title: Toward high solids loading process for lignocellulosic biofuel production at a low cost.
abstract: High solids loadings (>18 wt%) in enzymatic hydrolysis and fermentation are desired for lignocellulosic biofuel production at a high titer and low cost. However, sugar conversion and ethanol yield decrease with increasing solids loading. The factor(s) limiting sugar conversion at high solids loading is not clearly understood. In the present study, we investigated the effect of solids loading on simultaneous saccharification and co-fermentation (SSCF) of AFEX™ (ammonia fiber expansion) pretreated corn stover for ethanol production using a xylose fermenting strain Saccharomyces cerevisiae 424A(LNH-ST). Decreased sugar conversion and ethanol yield with increasing solids loading were also observed. End-product (ethanol) was proven to be the major cause of this issue and increased degradation products with increasing solids loading was also a cause. For the first time, we show that with in situ removal of end-product by performing SSCF aerobically, sugar conversion stopped decreasing with increasing solids loading and monomeric sugar conversion reached as high as 93% at a high solids loading of 24.9 wt%. Techno-economic analysis was employed to explore the economic possibilities of cellulosic ethanol production at high solids loadings. The results suggest that low-cost in situ removal of ethanol during SSCF would significantly improve the economics of high solids loading processes. Biotechnol. Bioeng. 2017;114: 980-989. © 2016 Wiley Periodicals, Inc.
authors.affiliation: School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.|Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, DOE Great Lakes Bioenergy Research Center, Michigan State University, Lansing, Michigan.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Jin
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, DOE Great Lakes Bioenergy Research Center, Michigan State University, Lansing, Michigan.
authors.forename: Cory
authors.initials: C
authors.lastname: Sarks
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, DOE Great Lakes Bioenergy Research Center, Michigan State University, Lansing, Michigan.
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Bals
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, DOE Great Lakes Bioenergy Research Center, Michigan State University, Lansing, Michigan.
authors.forename: Nick
authors.initials: N
authors.lastname: Posawatz
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, DOE Great Lakes Bioenergy Research Center, Michigan State University, Lansing, Michigan.
authors.forename: Christa
authors.initials: C
authors.lastname: Gunawan
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, DOE Great Lakes Bioenergy Research Center, Michigan State University, Lansing, Michigan.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Dale
authors.affiliation: Biomass Conversion Research Laboratory (BCRL), Department of Chemical Engineering and Materials Science, DOE Great Lakes Bioenergy Research Center, Michigan State University, Lansing, Michigan.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Balan
mesh_terms: D000641:Ammonia / Q000378:metabolism; D056804:Biofuels / Q000032:analysis / Q000191:economics; D019149:Bioreactors / Q000191:economics / Q000382:microbiology; D000431:Ethanol / Q000032:analysis / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014994:Xylose / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry
chemical_list: D056804:Biofuels; C036909:lignocellulose; D000431:Ethanol; D000641:Ammonia; D008031:Lignin; D014994:Xylose; D005947:Glucose
keywords: AFEX; AFEX is a trademark of MBI; Michigan; SSCF; corn stover; enzymatic hydrolysis; ethanol; lansing; solids loading