Efficient use of brewer's spent grain hydrolysates in ABE fermentation by Clostridium beijerinkii. Effect of high solid loads in the enzymatic hydrolysis

• Published in: Journal of chemical technology and biotechnology (1986) Vol. 95; no. 9; pp. 2393 - 2402
• Main Authors: Plaza, Pedro E, Coca, Mónica, Lucas, Susana, Fernández‐Delgado, Marina, López‐Linares, Juan C, García‐Cubero, María Teresa
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.09.2020; Wiley Subscription Services, Inc
• Subjects: Acetone; Activated carbon; brewer's spent grain; high solid loads; enzymatic hydrolysis; detoxification; ABE fermentation; Butanol; Detoxification; Ethanol; Fermentation; Hydrolysates; Hydrolysis; Phenolic compounds; Phenols; Pretreatment; Sugar
• ISSN: 0268-2575; 1097-4660
• DOI: 10.1002/jctb.6421

BACKGROUND Brewer's spent grain (BSG) has been employed to investigate the use of hemicellulosic and cellulosic sugars in Acetone‐Butanol‐Ethanol (ABE) fermentation. A dilute‐acid pretreatment was conducted, followed by enzymatic hydrolysis at different solid loads (10–15–20% DM) and ABE fermentation by Clostridium beijerinckii DSM 6422. Operation at solid loadings higher than 15% DM (60.1 g L−1 of total sugars, 1.03 g phenolic/L) makes the development of a detoxification step necessary. RESULTS The higher butanol and ABE concentrations for the pretreatment liquor were obtained when activated carbon was used as the detoxification agent (11.5 ± 0.1 g L−1 butanol, 16.2 ± 0.2 g L−1 ABE, 95.1% sugar uptake), whereas the sequential activated carbon and overliming detoxification strategy was the most effective for 15% DM enzymatic hydrolysates (11.6 ± 0.2 g L−1 butanol, 18.3 ± 0.3 g L−1 ABE, 89.6% sugar uptake). CONCLUSION The overall yield, taking into account the pretreatment liquor and enzymatic hydrolysate, was 99.8 g butanol/kg BSG and 146.5 g ABE/kg BSG, improving the results without detoxification by more than 40%. © 2020 Society of Chemical Industry