CHARACTERIZATION OF AMYLOLYTIC AND PULLULYTIC ENZYMES FROM THERMOPHILIC ARCHAEA AND FROM A NEW FERVIDOBACTERIUM SPECIES

Nine extremely thermophilic archaea and Introduction one novel thermop hilic bacterium were screened for their ability to produce amylolytic and pullulytic enzymes. Cultivation of these micro-organisms was perfo rmed in the absence of elemental sulphur with starch as the major carb on source. Enzymatic activity was mainly detected in two archaea belon ging to the order Thermoproteales, Desulfurococcus mucosus and Staphyl othermus marinus, in two archaea belonging to the order Thermococcales , Thermococcus celer and T. litoralis and in two novel archaeal strain s, TYS and TY previously isolated from the Guaymas Basin in the Gulf o f California. Both amylolytic and pullulytic activities were also dete cted in a newly isolated thermophilic bacterium belonging to the order Thermotogales and previously described as Fervidobacterium pennavoran s. Best yields for enzyme production were obtained in 1-1 batch cultur es with the strains TYS (13 units U/1 of amylase, 6 U/1 of pullulanase ), F. pennavorans (2.5 U/1 of amylase, 4.5U/1 of pullulanase) and T. l itoralis (3.0 U/1 of amylase). Enzymes were in general characterized b y temperature optima around 90-100 degrees C, pH optima around 5.5-6.5 and a high degree of thermostability. Due to the remarkable propertie s of these enzymes, they are of interest for biotechnological applicat ions.