| Summary: | <i>Beauveria bassiana</i> is an entomopathogenic fungus widely used as a biopesticide for insect control; it has also been shown to exist as an endophyte, promoting plant growth in many instances. This study highlights an alternative potential of the fungus; in the production of an industrially important biocatalyst, xylanase. In this regard, <i>Beauveria bassiana</i> SAN01 xylanase was purified to homogeneity and subsequently characterized. The purified xylanase was found to have a specific activity of 324.2 U·mg<sup>−1</sup> and an estimated molecular mass of ~37 kDa. In addition, it demonstrated optimal activity at pH 6.0 and 45 °C while obeying Michaelis–Menton kinetics towards beechwood xylan with apparent <i>K<sub>m</sub></i>, V<sub>max</sub> and <i>k<sub>cat</sub></i> of 1.98 mg·mL<sup>−1</sup>, 6.65 μM·min<sup>−1</sup> and 0.62 s<sup>−1</sup> respectively. The enzyme activity was strongly inhibited by Ag<sup>2+</sup> and Fe<sup>3+</sup> while it was significantly enhanced by Co<sup>2+</sup> and Mg<sup>2+</sup>. Furthermore, the xylanase was shown to effectively deink wastepaper at an optimal rate of 106.72% through its enzymatic disassociation of the fiber-ink bonds as demonstrated by scanning electron microscopy and infrared spectroscopy. This is the first study to demonstrate the biotechnological application of a homogeneously purified glycosyl hydrolase from <i>B</i><i>. bassiana.</i>
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