title: Consolidated bioprocessing (CBP) of AFEX™-pretreated corn stover for ethanol production using Clostridium phytofermentans at a high solids loading.
abstract: Consolidated bioprocessing (CBP) using Clostridium phytofermentans (ATCC 700394) on ammonia fiber expansion (AFEX™)-treated corn stover (AFEX™-CS) at a low solids loading showed promising results [Jin et al. (2011) Biotechnol Bioeng 108(6): 1290-1297]. However, industrial relevant process requires high solids loading. Therefore, we studied high solids loading CBP performance on AFEX™-CS. The factors potentially affecting the performance including solids loading, CBP products acetate and ethanol, and degradation products resulting from pretreatment were investigated. At 4% (w/w) glucan loading, C. phytofermentans performed well on AFEX™-CS with no nutrients supplementation and reached similar sugar conversions as a fermentation with nutrients supplementation. A glucan conversion of 48.9% and a xylan conversion of 77.9% were achieved after 264 h with 7.0 g/L ethanol and 8.8 g/L acetate produced. Relatively high concentrations of acetate produced at high solids loading was found to be the major factor limiting the CBP performance. Degradation products in AFEX™-CS helped enhance ethanol production.
authors.affiliation: Biomass Conversion Research Laboratory, Department of Chemical Engineering and Materials Science, Michigan State University, Lansing, Michigan 48910, USA. jinmingj@egr.msu.edu
authors.forename: Mingjie
authors.initials: M
authors.lastname: Jin
authors.forename: Christa
authors.initials: C
authors.lastname: Gunawan
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Balan
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Dale
mesh_terms: D000085:Acetates / Q000378:metabolism; D001709:Biotechnology / Q000379:methods*; D003013:Clostridium / Q000254:growth & development* / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005936:Glucans / Q000378:metabolism; D003313:Zea mays / Q000378:metabolism*
chemical_list: D000085:Acetates; D005936:Glucans; D000431:Ethanol