Cascade Conversion of Methyl Parathion to 4-Aminophenol by In Situ Encapsulated Organophosphate Hydrolase within a Reduction-Catalytic Cupric MOF

Detoxification of the typical organophosphate pesticide methyl parathion (MP) is of great significance for environmental remediation and sustainable development. Hydrolysis of MP using organophosphate hydrolase (OPH) is an effective and environmentally friendly way to degrade MP, but the hydrolytic product, 4-nitrophenol (4-NP), is still toxic. The cascade conversion of MP to 4-NP followed by reduction to a low toxic product, 4-aminophenol (4-AP), is thus an attractive way to detoxify MP. Herein, we fabricated a highly active reduction-catalytic cupric metal–organic framework (MOF) (Cu-AZO), which exhibited over 6-fold higher activity than the previous Cu-AZB. Thus, a chemoenzymatic catalyst (OPH/Cu-AZO) for one-pot cascade MP conversion to 4-AP was constructed by in situ immobilization of the OPH in Cu-AZO. OPH/Cu-AZO displayed an enzyme loading capacity of 16–69 mg/g with an activity recovery of up to 252%, and an average cascade conversion rate of up to 41.7 μmol·min –1 ·g catalyst –1 . At the optimized conditions, OPH/Cu-AZO completely converted 50 μM MP to 4-AP within 3 min at a low reductant concentration (10 mM NaBH 4 ) in the one-pot cascade reaction. Moreover, the hybrid catalyst retained 99% activity in 10 days storage and >65% activity in 10 recycles. The results proved that OPH/Cu-AZO was the most efficient chemoenzymatic catalyst reported so far in the cascade conversion of MP to 4-AP, underscoring its potential applications in the detoxification of MP.