Characterization of an antibiotic produced by Alteromonas luteoviolacea Gauthier 1982,85 isolated from Kinko Bay, Japan

An antibiotic produced by Alteromonas luteoviolacea strain 9K-V10 was recovered after cold acetone precipitation of culture supernatant fluids or lysates that had been frozen and thawed. The precipitate obtained from cell-free lysates was fractioned by DEAE ion-exchange chromatography. Further purification by gel-filtration chromatography yielded a single peak of antibiotic activity that corresponded to a protein peak with a molecular mass of approximately 100 kDa. After non-denaturing polyacrylamide gel electrophoresis, antibiotic activity co-migrated with a protein band. The isoelectric point of the antibiotic was estimated to be 7.7. Treatment of the concentrated active fraction with proteinase K or heating at 70 degrees C for 10 min resulted in total loss of antibiotic activity. These results show that the antibiotic produced by Alt. luteoviolacea 9K-V10 is of a proteinaceous nature.