Thursday, May 2, 2013: 10:55 AM
Pavilion, Plaza Level
Jian Shi1, John M. Gladden
1, Pavan Kambam
2, Lucas Sandavol
2, Sonny Zhang
3, Steve W. Singer
4, Blake A. Simmons
1 and Seema Singh
1, (1)Biological and Materials Science Center, Sandia National Laboratories/Joint BioEnergy Institute, Emeryville, CA, (2)The Advanced Biofuels Process Demonstration Unit (ABPDU), Lawrence Berkeley National Laboratory, Emeryville, CA, (3)Deconstruction, Joint BioEnergy Institute, Emeryville, CA, (4)Joint BioEnergy Institute / Lawrence Berkeley National Laboratory, Berkeley, CA
Certain ionic liquid (ILs) are highly effective at reducing the recalcitrance of lignocellulosic biomass to enzymatic degradation. Commercial enzyme cocktails, however, are inhibited by low concentrations of the ILs used during pretreatment. As a result, excessive amounts of water are currently required to remove the ILs from biomass after pretreatment. The associated IL recycling and waste disposal costs of this process poses significant challenges for the commercial scale-up of IL pretreatment technology.
For the first time, we have demonstrated a "one-pot", wash-free, process for consolidated IL pretreatment and saccharification of switchgrass. After treating the switchgrass with the IL 1-ethyl-3-methylimidazolium acetate [C2mim][OAc], the mixture of biomass and IL was diluted with water to a final concentration of 10 and 20%. The pretreatment slurry was directly hydrolyzed using a thermostable IL tolerant enzyme cocktail developed at JBEI, called JTherm. This consolidated process liberated 81.2% glucose and 87.4% xylose (monomers and oligomers) at 72h at 70 оC with an enzyme loading of 5 mg/g of biomass. Glucose and xylose were then selectively separated by liquid-liquid extraction with over 90% efficiency and generated a hydrolysate suitable for fermentation.
This consolidated process eliminated extensive water washing as a unit operation and could drastically simplify the downstream sugar/lignin recovery and IL recycle, thereby significantly improving the overall process economics of the IL pretreatment technology.
