Novel Laccase Biosensors from Manihot Esculenta, Crantz -Associated Fungi: A Biotechnological Approach to Dopamine Quantification

Abstract

This study investigates the association of endophytic fungi with the leaves and stems of cassava (Manihot esculenta Crantz), leading to the isolation and identification of 23 fungal strains. Of these, 18 fungi were associated with stems and 5 with leaves. Subsequent analysis revealed laccase activity in 7 fungi isolates, predominantly within those derived from stems. Notably, the fungus LV2, identified as a strain of Xylaria sp., exhibited the highest laccase activity (0.03 U.mg− 1.min− 1). Optimal LV2 fungus growth and enzyme activity conditions were established at 11 days, pH 6.70, and 29ºC (0.051 U.mg− 1.min− 1). Utilizing the LV2 enzymatic extract, we developed a chitosan-based enzyme biosensor with STMP crosslinking for immobilization to detect low dopamine concentrations. The biosensor demonstrated optimal performance at pH 5.1 and 47.8ºC, achieving a detection limit of 0.30 µmol.L− 1 for dopamine.