Cellulase Engineering for Renewable Fuels and Chemical
Current Personnel: Kevin Boulware, Martina Carbone, Mary Farrow, Pete Heinzelman, Florence Mingardon, Andrea Rentmeister, Philip Romero, Chris Snow, Indira Wu

Meeting the world’s rapidly growing energy needs while protecting Earth’s increasingly threatened climate balance is one of the greatest challenges we face as a society. Creating fuel from cellulosic biomass has the potential to offset a significant amount of our energy needs, but a major bottleneck in this process is conversion of cellulose to fermentable sugars. There remain significant gaps in our fundamental knowledge of how complex cellulosic materials are degraded. The Arnold lab is using its long experience in enzyme evolution and engineering to construct novel cellulases for extracting fuels and chemicals from biomass. This structure representation is of a highly thermostable recombinant of related cellulases from three different fungi: H. jecorina, H. insolens, and C. thermophilum. This ‘chimeric’ enzyme was created by structure-guided SCHEMA recombination and total gene synthesis. This enzyme is more stable and degrades more cellulose at high temperatures than any of its parent enzymes. (Heinzelman et al., Proceedings of National Academy of Sciences, 2009).
   

We are using structure-guided recombination (SCHEMA) to create whole families of thermostable cellulases, starting from highly active parent enzymes that are not necessarily thermostable. The goal is to make enzymes that function at much higher temperatures, where cellulose accessibility and degradation are strongly enhanced. We are also using methods of directed evolution—accumulation of beneficial mutations over multiple rounds of random mutagenesis and high throughput screening—to generate a variety of improved cellulases.