Acetic acid-catalyzed hydrothermal pretreatment of corn stover for the production of bioethanol at high-solids content

• Published in: Bioprocess and biosystems engineering Vol. 39; no. 9; pp. 1415 - 1423
• Main Authors: Katsimpouras, Constantinos, Christakopoulos, Paul, Topakas, Evangelos
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-09-2016; Springer Nature B.V
• Subjects: Acetates - chemistry; Acetic acid; Biochemical Process Engineering; Biodiesel fuels; Biofuels; Biokemisk processteknik; Biotechnology; Catalysis; Chemistry; Chemistry and Materials Science; Corn; Distillation; Dry matter; Environmental Engineering/Biotechnology; Enzymes; Ethanol; Ethanol - metabolism; Fermentation; Food Science; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Lignocellulose; Liquefaction; Microscopy, Electron, Scanning; Original Paper; Stover; Viscosity; Zea mays - chemistry; Enzymatic liquefaction; Ethanol fermentation; Pretreatment; Response surface methodology; Corn stover
• ISSN: 1615-7591; 1615-7605; 1615-7605
• DOI: 10.1007/s00449-016-1618-5

Corn stover (CS) was hydrothermally pretreated using CH
3
COOH (0.3 %, v/v), and subsequently its ability to be utilized for conversion to ethanol at high-solids content was investigated. Pretreatment conditions were optimized employing a response surface methodology (RSM) with temperature and duration as independent variables. Pretreated CS underwent a liquefaction/saccharification step at a custom designed free-fall mixer at 50 °C for either 12 or 24 h using an enzyme loading of 9 mg/g dry matter (DM) at 24 % (w/w) DM. Simultaneous enzymatic saccharification and fermentation (SSF) of liquefacted corn stover resulted in high ethanol concentration (up to 36.8 g/L), with liquefaction duration having a negligible effect. The threshold of ethanol concentration of 4 % (w/w), which is required to reduce the cost of ethanol distillation, was surpassed by the addition of extra enzymes at the start up of SSF achieving this way ethanol titer of 41.5 g/L.