Abstract
A pilot plant for hydrothermal treatment of wheat straw was compared in reactor systems of two steps (first, 80°C; second, 190–205°C) and of three steps (first, 80°C; second, 170–180°C; third, 195°C). Fermentation (SSF) with Sacharomyces cerevisiae of the pretreated fibers and hydrolysate from the two-step system gave higher ethanol yield (64–75%) than that obtained from the three-step system (61–65%), due to higher enzymatic cellulose convertibility. At the optimal conditions (two steps, 195°C for 6 min), 69% of available C6-sugar could be fermented into ethanol with a high hemicellulose recovery (65%). The concentration of furfural obtained during the pretreatment process increased versus temperature from 50 mg/l at 190°C to 1,200 mg/l at 205°C as a result of xylose degradation. S. cerevisiae detoxified the hydrolysates by degradation of several toxic compounds such as 90–99% furfural and 80–100% phenolic aldehydes, which extended the lag phase to 5 h. Acetic acid concentration increased by 0.2–1 g/l during enzymatic hydrolysis and 0–3.4 g/l during fermentation due to hydrolysis of acetyl groups and minor xylose degradation. Formic acid concentration increased by 0.5–1.5 g/l probably due to degradation of furfural. Phenolic aldehydes were oxidized to the corresponding acids during fermentation reducing the inhibition level.
Similar content being viewed by others
References
Almeida JRM, Modig T, Petersson A, Hähn-Hägerdal B, Lidén G, Gorwa-Grauslund MF (2007) Increased tolerance and conversion of inhibitors in lignocellulosic hydrolysates by Saccharomyces cerevisiae. J Chem Technol Biotechnol 82:340–349
Bjerre AB, Sørensen E (1992) Thermal decomposition of dilute aqueous formic acid solutions. Ind Eng Chem Res 31:1574–1577
Clark TA, Mackie KL (1984) Fermentation inhibitors in wood hydrolysates derived from the soft wood Pinus radiata. J Chem Tech Biotechnol 34B:101–110
Delgenes JP, Moletta R, Navarro JM (1996) Effects of lignocellulose degradation products on ethanol fermentations of glucose and xylose by Saccharomyces cerevisiae, Zymomonas mobilis, Pichia stipitis, and Candida shehatae. Enzyme Microb Tech 19:220–225
Dunlop AP (1948) Furfural formation and behavior. Ind Eng Chem 40:204–209
Fengel D, Wegener G (1989) In: Wood: chemistry, ultrastructure, reactions. Walter de Gruyter, Berlin, p 613
Foussard J, Debellefontaine H, Besomes-Vaihle J (1989) Efficient elimination of organic liquid wastes: wet oxidation. Environ Eng 115:367–385
Kabel MA, Bos G, Zeevalking J, Voragen AGJ, Schols HA (2007) Effect of pretreatment severity on xylan solubility and enzymatic breakdown of the remaining cellulose from wheat straw. Bioresour Technol 98:2034–2042
Klinke HB, Thomsen AB, Ahring BK (2001) Potential inhibitors from wet oxidation of wheat straw and their effect on growth and ethanol production by Thermoanaerobacter mathranii. Appl Microbiol Biotechnol 57:631–638
Klinke HB, Ahring BK, Schmidt AS, Thomsen AB (2002) Characterization of degradation products from alkaline wet oxidation of wheat straw. Bioresour Technol 82:15–26
Klinke HB, Thomsen AB, Ahring BK (2004) Inhibition of ethanol-producing yeast and bacteria by degradation products produced during pre-treatment of biomass. Appl Microbiol Biotechnol 66:10–26
Larsson S, Palmqvist E, Hähn-Hägerdal B, Tengborg C, Stenberg K, Zacchi G, Nilvebrant NO (1999) The generation of fermentation inhibitors during dilute acid hydrolysis of softwood. Enzyme Micob Tech 24:151–159
Mishra VS, Mahajani VV, Joshi JB (1995) Wet air oxidation. Ind Eng Chem Res 34:2–48
Palmqvist E, Hähn-Hägerdal B (2000) Fermentation of lignocellulosic hydrolysates. II: inhibitors and mechanisms of inhibition. Bioresour Technol 74:25–33
Palmqvist E, Grage H, Meinander NQ, Hähn-Hägerdal B (1999) Main and interaction effects of acetic acid, furfural, and p-hydroxybenzoic acid on growth and ethanol productivity of yeasts. Biotechnol Bioeng 63:46–55
