突变灰盖鬼伞过氧化物酶降解刚果红的响应面法优化分析

Optimization of degradation of Congo red by mutant Coprinus cinereus peroxidase using response surface methodology

酶法降解偶氮染料刚果红是一个复杂的过程,受温度、pH、酶量、刚果红浓度和双氧水浓度显著影响。为研究各因素及因素间交互作用对刚果红降解影响,提高刚果红的降解率,分别使用单因素法和响应面分析法对刚果红降解条件进行了优化。单因素实验结果显示灰盖鬼伞过氧化物酶降解刚果红的最适条件为:pH 5.0、32℃、酶量4.98 U、双氧水0.1mmol/L、刚果红20 mg/L,此时刚果红最高降解率为34.84%。然后选双氧水浓度、刚果红浓度和灰盖鬼伞过氧化物酶量作为3个因素,通过中心组合设计实验,用响应面法对刚果红降解进行优化分析,最后得到一个拟合度良好的二次多项方程模型(R2=0.9900)。方差分析结果显示,刚果红浓度和酶量是影响最显著的因素,双氧水与酶以及染料与酶之间的交互作用极显著。响应面分析优化后的反应体系为:双氧水浓度0.15 mmol/L,刚果红浓度为27.21 mg/L,酶为2.0 7 U,在此条件下,刚果红降解率达58.13%。

Enzymatic degradation of the azo dye, Congo red by Coprinus cinereus peroxidease （CIP） is a complex process, which is greatly affected by pH, temperature, enzyme activity, the concentration of hydrogen peroxide （H2OE） and dye. This work aimed to study these factors and to investigate the combined interactions between them by applying conventional one-factor-at-a-time （OFAT） method and response surface methodology （RSM） for degradation of Congo red with mutant CIP. Through the OFAT method the optimum conditions for degradation of Congo red were 32~℃ , pH 5.0, 0. 1 mmol/L of H/O2, 20 mg/L of Congo red and 4.98 U CIP. Under these conditions, the degradation rate reached 34.84%. Moreover, in order to optimize the reaction con- ditions of degradation system, the H2O2 concentration, the CIP activity and the congo red concentration were se- lected as three factors for systematical analysis. Response surface analysis was conducted through central compos- ite design and a reduced cubic model with a good fit of regression equation（Rz = 0. 9900） was generated. ANO- VA analysis of this model indicated that the Congo red concentration, the CIP activity, their interaction and the combined interaction between H202and CIP were the most significant on degradation of Congo red. The optimum conditions through RSM were found to be initial Congo red concentration of 27.21 mg/L, 2.0 7 U CIP, 0. 15 mmol/L of H2O2, for the maximum degradation of 58.13%.