An extremely acidic extracellular chitinase produced by a Streptomyces sp. was purified 12.44-fold by
ammonium sulphate precipitation, ion-exchange chromatography and gel-permeation chromatography
and further characterised. The molecular mass of the enzyme was estimated to be about 40 kDa by
SDS–PAGE. The optimum pH and temperature of the purified enzyme were pH 2 and 6, and 50 C respectively.
The enzyme showed high stability in the acidic pH range of 2–6 and temperature stability of up to
50 C. Additionally, the effect of some cations and other chemical compounds on the chitinase activity
was studied. The activity of the enzyme was considerably retained under salinity conditions of up to
3%. The Km and Vmax values of the enzyme were determined to be 6.74 mg mL1 and 61.3 U mg1 respectively
using colloidal chitin. This enzyme exhibited antifungal activity against phytopathogens revealing
a potential biocontrol application in agriculture.