Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA.
Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, 1084 Columbia Ave, Riverside, CA, 92507, USA.
Sci Rep. 2018 Jan 22;8(1):1350. doi: 10.1038/s41598-018-19848-3.
Amphiphilic additives such as bovine serum albumin (BSA) and Tween have been used to improve cellulose hydrolysis by cellulases. However, there has been a lack of clarity to explain their mechanism of action in enzymatic hydrolysis of pure or low-lignin cellulosic substrates. In this work, a commercial Trichoderma reesei enzyme preparation and the amphiphilic additives BSA and Tween 20 were applied for hydrolysis of pure Avicel cellulose. The results showed that these additives only had large effects on cellulose conversion at low enzyme to substrate ratios when the reaction flasks were shaken. Furthermore, changes in the air-liquid interfacial area profoundly affected cellulose conversion, but surfactants reduced or prevented cellulase deactivation at the air-liquid interface. Not shaking the flasks or adding low amounts of surfactant resulted in near theoretical cellulose conversion at low enzyme loadings given enough reaction time. At low enzyme loadings, hydrolysis of cellulose in lignocellulosic biomass with low lignin content suffered from enhanced enzyme deactivation at the air-liquid interface.
两亲性添加剂，如牛血清白蛋白（BSA）和吐温，已被用于提高纤维素酶对纤维素的水解作用。然而，对于它们在酶解纯或低木质素纤维素底物中的作用机制，还缺乏明确的解释。在这项工作中，使用了一种商业里氏木霉酶制剂和两亲性添加剂 BSA 和吐温 20 来水解纯 Avicel 纤维素。结果表明，只有在酶与底物比例较低且反应瓶摇动时，这些添加剂才会对纤维素转化率产生较大影响。此外，气-液界面面积的变化会显著影响纤维素的转化率，但表面活性剂会降低或阻止在气-液界面上的纤维素酶失活。如果不摇动烧瓶或只添加少量表面活性剂，在足够的反应时间内，即使酶用量低，也会导致纤维素几乎完全转化。在低酶用量下，木质纤维素生物质中低木质素含量的纤维素水解会因在气-液界面上增强的酶失活而受到影响。
