BETA-AMYLASE FROM CLOSTRIDIUM-THERMOCELLUM SS8 - A THERMOPHILIC, ANAEROBIC, CELLULOLYTIC BACTERIUM

The extracellular amylase produced by Clostridium thermocellum strain SS8 on starch was characterized as a beta-amylase based on blue value reduction test and the production of maltose from starch. The enzyme h ad a temperature and pH optima of 60-degrees-C and 6.0, respectively. Of the metal ions tested, Ca2+ and Mg2+ had little effect on enzyme ac tivity, but their presence increased its thermal stability. Ca2+ displ ayed a higher stabilizing effect and at 10 mmol l-1 Ca2+, the enzyme r etained 86% activity even after exposure at 70-degrees-C for 30 min. T he amylase was induced on starch or maltose but was repressed strongly by glucose.