DELIGNIFICATION BY WOOD-DECAY FUNGI
DELIGNIFICATION BY WOOD-DECAY FUNGI
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DOI：
10.1146/annurev.py.29.090191.002121
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发表时间：
1991-01-01
影响因子：
10.2
通讯作者：
BLANCHETTE, RA
中科院分区：
文献类型：
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作者：
BLANCHETTE, RA
木材腐烂真菌是独一无二的，因为它们能够分解木质化的细胞壁。有几种植物特别令人感兴趣，因为它们可以选择性地去除木材中的木质素，而不会大量降解纤维素。木质素是一种复杂的、非均相的苯丙烷类结构聚合物，存在于整个细胞壁(71,112)。在空间上，木质素与半纤维素紧密地穿插在一起，形成了围绕着纤维素微纤维(67，75)的基质，并为生物降解系统提供了强大的物理和化学屏障。虽然大多数腐生真菌产生一些降解酶，如纤维素酶、木聚糖酶、甘露聚糖酶等，但这些酶不能有效地渗透和降解木质底物，除非木质素被解离、修饰或去除。对森林生态系统中分解过程的研究通常认为木质素是最顽固的成分，最后被降解(10，88)。担子菌纲中的一些真菌腐烂的分解途径，如那些引起褐腐病的真菌，涉及所有木材碳水化合物的降解，包括结晶纤维素。残留的木质素基质由化学修饰的木质素组成，通过涉及其他微生物的长期过程逐渐转化为腐殖质(38、41、106)。然而，这并不总是事件的顺序。担子菌属中引起木材白腐病的真菌可以同时降解木质素和所有细胞壁碳水化合物或木质素。
Wood decay fungi are unique because of their capacity to decompose lignified cell walls. A few species are of special interest because they can selectively remove lignin from wood without extensive cellulose degradation. Lignin is a complex, heterogeneous phenylpropanoid structural polymer that occurs throughout the cell wall (71, 112). Spatially, lignin is intimately interspersed with hemicelluloses forming a matrix that surrounds cellulose microfibrils (67, 75), and provides a formidable physical and chemical barrier to biodeg radative systems. Although most saprophytic fungi produce some degradative enzymes, such as cellulases, xylanases, mannanases and others, these en zymes do not permeate and degrade effectively woody substrates unless lignin is unbound, modified, or removed.Investigations of decomposition processes in forest ecosystems have usual ly considered lignin to be the most recalcitrant component and the last degraded (l0, 88). The decomposition pathway for decay by some fungi in the Basidiomycotina, such as those that cause brown rots, involves the degradation of all wood carbohydrates, including crystalline cellulose. A residual lignin matrix, consisting of chemically modified lignin, is left to be gradually converted to humic substances by long-term processes involving other microbes (38, 41, 106). However, this is not always the sequence of events. Fungi in the Basidiomycotina that cause white rots of wood may simultaneously degrade lignin along with all cell wall carbohydrates, or lignin