Green synthesis of Agaricus avensis-mediated silver nanoparticles for improved catalytic efficiency of tyrosine hydroxylase towards potential biomedical implications

The present study deals with the bio-fabrication of AgA-AgNPs utilizing edible mushroom Agaricus arvensis as a reductant for improved stability and catalytic efficiency towards L-dopa production. The parameters optimized for achieving maximum tyrosine hydroxylase (TH) activity were the mushroom biomass (2.5%, w/v), media for extraction (peptone-saline), and temperature (90 ℃). The activity of tyrosine hydroxylase (TH) was enhanced by its immobilization on AgNPs. The change in color from light yellow to dark brown confirmed the formation of AgA-AgNPs. In addition, the UV–Vis spectrum showed a surface plasmon resonance band at 260 nm. Fourier transform infrared (FTIR) indicated presence of functional groups, which play an important role in production of NPs. X-ray diffraction (XRD) confirmed the crystalline nature of mycosynthesized AgNPs and showed peaks corresponding to 38.8° (111), 46.5° (200), 64.1° (220), and 77.5^o (311). AgA-AgNPs exhibited −9.16 mv zeta potential. Scanning Electron Microscopy (SEM) images of AgA-AgNPs confirmed particle size between 88.49 ± 3.83 nm. Immobilized TH extracted from A. arvensis showed reusability at optimized temperature (20 ℃) for 3 cycles. A 2.54-fold higher production of L-dopa was examined with AgA-AgNPs. Furthermore, immobilized TH consumed more L-tyrosine i.e. 0.554 ± 0.022 mg/ml as compared to the free enzyme at 90 min of biotransformation. Hence, the immobilization of A. arvensis extracted TH on AgNPs increased its activity as well as its stability and catalytic efficiency. AgA-AgNPs has a potential of dopamine synthesis and can play a significant role in drug delivery or biomedical applications.