The effect of mixed agricultural feedstocks on steam pretreatment, enzymatic hydrolysis, and cofermentation in the lignocellulose-to-ethanol process

Research output: Contribution to journalArticle

Abstract

Second-generation fuel ethanol is typically researched using one type of raw material as feedstock. However, the variability in the supply and quality of biomass calls for an expansion of the feedstock base to ensure sufficient supply for commercial-scale production. By expanding the feedstock base and using mixtures in the conversion process, the biomass supply can be improved and associated economic risks can be hedged. However, the heterogeneity of feedstock mixtures requires conversion processes that can accommodate mixtures with no or minimal reduction in conversion efficiency compared to processing single feedstocks. In this study, the effects of using mixtures of wheat straw and corn stover on conversion efficiency and ethanol yield were investigated. The feedstocks and mixtures thereof were pretreated with dilute acid–catalysed steam pretreatment, and saccharified and cofermented using different simultaneous saccharification and cofermentation (SSCF) configurations, employing commercial cellulolytic enzymes and a xylose-fermenting strain of Saccharomyces cerevisiae. Process ethanol yields, based on total glucose and xylose in the raw material, were maximised by SSCF configurations that emphasise the saccharification efficiency over cofermentation efficiency. Ethanol concentrations exceeding 50 g L−1 and process ethanol yields of 74–78% of the theoretical maximum were achieved across the range of feedstocks and feedstock mixtures studied. The narrow range of the ethanol yields suggests that wheat straw and corn stover can be used interchangeably and mixed in the proposed lignocellulose-to-ethanol process without significant negative effects on conversion efficiency and process economics.

Details

Authors
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Process Engineering
  • Renewable Bioenergy Research

Keywords

  • Cofermentation, Lignocellulose, Mixed feedstocks, Prefermentation, Prehydrolysis, Saccharomyces cerevisiae, SSCF, Xylose fermentation
Original languageEnglish
JournalBiomass Conversion and Biorefinery
Publication statusE-pub ahead of print - 2019
Publication categoryResearch
Peer-reviewedYes