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 (7 mg/ml),
extract of yeast (2.5 mg/ml), NaCl (3 mg/ml), NH4Cl (6 mg/ml), and of MgSO4 (0.3 mg/ml). In fermentor it
also proved that the maximum of xylanolytic activity (10.81 U/ml) was observed at the end of the growth
phase. Best enzyme activity was observed at the temperature of 50 ◦C and at pH 7.0. In the presence of
metal ions such asMn2+, the activity of the enzyme increased, the enzyme retained 50% of its activity after
7 h at 50 ◦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.