Applied Biochemistry and Biotechnology

, Volume 126, Issue 1, pp 49–59

Enzymatic kinetic of cellulose hydrolysis

Inhibition by ethanol and cellobiose
Original Articles

DOI: 10.1007/s12010-005-0005-5

Cite this article as:
Bezerra, R.M.F. & Dias, A.A. Appl Biochem Biotechnol (2005) 126: 49. doi:10.1007/s12010-005-0005-5


The ethanol effect on the Trichoderma reesei cellulases was studied to quantify and clarify this inhibition type. To determine inhibition parameters of crude cellulase and purified exoglucanase Cel7A, integrated Michaelis-Menten equations were used assuming the presence of two inhibitors: cellobiose as the reaction product and ethanol as a possible bioproduct of cellulose fermentation.

It was found that hydrolysis of cellulose by crude enzyme follows a model that considers noncompetitive inhibition by ethanol, whereas Cel7A is very slightly competitively inhibited. Crude cellulase is much more inhibited (Kiul=Kicl=151.9 mM) than exoglucanase Cel7A (Kicl=1.6 × 1015 mM). Also, calculated inhibition constants showed that cellobiose inhibition is more potent than ethanol inhibition both for the crude enzyme as well as exoglucanase Cel7A.

Index Entries

Cellulase kineticsethanol inhibitionexoglucanase Cel7Aintegrated Michaelis-Menten equationskinetic with two inhibitors

Copyright information

© Humana Press Inc 2005

Authors and Affiliations

  1. 1.CETAV-Departamento de Engenharia Biológica e AmbientalUniversidade de Trás-os-Montes e Alto Douro, Apartado 1013Vila RealPortugal