Puls J, Schuseil J (1993) Chemistry of hemicelluloses: Relationship between hemicellulose structure and enzymes required for hydrolysis, In: Coughlan MP, Hazlewood GP (eds) Hemicellulose and hemicellulases. Portland Press Research Monograph, pp 1–27
Rudolf A, Baudel H, Zacchi G, Hähn-Hägerdal B, Lidén G (2008) Simultaneous saccharification and fermentation of steam-pretreated bagasse using Saccharomyces cerevisiae TMB3400 and Pichia stipitis CBS6054. Biotechnol Bioeng 99:783–790
Sierra-Alvarez R, Lettinga G (1991) The methanogenic toxicity of wastewater lignins and lignin related compounds. J Chem Tech Biotechnol 50:443–455
Söderström J, Galbe M, Zacchi G (2004) Effect of washing on yield in one- and two-step steam pretreatment of softwood for production of ethanol. Biotechnol Prog 20:744–749
Taherzadeh MJ, Niklasson C, Lidén G (1997) Acetic acid—friend or foe in anaerobic batch conversion of glucose to ethanol by Saccharomyces cerevisiae. Chem Eng Sci 52:2653–2659
Taherzadeh MJ, Gustafsson L, Niklasson C, Lidén G (2000) Physiological effects of 5-hydroxymethylfurfural on Saccharomyces cerevisiae. Appl Microbiol Biotechnol 53:701–708
Thomsen AB (1998) Degradation of quinoline by wet oxidation—kinetic aspects and reaction mechanisms. Water Res 32:136–146
Thomsen MH, Hauggaard-Nielsen H (2008) Sustainable bioethanol production combining biorefinery principles using combined raw materials from wheat undersown with clover-grass. J Industrial Microbiol Biotechnol 35:303–311
Thomsen MH, Thygesen A, Christensen BH, Larsen J, Jørgensen H, Thomsen AB (2006) Preliminary results on optimising hydrothermal pre-treatment used in co-production of biofuels. Appl Biochem Biotechnol 129–132:448–460
Thomsen MH, Thygesen A, Thomsen AB (2008) Hydrothermal treatment of wheat straw at pilot plant scale using a three-step reactor system aiming at high hemicellulose recovery, high cellulose digestibility and low lignin hydrolysis. Bioresour Technol 99:4221–4228
Thygesen A, Oddershede J, Lilholt H, Thomsen AB, Ståhl K (2005) On the determination of crystallinity and cellulose content in plant fibres. Cellulose 12:563–576
Varga E, Klinke HB, Réczey K, Thomsen AB (2004) High solid simultaneous saccharification and fermentation of wet oxidized corn stover to ethanol. Biotechnol Bioeng 88:567–574
Wahlbom CF, van Zyl WH, Jönsson LJ, Hähn-Hägerdal B, Otero RRC (2003) Generation of the improved recombinant xylose-utilizing Saccharomyces cerevisiae TMB 3400 by random mutagenesis and physiological comparison with Pichia stipitis CBS 6054. Fems Yeast Research 3:319–326
Zaldivar J, Martinez A, Ingram LO (2000) Effect of alcohol compounds found in hemicellulose hydrolysate on the growth and fermentation of ethanologenic Escherichia coli. Biotechnol Bioeng 68:524–530
Zhao J, Wang M, Yang Z, Yang Z (2005) Measurement of inhibitory effects of furfural and furfural alcohol using coupled redox mediators. Enz Microb Technol 37:246–253
Acknowledgments
The work was financially supported by EU-contract ENK6-CT-2002–00650 and Danish project: PSO-F&U-project 2006-1-6412. Børge Holm Christensen (Sicco K/S, Denmark), Jan Larsen, Mai Østergaard Petersen, and Erik Hedahl-Frank (DONG Energy, Denmark) are thanked for collaboration on pretreatment experiments on the pilot plant, and Tomas Fernqvist and Ingelis Larsen (Technical University of Denmark) are thanked for technical assistance on analytical work.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Thomsen, M.H., Thygesen, A. & Thomsen, A.B. Identification and characterization of fermentation inhibitors formed during hydrothermal treatment and following SSF of wheat straw. Appl Microbiol Biotechnol 83, 447–455 (2009). https://doi.org/10.1007/s00253-009-1867-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00253-009-1867-1