杂色云芝生物预处理对硬木和软木酶水解的影响

Effect of biological pretreatment with Trametes vesicolor on the enzymatic hydrolysis of softwood and hardwood

摘要:

节能减排的生物预处理技术是促进木质纤维素酶水解转化乙醇的有效途径。本试验首次研究了白腐菌杂色云芝(Trametes vesicolor)生物预处理对柳木(Salix babylonica, 硬木)和杉木(Cunninghamia lanceolata, 软木)纤维素酶水解的影响及作用机制。结果显示生物预处理使硬木和软木的最终转化率分别增加4.78倍和4.02倍。通过研究酶与基质的相互作用发现, 预处理后木材基质与酶亲和力的增强并不一定导致酶水解初始转化率的提高; 但水解过程中转化速率的下降速度随着解吸附指数增加而降低, 说明生物处理主要通过减少纤维素酶对基质的不可逆吸附, 延缓水解过程中基质转化速率的急剧下降, 从而提高水解效率。不可逆吸附的降低与预处理过程中木质素的部分降解与改性有一定关系。

Abstract:

We evaluated the effect of biological pretreatment with white rot fungus Trametes vesicolor on the enzymatic hydrolysis of two wood species, Chinese willow (Salix babylonica, hardwood) and China-fir (Cunninghamia lanceolata, softwood). The result indicated that the pretreated woods showed significant increases in the final conversion ratios of enzymatic hydrolysis (4.78-fold for hardwood and 4.02-fold for softwood). In order to understand the role of biological pretreatment we investigated the enzyme-substrate interactions. Biological pretreatment enhanced the substrate accessibility to cellulase but not always correlated with the initial conversion rate. However, the change of the conversion rate decreased dramatically with increased desorption values after biological pretreatment. Thus, the biological pretreatment slowed down the declines in conversion rates during enzymatic hydrolysis by reducing the irreversible adsorption of cellulase and then improved the enzymatic hydrolysis. Moreover, the decreases of the irreversible adsorption may be attributed to the partial lignin degradation and alteration in lignin structure after biological pretreatment.