木腐真菌分泌的低分子量物质在木质纤维素生物降解过程中作用机制的研究

Function of the Iron-binding Chelator Produced by Coriolus Versicolor in Native Lignocellulose Biodegradation

从杂色云芝(Coriolus versicolor)培养基中分离到一类低分子量组分,该组分具有螯合Fe3+的能力,并能够将Fe3+还原为Fe2+,推测该组分可能是Fenton反应中的一类电子传递体。采用三倍体毛白杨作为研究对象,设计对照,用SEM、AFM等手段检测了低分子量物质与酶协同对木材的作用。实验结果表明,低分子量物质和大分子的酶类协同作用能够破坏致密的木质纤维结构,形成较小的木纤片段,更利于酶进行进一步的降解,推测这类低分子量物质在木材降解的初期具有重要的生物学功能。

An ultrafiltered low-molecular-weight preparation of chelating compounds was isolated from a wood-containing culture of the white-rot basidiomycete Coriolus versicolor.This preparation could chelate Fe^3＋ and reduce Fe^3＋ to Fe^2＋,demonstrating that the substance may serve as a ferric chelator,oxygen-reducing agent,and redox-cycling molecule,which would include functioning as the electron transport carrier in Fenton＇s reactions.The effects on native wood of the low-molecular-weight compounds and ligninolytic enzymes were estimated on the SEM,AFM methods.The images showed that the iron-binding chelator and the lignocellulolytic enzymes can destroy the compact structure of wood.It was believed that the synergic effects of the iron-binding chelator and enzymes could split the fibers of the aspen slice.The smaller fragments were more accessible for degradation by the enzymes.Furthermore,the holes in the aspen slice after treatment could allow the large enzyme molecules to penetrate into the cell wall.Thus,we proposed the hypothesis that the iron-binding chelator may initiate the breakdown of natural lignocellulose.