title: Degradation and detoxification of the triphenylmethane dye malachite green catalyzed by crude manganese peroxidase from Irpex lacteus F17.
abstract: Malachite green (MG), a recalcitrant, carcinogenic, and mutagenic triphenylmethane dye, was decolorized and detoxified using crude manganese peroxidase (MnP) prepared from the white rot fungus Irpex lacteus F17. In this study, the key factors (pH, temperature, MG, Mn(2+), H2O2, MnP) in these processes were investigated. Under optimal conditions, 96 % of 200 mg L(-1) of MG was decolorized when 66.32 U L(-1) of MnP was added for 1 h. The K m, V max, and k cat values were 109.9 μmol L(-1), 152.8 μmol L(-1) min(-1), and 44.5 s(-1), respectively. The decolorization of MG by MnP followed first-order reaction kinetics with a kinetic rate constant of 0.0129 h(-1). UV-vis and UPLC analysis revealed degradation of MG. Furthermore, seven different intermediates formed during the MnP treatment of 0.5 h were identified by LC-TOF-MS. These degradation products were generated via two different routes by either N-demethylation of MG or the oxidative cleavage of the C-C double bond in MG. Based on ecotoxicity analyses performed on bacteria and algae, it was confirmed that MG metabolites produced by the MnP-catalyzed system were appreciably less toxic than the parent compound. These studies indicate the potential use of this enzyme system in the clean-up of aquatic and terrestrial environments.
authors: School of Life Science, Anhui University, Hefei, 230601, People's Republic of China.
authors: Xueting
authors: X
authors: Yang
authors: School of Life Science, Anhui University, Hefei, 230601, People's Republic of China.
authors: Jinzhao
authors: J
authors: Zheng
authors: School of Life Science, Anhui University, Hefei, 230601, People's Republic of China.
authors: Yongming
authors: Y
authors: Lu
authors: School of Life Science, Anhui University, Hefei, 230601, People's Republic of China. ahdxjiarong@126.com.
authors: Rong
authors: R
authors: Jia
mesh_terms: D004396:Coloring Agents / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D005656:Fungal Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism*; D020072:Polyporales / Q000201:enzymology*; D012394:Rosaniline Dyes / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D018508:Water Purification
chemical_list: D004396:Coloring Agents; D005656:Fungal Proteins; D012394:Rosaniline Dyes; D014874:Water Pollutants, Chemical; C005095:malachite green; D010544:Peroxidases; C051129:manganese peroxidase
keywords: Degradation; Ecotoxicity; Enzymatic decolorization; Kinetics; Malachite green; Manganese peroxidase