KERATIN DEGRADATION BY FERVIDOBACTERIUM PENNAVORANS, A NOVEL THERMOPHILIC ANAEROBIC SPECIES OF THE ORDER THERMOTOGALES

From a hot spring of the Azores islands a never thermophilic bacterium belonging to the Thermotogales order was isolated. This strain, which grows optimally at 70 degrees C and pH 6.5, is the first known extrem e thermophile that is able to degrade native feathers at high temperat ures. The enzyme system converts feather meal to amino acids and pepti des. On the basis of physiological, morphological, and 16S rDNA studie s the new isolate was found to be a member of the Thermotogales order and was identified as Fervidobacterium pennavorans, The strain was hig hly related to Fervidobacterium islandicum and Fervidobacterium pullul anolyticum. The cell-bound keratinolytic enzyme system was purified 32 -fold by detergent treatment with CHAPS lamidopropyl)dimethyl-ammonio] -1-propanesulfonate) and sodium dodecyl sulfate-polyacrylamide gel ele ctrophoresis. The enzyme was characterized as a serine protease with a molecular mass of 130 kDa and an isoelectric point of 3.8. Optimal ac tivity was measured at 80 degrees C and pH 10.0. Furthermore, 19 anaer obic thermophilic archaea and bacteria belonging to the orders Thermoc occales, Thermoproteales, Thermotogales, and Clostridiales (growth tem peratures between 60 and 105 degrees C) were tested for their abilitie s to grow on feathers and produce heat-stable keratinolytic enzymes, N one of the tested extremophilic microorganisms was able to attack the substrate in a native form.