Pedro Alves Martins

Project title: Exploring Diversity and binding of Glucuronoyl Esterases (EDGE)

Host Institution: Technical University of Denmark (DTU)

Host Supervisor: Dr. Jane W. Agger

Co-host Institution: École Polytechnique Fédérale de Lausanne (EPFL)

Co-host Supervisor: Dr. Jeremy Luterbacher

Summary project: The growing environmental concern to reduce fossil fuel derived energy and materials disclose the need for sustainable alternatives. In a bio-based economy context, enzyme technology can be applied to supply consumer and societal needs as sustainable alternative technologies to harness lignocellulosic biomass and efficiently achieve low environmental impacts along economic benefits.
Lignocellulose is recalcitrant by nature, and this recalcitrance represents one of the biggest challenges for efficient use. At the same time, new trends move towards increasing the use of the native properties of the polymeric structures of lignocellulose, rather than aiming for complete depolymerization. In particular, lignin receives a tremendous amount of attention due to its potentials as the new and green raw material. Altogether, this sets new and challenging needs for developing new process schemes that allow selective fractionation of polymers and in this context, precise enzyme catalysis is of paramount importance. With EDGE, I want to make fundamentally new breakthroughs in the understanding of how glucuronoyl esterases (GEs) catalyse the hydrolysis of ester linkages between xylan and lignin, and thereby assist in the exact separation between polymers and extraction of lignin from the cell wall matrix. Despite previous research efforts, fundamental questions in relation to GEs remain open, and in EDGE I am addressing the questions: 1) How do GEs interact with lignocellulose and lignin? 2) How do the Carbohydrate-Binding Modules (CBM) determine GE’s substrate affinity and binding patterns? 3) How does the enzymatic diversity affect the substrate preferences of the enzymes? To answer these questions, I am exploring the diversity of GEs by selecting enzyme candidates from fungal and bacterial origin and investigating their specific activity, substrate preferences, and synergistic action with other carbohydrate-active enzymes in lignocellulose hydrolysis, at the host institution. With the co-host, I will study the molecular binding interactions between GEs and biomass mediated by CBMs (either naturally occurring or engineered constructs) using a novel approach based on solid-state NMR spectroscopy and develop new generic methodology that is directly transferable to other lignocellulose-related enzymes.
The expected outcome of EDGE is to understand the diversity among GEs and how CBMs influence their substrate specificity. By doing that, EDGE will provide new insights into these enzymes’ function-related characteristics to understand how they can be explored for future industrial applications in biomass deconstruction and advancement of biorefinery-based applications.