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CotA laccase immobilized on functionalized magnetic graphene oxide nano-sheets for efficient biocatalysis

2017; Elsevier BV; Volume: 445; Linguagem: Inglês

10.1016/j.mcat.2017.12.004

2468-8274

Nadia A. Samak, Yeqiang Tan, Kunyan Sui, Tingting Xia, Kefeng Wang, Chen Guo, Chunzhao Liu,

Electrochemical sensors and biosensors

In this work, a novel type of functionalized magnetic graphene oxide (MGO) nano-sheets which have the ability to capture His-tagged CotA laccase was synthesized. Nα,Nα-Bis(carboxymethyl)-l-lysine hydrate (NTA-NH2) was attached on MGO then chelated with Ni2+ and Cu2+ separately. The Cu2+-chelated MGO (MGO-NTA-Cu2+) exhibited the highest adsorption capacity of 177 mg/g-support when compared with both MGO and Ni2+-chelated MGO (MGO-NTA-Ni2+) which exhibited an adsorption capacity of 49.9 and 145 mg/g-support, respectively. CotA laccase immobilized on MGO-NTA-Cu2+ nano-sheets showed the highest activity recovery when compared with that immobilized on MGO-NTA-Ni2+ nano-sheets. The catalytic properties of MGO-NTA-Cu-CotA laccase were significantly improved in comparison with those of the free laccase. MGO-NTA-Cu-CotA laccase showed efficient decolorization for Congo Red (CR), and the decolorization rate reached 100% after 5 h reaction at 60 °C and pH 8. Furthermore, MGO-NTA-Cu-CotA laccase retained 89.4% of its initial activity after 10 consecutive cycles. Together these results indicated that the Cu2+ chelated MGO nano-sheets are promising support for efficient CotA laccase immobilization for environmental and industrial applications under high temperature and alkaline condition.