title: Temperature sensitivity of cellulase adsorption on lignin and its impact on enzymatic hydrolysis of lignocellulosic biomass.
abstract: Unproductive enzyme adsorption is an important factor in addition to steric hindrance of lignin that limits the enzymatic hydrolysis of lignocellulosic biomass. While both are important factors, enzymatic hydrolysis of pretreated biomass is most likely conducted in the presence of certain amount of lignin residues that may not necessarily present accessibility hindrance, but can competitively absorb the enzyme. This paper presents a study with purified lignin samples to elucidate the role of unproductive enzyme adsorption. It appeared that lignin adsorbed cellulase quickly at 4 °C with adsorption equilibrium reached within 1h, similar to that observed for crystalline cellulose. Increasing temperature to 50 °C (typical hydrolytic reaction condition) facilitated the rate of cellulase adsorption on cellulose with a peak of adsorption reached at 0.25 h; however, adsorption on lignin was surprisingly slower and took over 12h to reach equilibrium, which was accompanied with a 10-fold increase in adsorption capacity. Despite the high adsorption capacity of lignin (which is comparable to that of cellulose) at 50 °C, the presence of added lignin imposed only minimal impact on the enzyme apparent activity, most likely due to the slow adsorption kinetics of lignin.
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors: Yingfu
authors: Y
authors: Zheng
authors: Songping
authors: S
authors: Zhang
authors: Shida
authors: S
authors: Miao
authors: Zhiguo
authors: Z
authors: Su
authors: Ping
authors: P
authors: Wang
mesh_terms: D000327:Adsorption; D018533:Biomass; D002480:Cellulase / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: C036909:lignocellulose; D008031:Lignin; D002480:Cellulase