Tailoring lignocellulosic biomass for chemical conversion technologies

Biomass has one-third the energy density of crude oil and lacks petroleum’s versatility as a feedstock for fuels and chemicals. Chemical catalysis and fast pyrolysis can overcome these limitations by transforming the main components of biomass (cellulose, xylan, and lignin) from grasses and trees directly to liquid hydrocarbons and aromatic co-products. Our data show that, regardless of conversion process, biomass structural complexity at molecular, nanoscale, and mesoscale levels impacts the yields and selectivities of desired reaction products from catalytic and pyrolytic transformations. Therefore, we have modified the composition and architecture of cell wall components to optimize post-conversion product yields without compromising pre-conversion biomass yields. Our strategies to deliver metal catalysts throughout the cell wall structure and create functionalized sites ready for catalytic transformations may dramatically increase the effective surface area for catalysis of cellulose and xylan. We have developed control science methods to chemically induce lignification, modify its monolignol composition, and quantify its extent. Genetic redesign of the lignin network simplifies its architecture to enable facile catalytic disassembly and conversion of aromatics. Prior disassembly of about half of the lignin from intact woody biomass using a Zn2+/Pd/C catalytic system dramatically improves subsequent saccharification yield and allows a re-visioning of the cellulosic biorefinery concept.

Supported by C3Bio, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Basic Energy Sciences.