Monday, May 5, 2008 - 4:00 PM
6-05
Thermophilic fungal CBH enzymes for hydrolysis of lignocellulosic materials
Matti Siika-aho1, Sanni Voutilainen1, Anu Koivula1, Jari Vehmaanperä2, and Liisa Viikari3. (1) Biotechnology, VTT Technical Research Centre of Finland, P.O. Box 1000, FIN-02044 VTT, Espoo, Finland, (2) ROAL Oy, P.O.Box 57, FIN-05200, Rajamäki, Finland, (3) University of Helsinki, P.O. Box 27, FIN-00014, Helsinki, Finland
Enzymatic hydrolysis is currently considered as the primary option to produce sugars from biomass for microbial fermentation to various chemicals, including ethanol. Use of thermostable cellulases could improve the overall efficiency of enzymatic hydrolysis of lignocellulosic materials, due to potentially higher specific activities and increased hydrolysis rates. Higher thermal activity can also provide flexibility in selection of process options. Even though a consortium of synergistic enzymes is required for efficient total hydrolysis, the key cellulases required are cellobiohydrolases. In present commercial cellulases, these comprise mainly of fungal family 7 enzymes. In order to find new improved cellulases and optimal enzyme mixtures, comparison of the key components is required, followed by evaluation of these enzymes in hydrolysis experiments using pre-treated substrates. In this work, thermostable Cel7A enzymes were studied in order to develop new superior enzyme products for lignocellulose hydrolysis.
The kinetic data of thermostable fungal Cel 7A enzymes were compared and their performance in hydrolysis of pre-treated lignocellulosic raw materials was analysed. The cellobiohydrolases were compared to CBHI (Cel7A) of T. reesei, which is one of the most thoroughly studied fungal cellobiohydrolases. Several thermostable CBH’s were purified, cloned and their enzymatic properties were characterized. Enzyme constructs containing only the catalytic core modules or the entire two-module proteins (composed of the catalytic and the cellulose-binding modules) were also studied. Interesting substrate-specific differences in the hydrolysis performance were detected. Pre-treated lignocellulosic raw materials were efficiently hydrolysed at elevated temperatures by these enzymes, when used in mixtures with other thermostable enzymes.
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See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)