Biomass Depolymerization programs
Microbiological and Biochemical Approaches to Overcome Biomass Recalcitrance - Completed
This program studied enzymatic and microbiological approaches for degradation of lignocellulose that would convert the energy-rich cellulose more efficiently to fuels. Gerlt's group obtained genome sequences for bacterial (Streptomycetes) species that degrade Miscanthus lignocellulose. With genome sequences and either an appropriate scaffold sequence from an organism that does not degrade lignocellulose or identification of oxidative enzymes that are produced/secreted in the presence of Miscanthus lignocellulose, they could identify islands of genes that encode enzymes involved in lignocellulose degradation. Characterization of these enzymes provided information to help (re)design pathways in genetically tractable organisms to facilitate lignocellulose degradation.
Gerlt’s group demonstrated that the SLAC (a copper-containing enzyme) is able to reconstruct ethanosolv lignin, producing higher molecular weight species. They have evidence that the net deconstruction of lignin requires interception of radical intermediates generated by the action of SLAC (and other oxidases/peroxidases). They also found that the catalytic properties of SLAC can be altered by mutating the binding site for the T1 copper, presumably by altering the redox potential of the copper.