Study of an extremophilic ß-endoglucanase

• Antragsteller: Privatdozent Dr. Georg Lipps
• Fachliche Zuordnung: Stoffwechselphysiologie, Biochemie und Genetik der Mikroorganismen
• Förderung: Förderung von 2006 bis 2011
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 33995745

The ß-endoglucanase SSO1949 from Sulfolobus solfataricus is an extremophilic enzyme with outstanding properties. This enzyme has its highest activity at pH 1.8 and 80 °C, and it is more stable under acidic conditions than at neutrality. Such a combination of extremophilic properties has not been reported for any other ß-endoglucanase. For the production of fermentable sugars from cellulosic biomass, an acidophilic ß-endoglucanase could be of great advantage since the raw biomass must be pretreated which is most commonly done with acids. In this application we want to investigate the biochemical and structural details which form the basis of the extremely low pH optimum of SSO1949 and we intend to improve the catalytic efficiency of SSO1949 against crystalline or acid-swollen cellulose. We will construct mutants with amino acid changes at the active site and study the activity of the mutants. To rationalize the effects of amino acid changes, a crystal structure of SSO1949 would be valuable and is also part of this project. Moreover we will study the stability of SSO1949 under acidic conditions with unfolding experiments in order to understand the high stability of the enzyme at low pH. Furthermore we will construct fusions of the catalytic domain of SSO1949 with carbohydrate binding modules in order to improve the catalytic efficiency against cellulose. Finally we will randomly generate mutant enzyme and screen them for increased enzymatic activity. The application combines basic research in enzymology with applied research for the use of heat- and acid-stable ß-endoglucanase for cellulose depolymerisation.

• DFG-Verfahren: Sachbeihilfen
• Internationaler Bezug: Frankreich
• Beteiligte Personen: Dr. Hugues Driguez; Professor Dr. Richard Haser