灰树花漆酶的酶学性质及其脱色作用研究

Decoloration Effect of Dye and Enzymatic Characteristics on Laccase from Grifola Frondosa

通过对液体发酵灰树花漆酶的酶活、Km常数、温度和p H值的测定,探讨了Cu2＋、Fe3＋、Ca2＋对漆酶酶活的影响,观察了漆酶对5种染料的脱色作用效果。结果表明：灰树花发酵液中漆酶氧化ABTS的Km为1.35×10-5mol·L-1,在p H值2~6的范围内均表现酶活,最适p H值为3.0,在25~70℃温度时范围内均有酶活,在50~55℃时酶活性最高。Cu2＋、Fe3＋、Ca2＋对漆酶的活性均有抑制作用,Ca2＋离子的抑制作用较弱。灰树花漆酶对甲基橙、甲基红、溴甲酚绿、甲基蓝和亚甲基蓝染料的脱色率分别为85.77%,81.10%,72.68%,22.02%和4.22%。介体ABTS对漆酶处理甲基蓝的脱色有促进效果,而对亚甲基蓝、溴甲酚绿和甲基红的脱色促进效果较弱,对甲基橙的脱色无促进作用。结论：本研究中灰树花漆酶最适p H值为3.0,在50~55℃时酶活性最高;灰树花漆酶对甲基橙、甲基红、溴甲酚绿染料的脱色效果理想。

The enzymatic activity, Km constant, reaction temperature and pH of laccase from submerged fermentation of Grifola frondosa were assayed. The effect of Cu2＋ , Fe3 ＋ , Ca2 ＋ on laccase activity were analyzed, and decoloration effect of laccase on 5 kinds of dyes was observed. The Km of laccase was 1.35×10 -5 mol · L-1. Laccase showed activity within the range of 20 ~ 70℃ and the optimum temperature was 50 ~ 55 ℃, within the range of pH 2 - 6 and the suitable pH was 3.0. The enzymatic activity of laccase was inhibited in different extent by Cu2 ＋ , Fe3 ＋ and Ca2＋. During the decoloration of methyl orange, methyl red, bromocresol green, methylene blue and methylthionine chloride dyes with laccase, the decoloration rate was 85.77%, 81.10%, 72.68%, 22.02% and 4.22% respectively. The decoloration effect of laccase was accelerated while the ABTS was added into the methylene blue dye solution. There was weak accelerated decoloration effect of laccase adding the ABTS into methyl red, bromocresol green, methylthionine chloride dyes, and no accelerated decoloration effect adding ABTS into methyl orange dye. Conclusion ： The optimum reaction temperature and pH of laccase from Grifola frondosa was 50 ~ 55 ℃ and 3.0. The significant decoloration effect were observed when the methyl orange, methyl red, bromocresol green dyes was dealt with laccase.