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

Pia-Maria Bondesson, Mats Galbe

Research output: Contribution to journalArticlepeer-review

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.
Original languageEnglish
Article number222
JournalBiotechnology for Biofuels
Volume9
Issue number1
DOIs
Publication statusPublished - 2016 Oct 18

Subject classification (UKÄ)

  • Bioprocess Technology

Free keywords

  • Acetic acid
  • Wheat straw
  • Steam pretreatment
  • Ethanol
  • Simultaneous saccharification and co-fermentation (SSCF)
  • Fed-batch
  • Saccharomyces cerevisiae

Fingerprint

Dive into the research topics of 'Process design of SSCF for ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw'. Together they form a unique fingerprint.

Cite this