Tu Maobing, Pan Xuejun, Saddler Jack N
School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama 36849, USA.
J Agric Food Chem. 2009 Sep 9;57(17):7771-8. doi: 10.1021/jf901031m.
Enzymatic hydrolysis of lignocellulosic materials is significantly affected by cellulase adsorption onto the lignocellulosic substrates and lignin. The presence of lignin plays an important role in lignocellulosic hydrolysis and enzyme recycling. Three cellulase preparations (Celluclast, Spezyme CP, and MSUBC) were evaluated to determine their adsorption onto cellulolytic enzyme lignin (CEL) from steam-exploded Lodgepole pine (SELP) and ethanol (organosolv)-pretreated Lodgepole pine (EPLP). The adsorption affinity of cellulase (Celluclast) onto isolated lignin (CEL-EPLP and CEL-SELP) was slightly higher than that from corresponding EPLP and SELP substrates on the basis of the Langmuir constants. Effects of temperature, ionic strength, and surfactant on cellulase adsorption onto isolated lignin were also explored in this study. Thermodynamic analysis of enzyme adsorption onto isolated lignin (Gibbs free energy change DeltaG(0) approximately -30 kJ/mol) indicated this adsorption was a spontaneous process. The addition of surfactant (0.2% w/v) could reduce the adsorption of cellulase onto CEL-SELP by 60%. Two types of adsorption isotherm were compared for cellulase adsorption onto isolated lignin. A Langmuir adsorption isotherm showed better fit for the experimental data than a Freundlich adsorption isotherm.
木质纤维素材料的酶水解受到纤维素酶吸附到木质纤维素底物和木质素上的显著影响。木质素的存在在木质纤维素水解和酶循环中起着重要作用。评估了三种纤维素酶制剂（Celluclast、Spezyme CP和MSUBC），以确定它们对来自蒸汽爆破的黑松（SELP）和乙醇（有机溶剂法）预处理的黑松（EPLP）的纤维素分解酶木质素（CEL）的吸附情况。基于朗缪尔常数，纤维素酶（Celluclast）对分离出的木质素（CEL-EPLP和CEL-SELP）的吸附亲和力略高于相应的EPLP和SELP底物。本研究还探讨了温度、离子强度和表面活性剂对纤维素酶吸附到分离出的木质素上所产生的影响。对酶吸附到分离出的木质素上的热力学分析（吉布斯自由能变化ΔG(0)约为 -30 kJ/mol）表明这种吸附是一个自发过程。添加表面活性剂（0.2% w/v）可使纤维素酶对CEL-SELP的吸附降低60%。比较了两种吸附等温线用于纤维素酶吸附到分离出的木质素上的情况。与弗伦德利希吸附等温线相比，朗缪尔吸附等温线对实验数据的拟合效果更好。
