Tyrosinase@HKUST-1: a super stable biocatalyst efficient for catecholic product synthesis

Abstract

Although metal–organic frameworks (MOFs) have been considered as promising matrices for enzyme immobilization, HKUST-1, constructed from copper acetate (CuAc2) and benzene 1,3,5-tricarboxylate (BTC), has rarely been explored for this application. In this study, mushroom tyrosinase (EC 1.14.18.1) was immobilized in the form of tyrosinase@HKUST-1 following a simple reaction procedure by mixing BTC with the enzyme prior to addition of CuAc2. The resultant biocatalyst was characterized in both structural features and catalytic properties. Upon incorporation into the HKUST-1 frameworks, the enzyme gained a prominent enhancement in stability against pH, temperature and storage: When incubated at 50 °C and pH 6.0, tyrosinase@HKUST-1 presented a half-life of 32.6 h, which is 77-fold and over tenfold higher than that of the free enzyme and its other immobilization forms, respectively; and the catalyst fully maintained its activity for at least 2 months when stored at 30 °C. The applicability of this new biocatalyst was demonstrated by employing it as catalyst for regioselective ortho-hydroxylation reactions to produce catecholic products with huge pharmacological effects, i.e., hydroxytyrosol and l-DOPA, with excellent yields and productivities. This study has thus offered a facile immobilization method to prepare a novel biocatalyst with super stability, and tyrosinase@HKUST-1 so formed from crude mushroom extract provides an efficient catalyst which can be applied to the production of catecholic products with health benefits. Graphical Abstract

Current trends in the synthesis, characterization and application of metal-organic frameworks

“…This served as a biocatalyst for regioselective ortho-hydroxylation reactions to produce catecholic products with huge pharmacological effects, i.e., hydroxytyrosol and L-DOPA, with excellent yields and productivities and stability. 176 Other recent studies in this section have been documented by Huang et al 177 5.2.3 Photocatalysts. A photocatalyst is a material which absorbs light to bring it to a higher energy level and provides such energy to a reacting substance to make a chemical reaction occur.…”

“…, hydroxytyrosol and l -DOPA, with excellent yields and productivities and stability. 176 Other recent studies in this section have been documented by Huang et al 177…”

Enzyme-Immobilized Porous Crystals for Environmental Applications

“…Tyrosinase is another copper-containing oxidoreductase capable of utilizing atmospheric oxygen as an oxidant, enabling the biocatalytic oxidation of harmful pollutants without the addition of other reagents. Yang’s group encapsulated mushroom tyrosinase into ZIF-8 and HKUST-1 using an in situ encapsulation method. The tyrosinase hybrid biocatalyst demonstrated excellent tolerance to variations in pH and temperature, efficiently removing typical phenolic pollutants and bisphenols in complex environments.…”

Recent advances in fungal xenobiotic metabolism: enzymes and applications

“…For example, Patil et al ( 2021 ) reported that the main metabolite arising from chloropyrifos biotransformation in Trametes hirsuta MTCC-1171 is 2,4-bis (1,1 dimethylethyl) phenol, which is an important fuel additive. Lu et al ( 2021 ) demonstrated that mushroom tyrosinase immobilised in a metal-organic framework (MOF) was a much-improved biocatalyst compared with the non-immobilised enzyme for production of the pharmacologically important catechols L-DOPA and hydroxytyrosol.…”