Biotechnology Bulletin ›› 2021, Vol. 37 ›› Issue (6): 244-258.doi: 10.13560/j.cnki.biotech.bull.1985.2020-1205

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Advances in the Application of Immobilized Fungal Laccase for the Bioremediation of Environmental Organic Contamination

CHEN Ming-yu(), NI Xuan, SI You-bin, SUN Kai()   

  1. Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention,School of Resources and Environment,Anhui Agricultural University,Hefei 230036
  • Received:2020-09-23 Online:2021-06-26 Published:2021-07-08
  • Contact: SUN Kai E-mail:1308830389@qq.com;sunkai@ahau.edu.cn

Abstract:

The total discharged amount of organic wastewater in China is huge,and its release into the ecological environments causes a serious threat to the health of wild animals and humans. Bioremediation technology attracts much concerns because it is green,economic and efficient. Laccase catalyzes the oxidative coupling and decomposition of varied organic pollutants in water and this reaction has several advantages such as simple operation,controllable condition,high catalytic efficiency,broad substrate spectrum,and environmental friendliness. Free laccase is unstable and difficult to be recycled,while immobilization technology can improve the catalytic efficiency,operational stability,and reusability of enzyme. Thus,it is expected to have the large-scale applications of laccase in the environmental bioremediation. This paper reviews the molecular structure,substrate spectrum,and catalytic properties of fungal laccase,clarifies the advantages and disadvantages of four conventional immobilization approaches of laccase such as adsorption,entrapment,covalent bonding,and cross-linking. Further this paper emphatically summarizes the radical coupling and oxidative decomposition mechanisms of immobilized laccase-mediated estrogens,antibiotics,polycyclic aromatic hydrocarbons,personal care products,synthetic dye,and sulfa drugs. Immobilized laccase catalyzes the oxidation of organic contaminants to radical and/or quinone intermediates only using molecular oxygen as an electron acceptor. These reactive intermediates not only can covalently couple to form oligomers and polymers,but yield decomposition products by radical-initiated attack each other,thereby reducing the bioavailability and biotoxicity of the parent compounds. Immobilized laccase shows a huge potential in the purification of organic wastewater,elimination of environmental pollution,and maintenance of ecological health. However,it is necessary to further screen the inexpensive immobilized carriers and improve the recycling rate of immobilized laccase.

Key words: immobilized laccase, catalytic mechanism, organic contamination, environmental remediation