Characterization and optimization of carbohydrate-binding modules (CBMs) for biomass conversion

This project belongs to VISTA's previous research area Biotechnology

A major bottleneck in the process of converting biomass to useful products such as biofuels or biomaterials is the enzymatic conversion of biomass to soluble mono-components (i.e. sugar). Although progress is being made, the efficiency of the current enzyme preparations used by industry hamper the process of making this a cost-effective operation. The recent discovery of a new family of enzymes (polysaccharide oxidizes; CBM33 and GH61) that add a substantial boost to the current enzymes used in biomass conversion has spurred hope for designing hyper-effective enzyme preparations. The main objective of the current project is to obtain a more fundamental understanding of how this new family of enzymes (with focus on bacterial CBM33s) operates in order to enable maximization of the enzyme efficiencies on specific biomass substrates (i.e. deducing physo-chemical optimums for enzyme activity, co-factor dependencies etc.). Once a generally good understanding of the enzymatic properties are obtained, methods involving various protein engineering techniques will be used to improve/ optimize specific enzyme properties that are attractive from an industrial point of view.

Objectives:

Major objective: Development and characterization of family 33 carbohydrate-binding modules for more effective enzymatic conversion of lignocellulosic biomass.

 Sub-goals:

1. Finding, expressing and characterizing naturally occurring proteins that act synergistically with cellulases during enzymatic degradation of lignocellulose.
2. Identify or generate CBM33s that act synergistically with cellulases during enzymatic degradation of lignocellulose and improvement of these candidates by protein engineering and/or directed evolution.
3. In-depth characterization of promising natural or engineered CBM33s, and evaluation of their potential in industrial enzymatic conversion of lignocellulosic biomass.

Publications:

Forsberg, Z., Vaaje‐Kolstad, G., Westereng, B., Bunas, A.C., Stenstrom, Y., MacKenzie, A., Sorlie, M., Horn, S.J., Eijsink, V.G.H., 2011, Cleavage of cellulose by a CBM33 protein, Protein Science, 20 (9), 1479‐1483.

Vaaje-Kolstad, G., Westereng, B., Eijsink, V.G.H., Horn, S.J., Sorlie, M., Forsberg, Z. Methods of Degrading or Hydrolyzing a Polysaccharide; PCT/US2011/046838

Forsberg, Z., Røhr, A.K., Mekasha, S., Andersson, K.K., Eijsink, V.G.H., Vaaje-Kolstad, G., Sørlie, M., 2014, Comparative study of two chitin-active and two cellulose-active AA10-type lytic polysaccharide monooxygenases, Biochemistry, (10), 1647-1656.

Forsberg, Z., Mackenzie, A.K., Sørlie, M., Røhr, Å.K., Helland, R., Arvai, A.S., Vaaje-Kolstad, G., Eijsink, V.G.H., 2014, Structural and functional characterization of a conserved pair of bacterial cellulose-oxidizing lytic polysaccharide monooxygenases, Proc. Natl. Acad. Sci. USA, 111 (23), 8446-8451.