초록
Jonesia denitrificans BN-13 was isolated from a sample collected from Algerian soil. This strain produced extracellular xylanases, the best xylanolytic activity is obtained in a medium made up of xylan (7mg/ml), extract of yeast (2.5mg/ml), NaCl (3mg/ml), NH<SUB>4</SUB>Cl (6mg/ml), and of MgSO<SUB>4</SUB> (0.3mg/ml). In fermentor it also proved that the maximum of xylanolytic activity (10.81U/ml) was observed at the end of the growth phase. Best enzyme activity was observed at the temperature of 50<SUP>o</SUP>C and at pH 7.0. In the presence of metal ions such as Mn<SUP>2+</SUP>, the activity of the enzyme increased, the enzyme retained 50% of its activity after 7h at 50<SUP>o</SUP>C. As such, this enzyme could be considered as a thermotolerant biocatalyst being interesting for biotechnological applications. At the best of our knowledge, this is the first report on the production of xylanase by this bacterium and especially the genus Jonesia.