title: A fractal-like kinetic equation to investigate temperature effect on cellulose hydrolysis by free and immobilized cellulase.
abstract: According to fractal-like theory in the heterogeneous system, a cellulase-catalyzed kinetic equation that contained two parameters (rate constant k and fractal dimension h) was deduced. The equation described directly the mathematical relationship between reducing sugar concentration and hydrolytic time, and accurately fitted the experimental data of free/immobilized cellulase at 37, 40, 44, 47, and 50 °C (R(2)>0.99). The fitted h value is estimated as a constant (0.6148) in these tested temperatures. The fitted k value increased with temperature increase, and the relationship agreed with Arrhenius equation (R(2)>0.98). The fractal-like equation could predict accurately the experimental data at low temperature 34 °C for free/immobilized cellulase and high temperature 53 °C for immobilized cellulase, but the prediction at 53 °C for free cellulase was not accurate enough due to its lower stability than immobilized cellulase. The application of fractal-like theory in cellulase kinetics is successful.
authors.affiliation: Key Laboratory of Renewable Energy and Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, No. 2, Nengyuan Road, Wushan, Tianhe, Guangzhou 510640, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jing-Liang
authors.initials: JL
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Qi
authors.forename: Zhen-Hong
authors.initials: ZH
authors.lastname: Yuan
authors.forename: Xin-Shu
authors.initials: XS
authors.lastname: Zhuang
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Min-Chao
authors.initials: MC
authors.lastname: He
mesh_terms: D000468:Alkalies / Q000737:chemistry; D002241:Carbohydrates / Q000032:analysis; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000378:metabolism; D017709:Fractals; D006868:Hydrolysis; D007700:Kinetics; D008954:Models, Biological; D010084:Oxidation-Reduction; D012044:Regression Analysis; D013696:Temperature
chemical_list: D000468:Alkalies; D002241:Carbohydrates; D004800:Enzymes, Immobilized; D002482:Cellulose; D002480:Cellulase