Properties of recombinant endo-β-1,6-glucanase from Trichoderma harzianum and its application in the pustulan hydrolysis.

The gene encoding Trichoderma harzianum fungus pustulanase (ThBGL1.6, GH5 family, endo-β-1,6-glucanase, EC 3.2.1.75) was cloned and heterologously expressed by the highly productive Penicillium verruculosum fungus. The recombinant ThBGL1.6 was purified and its properties were studied. The ThBGL1.6 had an observed molecular mass of 46 kDa (SDS-PAGE data) and displayed maximum of the enzyme activity at pH 5.0 and 50 °C. At 45 °C, the ThBGL1.6 was stable for at least 3 h. The K _m was 1.0 g/L with pustulan as the substrate. Reaction product analysis by HPLC clearly indicated that ThBGL1.6 has an endo-hydrolytic mode of action against pustulan as specific substrate. It was also identified that gentiobiose is the main reaction product at studying of long-term pustulan hydrolysis.
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