Department of Bioresource & Environmental Security, Sandia National Laboratories, 7011 East Avenue, Livermore, CA 94551, USA.
Deconstruction Division, Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA.
Biomolecules. 2024 Mar 8;14(3):324. doi: 10.3390/biom14030324.
Laccases from white-rot fungi catalyze lignin depolymerization, a critical first step to upgrading lignin to valuable biodiesel fuels and chemicals. In this study, a wildtype laccase from the basidiomycete (Fom_lac) and a variant engineered to have a carbohydrate-binding module (Fom_CBM) were studied for their ability to catalyze cleavage of β-O-4' ether and C-C bonds in phenolic and non-phenolic lignin dimers using a nanostructure-initiator mass spectrometry-based assay. Fom_lac and Fom_CBM catalyze β-O-4' ether and C-C bond breaking, with higher activity under acidic conditions (pH < 6). The potential of Fom_lac and Fom_CBM to enhance saccharification yields from untreated and ionic liquid pretreated pine was also investigated. Adding Fom_CBM to mixtures of cellulases and hemicellulases improved sugar yields by 140% on untreated pine and 32% on cholinium lysinate pretreated pine when compared to the inclusion of Fom_lac to the same mixtures. Adding either Fom_lac or Fom_CBM to mixtures of cellulases and hemicellulases effectively accelerates enzymatic hydrolysis, demonstrating its potential applications for lignocellulose valorization. We postulate that additional increases in sugar yields for the Fom_CBM enzyme mixtures were due to Fom_CBM being brought more proximal to lignin through binding to either cellulose or lignin itself.
白腐真菌来源的漆酶能够催化木质素解聚，这是将木质素升级为有价值的生物柴油燃料和化学品的关键第一步。在这项研究中，研究了一种来自担子菌 （Fom_lac） 的野生型漆酶和一种经过工程改造以具有碳水化合物结合模块（Fom_CBM）的变体，以研究它们在使用基于纳米结构引发质谱的测定法时催化酚类和非酚类木质素二聚体中β-O-4'醚和 C-C 键断裂的能力。Fom_lac 和 Fom_CBM 催化β-O-4'醚和 C-C 键断裂，在酸性条件下（pH < 6）具有更高的活性。还研究了 Fom_lac 和 Fom_CBM 对未经处理和离子液体预处理松木的糖化产率的增强潜力。与向相同混合物中添加 Fom_lac 相比，将 Fom_CBM 添加到纤维素酶和半纤维素酶混合物中可将未经处理的松木的糖产量提高 140%，并将胆碱赖氨酸预处理的松木的糖产量提高 32%。向纤维素酶和半纤维素酶混合物中添加 Fom_lac 或 Fom_CBM 都能有效地加速酶水解，这表明它在木质纤维素增值方面具有潜在的应用。我们假设，Fom_CBM 酶混合物的糖产量增加更多是由于 Fom_CBM 通过与纤维素或木质素本身结合而更接近木质素。
