Agaricus arvensis extract-coated functionalized silver nanoparticles for effective aerobic biotransformation of synthetic L-tyrosine to L-DOPA.

This study presents a green nanobiotechnological platform for enhanced L-DOPA biosynthesis. Intracellular tyrosine hydroxylase (TH) was immobilized onto silver nanoparticles (AgNPs) biosynthesized using extract of the edible mushroom Agaricus arvensis and subsequently applied for the aerobic biotransformation of synthetic L-tyrosine. The AgNPs were produced using the mushroom extract as a natural reducing agent and optimized for "TH" activity under controlled conditions: 2.5% (w/v) biomass concentration, peptone-saline medium, 90 °C, and 24 min reaction time. Various analytical techniques such as UV-Vis spectroscopy, SEM, FTIR and XRD were used to confirm the synthesis and characterization of the AgNPs. The particle size was further validated by Scanning Electron Microscopy (SEM), revealing an average size of 88.49 ± 3.83 nm. The particle size was further analyzed by a Zeta-sizer, which showed a Z-average size of 163.7 d.nm. When applied in the biotransformation of synthetic L-tyrosine, the AgNP-immobilized enzyme significantly outperformed the free enzyme, yielding a 2.54-fold increase in L-DOPA production within 1.5 h. These results indicate that Agaricus arvensis-derived AgNPs not only stabilize the enzyme but also boost its activity, providing a sustainable and efficient approach for producing L-DOPA. This method holds promise for large-scale applications in pharmaceutical manufacturing.