Renewable Energy, Vol.171, 971-980, 2021
Aqueous pretreatment of triticale straw for integrated production of hemicellulosic methane and cellulosic butanol
Despite its advantages, lignocellulosic butanol cannot become a real alternative without processes for obtaining credits from non-cellulosic fraction of lignocellulose. In this study, the process of "cellulosic butanol" was integrated with "hemicellulosic methane" process, i.e., anaerobic digestion (AD), for higher energy return on investment (EROI). Aqueous pretreatment was evaluated as a connecting chain between the processes. The alkaline (1% NaOH), acidic (1% H2SO4), and neutral (autohydrolysis) pretreatments were utilized at 140, 160, and 180 degrees C for bioenergy recovery from triticale straw. Enzymatic hydrolysis of the straw pretreated by alkaline (180 degrees C), dilute acid (140 degrees C), and autohydrolysis (180 degrees C) and fermentation of the hydrolysates by Clostridium acetobutylicum led to 13.6, 8.5, and 10.2 g/L acetone-butanol-ethanol (ABE), respectively. AD of the liquors remained after pretreatment by alkaline, dilute acid, and autohydrolysis led to 83-121, 240-247, and 380-430 mL/g VSS methane leading to more than 60% increase in EROI. (C) 2021 Elsevier Ltd. All rights reserved.
Keywords:ABE fermentation;Triticale straw;Biobutanol;Clostridium acetobutylicum;Methane;Anaerobic digestion