Keratin degradation by feividobacterium pennavomns, a novel thermophilic anaerobic species of the order thermotogales

Abstract

From a hot spring of the Azores islands a novel thermophilic bacterium belonging to the Thermotogales order was isolated. This strain, which grows optimally at 70°C and pH 6.5, is the first known extreme thermophile that is able to degrade native feathers at high temperatures. The enzyme system converts feather meal to amino acids and peptides. On the basis of physiological, morphological, and 16S rDNA studies the new isolate was found to be a member of the Thermotogales order and was identified as Fervidobacterium pennavorans. The strain was highly related to Fervidobacterium islandicum and Fervidobacterium pullulanolyticum. The cell-bound keratinolytic enzyme system was purified 32-fold by detergent treatment with CHAPS (3-[(3-cholamidopropyl)dimethyl-ammonio]-1-propanesulfonate) and sodium dodecyl sulfate-polyacrylamide gel clcctrophoresis. The enzyme was characterized as a serine protease with a molecular mass of 130 küa and an isoelcctric point of 3.8. Optimal activity was measured at 80°C and pH 10.0. Furthermore, 19 anaerobic thermophilic archaea and bacteria belonging to the orders Thermococcales, Thermoproteales, Thermotogales, and Clostridiales (growlh temperatures between 60 and 105C) were tested for their abilities to grow on feathers and produce heat-stable keratinolytic enzymes. None of the tested extremophilic microorganisms was able to attack the substrate in a native form. Copyright © 1996, American Society for Microbiology.