High-Efficiency Conversion of Ionic Liquid-Pretreated Woody Biomass to Ethanol at the Pilot Scale
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Advanced Biofuels and Bioproducts Process Demonstration Unit, Emeryville, CA (United States)
- Sandia National Lab. (SNL-CA), Livermore, CA (United States); Joint BioEnergy Institute, Emeryville, CA (United States)
- National Corn to Ethanol Research Center, Edwardsville, IL (United States); Southern Illinois Univ., Edwardsville, IL (United States)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Institute, Emeryville, CA (United States)
We report that with a diverse and widely distributed global resource base, woody biomass is a compelling organic feedstock for conversion to renewable liquid fuels. In California, woody biomass comprises the largest fraction of underutilized biomass available for biofuel production, but conversion to fuels is challenged both by recalcitrance to deconstruction and by toxicity toward downstream saccharification and fermentation due to organic acids and phenolic compounds generated during pretreatment. In this study, we optimize pretreatment and scale-up of an integrated one-pot process for deconstruction of California woody biomass using the ionic liquid (IL) cholinium lysinate [Ch][Lys] as a pretreatment solvent. By evaluating the impact of solid loading, solid removal, yeast acclimatization, fermentation temperature, fermentation pH, and nutrient supplementation on final ethanol yields and titers, we achieve nearly full conversion of both glucose and xylose to ethanol with commercial C5-utilizing Saccharomyces cerevisiae. We then demonstrate process scalability in 680 L pilot-scale fermentation, achieving >80% deconstruction efficiency, >90% fermentation efficiency, 27.7 g/L ethanol titer, and >80% ethanol distillation efficiency from the IL-containing hydrolysate post fermentation. This fully integrated process requires no intermediate separations and no intermediate detoxification of the hydrolysate. Using an integrated biorefinery model, current performance results in a minimum ethanol selling price of $$\$$$$8.8/gge. Reducing enzyme loading along with other minor process improvements can reduce the ethanol selling price to $$\$$$$3/gge. This study is the largest scale demonstration of IL pretreatment and biofuel conversion known to date, and the overall biomass-to-ethanol efficiencies are the highest reported to date for any IL-based biomass-to-biofuel conversion.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER); California Energy Commission
- Grant/Contract Number:
- AC02-05CH11231; GFO-17-902
- OSTI ID:
- 1844930
- Journal Information:
- ACS Sustainable Chemistry & Engineering, Vol. 9, Issue 11; ISSN 2168-0485
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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