Characterization of a thermostable and acidic-tolerable beta-glucanase from aerobic fungi Trichoderma koningii ZJU-T.

An extreme thermostable and acidic tolerable beta-glucanase was isolated and characterized from aerobic fungi Trichoderma koningii ZJU-T. The optimal reaction temperature and pH for the beta-glucanase were 100 degrees C and pH 2.0, respectively. The beta-glucanase showed increased stability at higher temperatures and lower pH values when compared to other beta-glucanases. The optimum conditions for the beta-glucanase stability were found to be pH 4.0 and 80 degrees C. Even subjected to 100 degrees C for 3 h, beta-glucanase activity did not show significant reduction. Moreover, K(+) significantly enhanced beta-glucanase activity at the concentration of 1 mM, while EDTA and other metal ions such as Mg(2+), Mn(2+), Zn(2+), Ca(2+), Fe(2+), Pb(2+), and Fe(3+) inhibited beta-glucanase activity. Denaturants, including sodium dodecyl sulfate (SDS) and mercaptoethanol, also inhibited beta-glucanase activity at a concentration of 5%. However, in the presence of 7 M urea, residual activity of the beta-glucanase still remained 14.5%.