Enzymatic-photocatalytic synergetic effect on the decolorization of dyes by single chloroperoxidase molecule immobilization on TiO2 mesoporous thin film

Publication date: 5 September 2017
Source:Materials & Design, Volume 129
Author(s): Jing Lu, Long Cheng, Yong Wang, Yu Ding, Mancheng Hu, Shuni Li, Quanguo Zhai, Yucheng Jiang
A chloroperoxidase (CPO) -TiO2 thin film type enzyme reactor was constructed by single chloroperoxidase molecule immobilization on TiO2 mesoporous thin film. The CPO-TiO2 enzyme reactor showed an enzymatic-photocatalytic synergetic effect, 1+1>2, when applied in the decolorization of azo dye crocein orange G. Moreover, the enzyme reactor made it possible that the photocatalytic catalysis was carried out under natural sunlight instead of ultraviolet radiation. The synergetic effect was studied by PL emission spectroscopy with terephthalic acid used as a probe molecule to investigate the formation of ·OH radicals.The mesoporous TiO2, prepared by a sol-gel and dip-coating method, being spherical form without interconnectivity in a 3D pore systems of 8nm ~15nm pore size, matched the size of CPO molecules. Such an architecture was suitable for single CPO molecule immobilization, which enabled easy access of the substrates to enzyme active sites.The CPO-TiO2 enzyme reactor was very efficient. 98.61% decolorization efficiency of crocein orange G was achieved in 5min. It can be reused for seven cycles with no loss in activity. Compared with free CPO, the stability of CPO-TiO2 enzyme reactor against thermal denaturation and deactivation by high concentration of oxidants or in a strong acid-base environment was enhanced.

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