Full Length Research Paper

Statistical optimization of activity and stability of β-xylanase produced by newly isolated Thermomyces lanuginosus THKU-49 using central composite design

Khwanchai Khucharoenphaisan¹, Shinji Tokuyama² and Vichien Kitpreechavanich¹*

¹Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.

²Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529 Japan.

*Corresponding author. E-mail: fsciwck@ku.ac.th. Tel: +81-2-5792351. Fax: +81-2-5792081.

Accepted 16 September, 2008

A factorial design was performed to find the best conditions of pH and temperature for β-xylanase activity and to maintain its activity for prolonged periods of time of pure xylanase produced by newly isolated Thermomyces lanuginosus THKU-49. The central composite design (CCD) used for the analysis of treatment combinations showed that a regression models of optimization of xylanase activity and xylanase stability were good agreement to experimental results with R² = 0.98 and 0.99, respectively. The maximum activity of xylanase was obtained at 66^oC and pH 6.3.  The temperature and pH for maximum enzyme stability was 70^oC and pH 7.3, respectively. Under this condition xylanase having half-life of 825 min indicated the highest thermostable xylanase.

Key words: β-xylanase, optimization, central composite design.