University of British Columbia, Vancouver, BC, Canada.
Appl Microbiol Biotechnol. 2012 Apr;94(2):323-38. doi: 10.1007/s00253-012-3954-y. Epub 2012 Mar 6.
This work reviews the brown-rot fungal biochemical mechanism involved in the biodegradation of lignified plant cell walls. This mechanism has been acquired as an apparent alternative to the energetically expensive apparatus of lignocellulose breakdown employed by white-rot fungi. The mechanism relies, at least in the incipient stage of decay, on the oxidative cleavage of glycosidic bonds in cellulose and hemicellulose and the oxidative modification and arrangement of lignin upon attack by highly destructive oxygen reactive species such as the hydroxyl radical generated non-enzymatically via Fenton chemistry [Formula: see text]. Modifications in the lignocellulose macrocomponents associated with this non-enzymatic attack are believed to aid in the selective, near-complete removal of polysaccharides by an incomplete cellulase suite and without causing substantial lignin removal. Utilization of this process could provide the key to making the production of biofuel and renewable chemicals from lignocellulose biomass more cost-effective and energy efficient. This review highlights the unique features of the brown-rot fungal non-enzymatic, mediated Fenton reaction mechanism, the modifications to the major plant cell wall macrocomponents, and the implications and opportunities for biomass processing for biofuels and chemicals.
本文综述了褐腐真菌在木质素植物细胞壁生物降解过程中的生化机制。该机制是对白色腐真菌采用的木质纤维素分解的高能效设备的一种明显替代。该机制至少在腐朽的初始阶段依赖于纤维素和半纤维素糖苷键的氧化裂解，以及木质素的氧化修饰和排列，这些修饰和排列是由高度破坏性的氧反应性物质（如通过芬顿化学[公式：见正文]非酶促产生的羟基自由基）攻击所致。与这种非酶促攻击相关的木质纤维素宏观成分的修饰被认为有助于通过不完全的纤维素酶套件选择性地、近乎完全地去除多糖，而不会导致木质素的大量去除。利用这一过程可能是使木质纤维素生物质生产生物燃料和可再生化学品更具成本效益和能源效率的关键。本文重点介绍了褐腐真菌非酶促介导的芬顿反应机制的独特特征、主要植物细胞壁宏观成分的修饰以及对生物燃料和化学品生物量加工的影响和机会。
