Gene cloning and biochemical properties of Thermomyces lanuginosus exo-β-glucanase

Abstract:

[Objective] Thermophilic filamentous fungus Thermomyces lanuginosus is capable of secreting a host of thermostable enzymes. We are committed to find a high activity and thermostable β-glucanase gene. [Mehtods] a novel exo-β-glucanase gene (glnB) was cloned from T. lanuginosus and successfully expressed in Pichia pastoris GS115. [Results] SDS-PAGE shows that GlnB has a molecular weight of about 48 kD. Levels of recombinant GlnB reached 11.5 U/mL in the flask fermentation broth of recombinant Pichia cells. GlnB exhibited optimum temperature and pH at 65 °C and 5.0, respectively, and was stable below 50 °C and over the pH range 3.0?10.0. Hydrolysis of laminarin by the recombinant GlnB produced monosaccharide and disaccharide, and extended incubation resulted in partial hydrolysis of disaccharide. [Conclusion] The recombinant enzyme GlnB from T. lanuginosus is an exo-β-glucanase and has good command of thermo stability and pH stability.