High-yield Production And Characterization Of Xylanase From Thermomyces Lanuginosus DSM 10635

This thesis describes the high level production and properties of xylanase from Thermomyces lanuginosus DSM 10635.The production of xylanase correlates with substrates, culture temperatures, substrate particle size, moisture content investigated. And the highest total xylanase production by T. lanuginosus DSM 10635 was achieved 12525.80IU/g under the optimal solid-state cultivation. Among the substrate tested such as corncob, corn husk, corn stalk, pine powder, birch powder and wheat bran, it was shown that corncob is the best substrate for xylanase production. And the corncob particle diameter around 1mm is the most suitable for xylanase production. Furthermore, the xylanase was preferentially produced at 50-55℃while moisture content with dry corncob/water ratio as 1/2.8 was more favorable. The partial characterizaions of xylanase from T. lanuginosus DSM 10635 were also studied.In 10 min, the optimal pH and temperature for the xylanase activity were at 6.5 and 70°C, respectively. The xylanase was stable in a wide range of pH 5.5–9 in a 30 min incubation at 65℃, with an optimum stability at pH 6.5. In addition, after incubation for 30 min at 70℃the xylanase retained above 50% at pH 6.5 and 8.0, respectively, and near-total losted activity at pH5.0. The temperature-dependent inactivation curve of the T. lanuginosus DSM 10635 xylanase decreased slowly at neutral or slightly alkaline pH, whereas at low pH, the inactivation was rapidly. These favorable properties probably make the T. lanuginosus DSM 10635 xylanase a good candidate for application in industry.