白囊耙齿菌产锰过氧化物酶条件优化及其对染料的脱色

锰过氧化物酶（manganese peroxidase,MnP）是白腐真菌降解多种异生物质的主要降解酶之一。本研究对白囊耙齿菌Irpex lacteus产MnP的酶活曲线进行监测,利用单因素和正交试验对I. lacteus产MnP的发酵条件进行优化,同时检测了I. lacteus的MnP粗酶液对5种染料的脱色效果。结果显示,I. lacteus在培养5d时MnP活性较大;I. lacteus产MnP较优的条件为：可溶性淀粉20g/L、尿素1g/L、pH 6.3、CaCl₂ 1mmol/L、FeCl₃ 1mmol/L,该条件下MnP活性达29.24U/L,与优化前MnP活性相比提高了1.25倍;I. lacteus的MnP粗酶液对5种染料均可脱色,其中对直接大红和活性红的脱色效果更为明显,脱色5d后的脱色率分别达到82%和81%。

Optimization of Irpex lacteus culture conditions for manganese peroxidase production and dye decolorization ability of the enzyme

Manganese peroxidase (MnP), one of the key enzymes secreted by white rot fungi, can degrade various xenobiotics efficiently. In the present study, the activity curve of MnP activity from Irpex lacteus was measured. The fermentation conditions of I. lacteus producing MnP were optimized using single factor and orthogonal experiments. Extracellular solutions of MnP were used to decolor five kinds of dye. The results showed that the MnP activity of I. lacteus was highest at day 5 of culture. The most optimal culture parameters for MnP production were soluble starch 20g/L, urea 1g/L, CaCl₂ 1mmol/L, FeCl₃ 1mmol/L, and pH 6.3. The MnP activity reached 29.24U/L after 5 days of culture, 1.25 times higher than that before optimization. The decolorization test showed that extracellular solutions of MnP from I. lacteus could decolor five types of dye. The decolorization effect against direct red and reactive red was particularly obvious, with decolorization rates of 82% and 81%, respectively, after 5 days of decoloration.