Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
681740 | Bioresource Technology | 2011 | 8 Pages |
The production of fermentable substrates from barley straw under various process conditions was studied. Pretreatment included chemical pretreatment with dilute-acid followed by enzymatic hydrolysis; the pretreatment conditions were expressed in a combined severity factor, CS, which ranged in the present study from −1.6 to 1.1. Considering the production of fermentable sugars and the release of inhibitory compounds, the optimal pretreatment conditions were 170 °C, 0% sulfuric acid and 60 min, corresponding to CS −0.4. Under these conditions, 21.4 g glucose/L, 8.5 g xylose/L, and 0.5 g arabinose/L were produced, while 0.1 g HMF/L, 0.4 g furfural/L, 0.0 g levulinic acid/L, 0.0 g formic acid/L, and 2.1 g acetic acid/L were released. The ratio of Σsugars/Σinhibitors proved to be a good tool for evaluating the suitability of a hydrolysate for fermentation purposes.
► We studied dilute-acid pretreatment of barley straw at low combined severity (−1.6 to 1.1). ► We monitored the production of fermentable sugars and the release of five inhibitory compounds. ► We optimized the pretreatment conditions at 170 °C, 0% sulfuric acid and 60 min. ► We used the ratio of Σsugars/Σinhibitors to evaluate the suitability of barley straw hydrolysates for fermentation purposes. ► We discussed the effect of the concentrations of the inhibitors on ethanol and hydrogen fermentability.