丝状真菌Amorphotheca resinae ZN1的糠醛降解代谢分析

Furfural degradation by filamentous fungus Amorphotheca resinae ZN1

摘要:

木质纤维素在预处理过程产生的降解产物对后续的酶水解和微生物发酵过程产生了强烈的抑制。因此，这些抑制物的脱除即所谓的“脱毒”步骤是正常进行后续酶解和发酵的前提条件。我们对本实验室筛选的丝状真菌Amorphotheca resinae ZN1的糠醛的代谢路径进行了研究。丝状真菌A. resinae ZN1转化糠醛的降解代谢途径可以简述为：糠醛首先快速地转化为毒性较低的糠醇；在有氧条件下，糠醇又再度生成不致对微生物产生危害的低浓度糠醛，糠醛继续氧化为糠酸。推测糠酸可能继续进入TCA循环，进而完成糠醛的完全降解。研究结果为将来加快丝状真菌A. resinae ZN1生物脱毒速率、改善木质纤维素生物转化的限速步骤提供了重要的实验依据。

Abstract:

Some degradation products from lignocellulose pretreatment strongly inhibit the activities of cellulolytic enzymes and ethanol fermentation strains, thus the efficient removal of the inhibitor substances (“detoxification”) is the inevitable step for the biotransformation processes. In this study, the biological detoxification of furfural by a newly isolated fungus, Amorphotheca resinae ZN1, was studied and the metabolic pathways of furfural degradation was analyzed. The metabolic pathway of furfural degradation in A. resinae ZN1 was described as follows: first, furfural was quickly converted into the low toxic furfuryl alcohol; then the furfuryl alcohol was gradually converted into furfural again but under the low concentration under aerobic condition, which was not lethal to the growth of the fungi; furfural continued to be oxidized to furoic acid by A. resinae ZN1. It is likely that furoic acid was further degraded in the TCA cycle to complete the biological degradation of furfural. The present study provided the important experimental basis for speeding up the biodetoxification of furfural by A. resinae ZN1 and the rate-limiting step in the lignocellulose biotransformation to ethanol.