Enhanced biobutanol production from corncob <i>via</i> dilute trifluoroacetic acid compared with dilute sulfuric acid pretreatment

Abstract Efficient hydrolysis of hemicellulose to fermentable carbohydrates is crucial for producing butanol from lignocellulose. This study investigates hydrothermal pretreatment catalyzed by dilute trifluoroacetic acid (DTFA) to enhance the hydrolysis of hemicellulose in corncob. DTFA pretreatment generated a fermentable hemicellulose hydrolysate containing 75–80% xylan as xylose and a glucan‐rich solid. Pretreatment at 150 °C with 0.05 M trifluoroacetic acid released 80% xylan, yielding 23 g L −1 xylose and 13.8 g L −1 other sugars. Enzymatic hydrolysis of the 65.5% glucan solid yielded a cellulosic hydrolysate with 26 g L −1 glucose. DTFA pretreatment improved hydrolysis efficiency by 243% over untreated corncob and 62% over dilute sulfuric acid pretreatment. Acetone–butanol–ethanol (ABE) fermentation of the hydrolysates by Clostridium acetobutylicum produced 7.8–7.9 g L −1 ABE, utilizing 97% glucan and 75% xylan. The process was assessed based on the concentration of inhibitors and fermentable sugars. Dilute trifluoroacetic acid pretreatment yields 187 g of ABE per kg of corncob, compared with 42 g for DSA.