Process design of SSCF for ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw

Research output: Contribution to journalArticle

Abstract

Background
Pretreatment is an important step in the production of ethanol from lignocellulosic material. Using acetic acid together with steam pretreatment allows the positive effects of an acid catalyst to be retained, while avoiding the negative environmental effects associated with sulphuric acid. Acetic acid is also formed during the pretreatment and hydrolysis of hemicellulose, and is a known inhibitor that may impair fermentation at high concentrations. The purpose of this study was to improve ethanol production from glucose and xylose in steam-pretreated, acetic-acid-impregnated wheat straw by process design of simultaneous saccharification and co-fermentation (SSCF), using a genetically modified pentose fermenting yeast strain Saccharomyces cerevisiae.

Results
Ethanol was produced from glucose and xylose using both the liquid fraction and the whole slurry from pretreated materials. The highest ethanol concentration achieved was 37.5 g/L, corresponding to an overall ethanol yield of 0.32 g/g based on the glucose and xylose available in the pretreated material. To obtain this concentration, a slurry with a water-insoluble solids (WIS) content of 11.7 % was used, using a fed-batch SSCF strategy. A higher overall ethanol yield (0.36 g/g) was obtained at 10 % WIS.

Conclusions
Ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw through SSCF with a pentose fermenting S. cerevisiae strain was successfully demonstrated. However, the ethanol concentration was too low and the residence time too long to be suitable for large-scale applications. It is hoped that further process design focusing on the enzymatic conversion of cellulose to glucose will allow the combination of acetic acid pretreatment and co-fermentation of glucose and xylose.

Details

Authors
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Bioprocess Technology

Keywords

  • Acetic acid , Wheat straw , Steam pretreatment , Ethanol , Simultaneous saccharification and co-fermentation (SSCF) , Fed-batch , Saccharomyces cerevisiae
Original languageEnglish
Article number222
JournalBiotechnology for Biofuels
Volume9
Issue number1
Publication statusPublished - 2016 Oct 18
Publication categoryResearch
Peer-reviewedYes

Related research output

Pia-Maria Bondesson, 2016 Oct 19, Lund, Sweden: Chemical Engineering, Lund University. 159 p.

Research output: ThesisDoctoral Thesis (compilation)

View all (1)