther meal and wheat bran to give 80% relative yield. The culture exhibited maximum elastase activity at 26 degrees C for 21 hours, the productivity could be increased when the aeration was improved. The PAGE-homogenous elastase preparation was obtained from the culture broth by (NH4)2SO4 fractionation, DEAE-cellulose column chromatography and gel filtration on Sephadex G-75. The molecular weight was determined to be 21380 by SDS-PAGE, the elastiolytic activity was optimal at pH7.4 and 50 degrees C. The enzyme was stable over the range of pH4.5-9.5 and below 40 degrees C, but the activity was inhibited completely by Fe3+, Zn2+, Cu2+, Cr3+, Co2+, Ni2+, Hg2+, Ag+.