Identification, purification, and biochemical characterization of glucose oxidase from the newly isolated Talaromyces pinophilus 47 K9, an endophytic fungus from Prosopis stephaniana

Endophytic fungi have emerged as valuable reservoirs for discovering bioactive compounds with significant biological properties. In this study, a novel endophytic fungus, Talaromyces pinophilus 47 K9, was isolated from Prosopis stephaniana. The antimicrobial enzyme glucose oxidase was purified from the culture medium of T. pinophilus 47 K9 through a series of techniques, including 70 % ammonium sulfate precipitation, solid-phase extraction, ultrafiltration, ion-exchange chromatography, and gel filtration. The enzyme was identified using SDS-PAGE and proteomic analysis via MS/MS sequencing. Biochemical characterization revealed a molecular weight of 65.8 kDa and an enzymatic activity of 0.71 U/mL when glucose served as a substrate. The glucose oxidase demonstrated broad stability within a pH range of 3 to 10, though it was thermally unstable at temperatures exceeding 60 °C. Substrate specificity tests indicated that glucose served as the optimal substrate for H₂O₂ production, which subsequently improved antimicrobial efficacy. Notably, the glucose oxidase exhibited broad-spectrum antimicrobial activity, effectively inhibiting five Candida species, six phytopathogenic fungi, and both Gram-positive and Gram-negative bacteria. Given its potent antimicrobial properties, high substrate specificity, and stability across diverse conditions, glucose oxidase from T. pinophilus 47 K9 holds potential as a viable alternative antimicrobial agent.