铜锰离子添加下奶油栓孔菌的木质素降解酶活性、耐受性及移除能力

Lignin-degrading enzymatic activities,tolerance,and removal ability of Trametes lactinea under the addition of Cu^(2+)and Mn^(2+)

漆酶(Lac)和锰过氧化物酶(MnP)是木质素降解酶系主要成员,不同浓度Cu^(2+)和Mn^(2+)下特定真菌菌株的Lac和MnP活性、金属耐受性与移除能力有待深入探索.以奶油栓孔菌(Trameteslactinea)为材料,通过控制液体培养基初始Cu^(2+)和Mn^(2+)浓度,观测不同浓度铜锰离子对Lac和MnP活性、菌丝体生长、黑色素产量及最终离子浓度的影响.结果显示,Lac活性含Cu^(2+)各处理均优于对照,后20 d高于前20 d.前20 d,0.5和1.0 mmol/L Cu^(2+)诱导效果较好;后20 d,10.0mmol/L的Lac活性最高.2.0、3.0和10.0mmol/LCu^(2+)诱导Lac活性,也抑制菌丝体生长,不过该菌株能降低Cu^(2+)浓度.0.5、0.7和1.0mmol/LMn^(2+)的Lac活性诱导效果相对稳定,2.0、5.0和10.0 mmol/L的波动较大,仅10.0 mmol/L对菌丝体生长有微弱抑制.Cu^(2+)和Mn^(2+)均诱导MnP活性,但MnP活性低.该菌Cu^(2+)胁迫下产生更多黑色素,对Mn^(2+)耐受性较强.0.5-10.0 mmol/L范围内该菌株Cu^(2+)移除能力随初始浓度增加而增强.本研究表明Cu^(2+)和Mn^(2+)都能诱导该菌株产生更强的Lac和MnP活性;该菌株有较好的Cu^(2+)移除能力,对Mn^(2+)耐受性强于Cu^(2+);结果可为木质素降解酶活性诱导、高产漆酶菌株发掘和重金属污染生物修复等提供参考.

Laccase(Lac)and manganese peroxidase(MnP)are the two major lignin-degrading enzymes.Under different concentrations of Cu^(2+)and Mn^(2+),the Lac and MnP activities,metal tolerance,and removal capability of specific fungal strains need further exploration.In this study,a strain of Trametes lactinea was used as a research model to observe the effects of Cu^(2+)and Mn^(2+)on Lac and MnP activity,mycelial growth,melanin production,and final ion concentration by controlling the initial concentrations of Cu^(2+)and Mn^(2+)in the liquid culture medium.The results showed that the Lac activity of each treatment supplemented with Cu^(2+)was greater than that of the control and was higher in the last 20 days than in the first 20 days.In the first 20 days,0.5 and 1.0 mmol/L Cu^(2+)had better induction effects.Lac activity at 10.0 mmol/L was the highest during the last 20 days.Cu^(2+)(2.0,3.0,and 10.0 mmol/L)induced Lac activity and inhibited mycelia growth;however,the strain reduced the Cu^(2+)concentration.For Mn^(2+),the induction effects of 0.5,0.7,and 1.0 mmol/L on Lac activity were relatively stable.However,the activities of 2.0,5.0,and 10.0 mmol/L showed evident fluctuations,and only 10.0 mmol/L weakly inhibited the mycelia growth.Both Cu^(2+)and Mn^(2+)induced MnP activity;however,the MnP activity was low.This strain produced more melanin under Cu^(2+)stress and exhibited strong tolerance to Mn^(2+).The Cu^(2+)removal capacity of the strain increased as the concentration increased from 0.5 to 10.0 mmol/L.In summary,both Cu^(2+)and Mn^(2+)were powerful inducers of Lac and MnP activities in the strain,which could remove Cu^(2+)and was more tolerant to Mn^(2+)than to Cu^(2+).This study provides a reference for the induction of lignin-degrading enzyme activity,the identification of laccase-producing strains,and the bioremediation of heavy metal pollution.