Screening of strains identified as extremely thermophilic bacilli for extracellular proteolytic activity and general properties of the proteinases from two of the strains

摘要: T. COOLBEAR, C.W. EAMES, Y. CASEY, R.M. DANIEL AND H.W. MORGAN. 1991. Forty-one strains isolated from thermal areas in New Zealand, Fiji and Antarctica were shown to be extremely thermophilic Bacillus spp. (growth optima > 65.C) by comparison with reference a series of standard tests. Some morphological physiological variation between was noted. Various assay procedures employed assess the for their ability produce extracellular proteolytic activity. The strain EA. 1 gave highest yield activity under conditions imposed. A second strain, OK3A.1, also high yields but differed EA.1 that it more tolerant both pH EDTA. proteinases these two purified characterized. Maximum given proteinase over narrow range an optimum at 6.7 50% limits 5.6 7.5. OK3A.1 had similar active broader 5.2 8.5. Both enzymes endo-acting proteinases; neither showed against small synthetic peptides. By SDS-polyacrylamide gel electrophoresis molecular masses 42 000 Da 32 respectively. resistant 10 mmol/1 phenylmethylsulphonylfluoride iodoacetic acid, deactivated Whereas inhibited o-phenanthroline activated zinc ions, unaffected either agent although some dependence on divalent metal ions apparent. stabilized calcium exhibiting half-life 2 h 85.C whilst less stable 40 min this temperature.