Catalytic Hydrogels from Bifunctional Enzymatic Building Blocks

Columbia University, New York NY

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5) This award by the Biomaterials program in the Division of Materials Research to Columbia University is study the use of molecular engineering to create novel bifunctional enzymes that can self-assemble into hydrogels and support an intra-gel metabolic pathway that can oxidize methanol through two steps to formic acid. Rationally designed alpha-helical appendages will be genetically fused to the horse liver alcohol dehydrogenase homodimer enzyme and to the human liver mitochondrial aldehyde dehydrogenase homotetramer enzyme. The effects of these mutations on the performance of the enzymes will be assessed, and then the enzymes will be combined to form mixed self-assembling hydrogels that will oxidize methanol to formic acid while concomitantly producing NADH from NAD+ a cofactor required for the reaction. This will be the first proof of principle of a self-assembling bioactive biomaterial that can support a simple intra-gel metabolic network. This material could be applied to an electrode and used as an anode in an enzymatic biofuel cell using methanol as a fuel source. Protein engineering has been used to improve globular proteins such as enzymes, and structural proteins such as the elastin-like peptides. This research project is designing and creating new proteins with both globular and structural domains to form bioactive biomaterials. Earlier studies by the researcher already modified proteins to self-assemble into enzymatic hydrogels, and in this proposal the investigators will create a new material that contains two active enzymes which can function together to form a simple metabolic pathway. The enzymes will be able to oxidize methanol first to formaldehyde and then the formaldehyde will be oxidized to formic acid. Each step will generate NADH which can be used in a power generating format such as an enzymatic biofuel cell. The creation of novel protein constructs with both useful enzymatic and materials properties is a new area in the field of protein engineering, and this approach will be very useful in the design and construction of new bioelectrocatalytic devices such as enzymatic biofuel cells and biosensors.