Process options for the recovery of a pentosan-enriched fraction from wheat-based bioethanol thin stillage

Abstract

Aim

Stillage, the main residue from cereal-based bioethanol production, offers a great potential for the recovery of pentosan-type carbohydrates. Therefore, potential process options for the recovery of pentosans from bioethanol thin stillage are investigated and their basic feasibility is demonstrated on a laboratory scale.

Findings

The main result of this work is the development of a three-stage process for pentosan recovery, including solid–liquid separation, pentosan solubilisation and purification. The pentosan content of the thin stillage used here was determined to be about 14% related to dry matter (DM). By means of solid–liquid separation, these pentosans accumulate in the liquid phase (up to 80%), while the remainder (about 20%) is found in the solid phase. Solubilisation of these insoluble pentosans was achieved by using either a hydrothermal, an alkaline or an enzymatic treatment. Here, the results indicate a maximum solubilisation yield of 90% with a hydrothermal treatment using liquid hot water at 180 °C. Ultrafiltration and precipitation are investigated for purification. The most promising process option in this study is solid–liquid separation followed by ultrafiltration. In this case, the total pentosan yield is assessed to be about 48% (based on thin stillage) with a final pentosan concentration of about 30%DM.

Keywords

Stillage / Pentosan determination / Pentosan recovery / Pentosan solubilisation / Distillers’ grains / Ethanol

References

[1] Alyassin M (2019) Arabinoxylan prebiotic co-production within integrated biorefineries. Doctoral thesis, University of Huddersfield

[2] Anderson C, Simsek S. A novel combination of methods for the extraction and purification of arabinoxylan from byproducts of the cereal industry. Food Measure, 2019, 13: 1049-1057.

[3] Barros CP, Silva R, Guimarães JT, Balhtazar CF, Verruck S, Pimentel TC, Esmerino EA, Freitas MQ, Duarte MCK, Silva MC, Da Cruz AG. Chhikara N, Panghal A, Chaudhary G. Prebiotics and synbiotics in functional foods. Functional foods, 2022 Wiley, 21-53.

[4] Belitz H-D, Grosch W, Schieberle P. Food chemistry, 2009, Berlin: Springer.

[5] Chatzifragkou A, Charalampopoulos D. Distiller’s dried grains with solubles (DDGS) and intermediate products as starting materials in biorefinery strategies. Sustainable recovery and reutilization of cereal processing by-products, 2018 Elsevier, 63-86.

[6] Chatzifragkou A, Kosik O, Prabhakumari PC, Lovegrove A, Frazier RA, Shewry PR, Charalampopoulos D. Biorefinery strategies for upgrading distillers’ dried grains with solubles (DDGS). Process Biochem, 2015, 50: 2194-2207.

[7] Flodman HR, Boyer EJ, Muthukumarappan A, Noureddini H. Extraction of soluble fiber from distillers’ grains. Appl Biochem Biotechnol, 2012, 166: 1070-1081.

[8] Kaltschmitt M, Hartmann H, Hofbauer H. Energie aus Biomasse, 2016, Berlin: Springer

[9] Kehili M, Schmidt LM, Reynolds W, Zammel A, Zetzl C, Smirnova I, Allouche N, Sayadi S. Biorefinery cascade processing for creating added value on tomato industrial by-products from Tunisia. Biotechnol Biofuels, 2016, 9: 261.

[10] Kim Y, Mosier NS, Hendrickson R, Ezeji T, Blaschek H, Dien B, Cotta M, Dale B, Ladisch MR. Composition of corn dry-grind ethanol by-products: DDGS, wet cake, and thin stillage. Bioresour Technol, 2008, 99: 5165-5176.

[11] Kosik O, Powers SJ, Chatzifragkou A, Prabhakumari PC, Charalampopoulos D, Hess L, Brosnan J, Shewry PR, Lovegrove A. Changes in the arabinoxylan fraction of wheat grain during alcohol production. Food Chem, 2017, 221: 1754-1762.

[12] Lamp A (2020) Proteingewinnung aus Bioethanolschlempe. Dissertation, Technische Universität Hamburg

[13] McIlvaine TC. A buffer solution for colorimetric comparison. J Biol Chem, 1921, 49: 183-186.

[14] Misailidis N, Campbell GM, Du C, Sadhukhan J, Mustafa M, Mateos-Salvador F, Weightman RM. Evaluating the feasibility of commercial arabinoxylan production in the context of a wheat biorefinery principally producing ethanol. Chem Eng Res Des, 2009, 87: 1239-1250.

[15] Pedersen MB, Dalsgaard S, Knudsen KB, Yu S, Lærke HN. Compositional profile and variation of distillers dried grains with solubles from various origins with focus on non-starch polysaccharides. Anim Feed Sci Technol, 2014, 197: 130-141.

[16] Pereira LMS, Milan TM, Tapia-Blácido DR. Using Response surface methodology (RSM) to optimize 2G bioethanol production: a review. Biomass Bioenergy, 2021, 151: 106166.

[17] Roberfroid M. Prebiotics: the concept revisited. J Nutr, 2007, 137: 830S-S837.

[18] Roth M, Jekle M, Becker T. Opportunities for upcycling cereal byproducts with special focus on Distiller's grains. Trends Food Sci Technol, 2019, 91: 282-293.

[19] Ruiz HA, Conrad M, Sun S-N, Sanchez A, Rocha GJM, Romaní A, Castro E, Torres A, Rodríguez-Jasso RM, Andrade LP, Smirnova I, Sun R-C, Meyer AS. Engineering aspects of hydrothermal pretreatment: from batch to continuous operation, scale-up and pilot reactor under biorefinery concept. Bioresour Technol, 2020, 299: 122685.

[20] Singh RD, Banerjee J, Arora A. Prebiotic potential of oligosaccharides: a focus on xylan derived oligosaccharides. Bioactive Carbohydr Diet Fibre, 2015, 5: 19-30.

[21] Sluiter A, Hames B, Ruiz R, Scarlata C, Sluiter J, Templeton D (2006) Determination of Sugars, Byproducts, and Degradation Products in Liquid Fraction Process Samples. NREL (LAP)

[22] Sluiter A, Hames B, Ruiz R, Scarlata C, Sluiter J, Templeton D, Crocker D (2008) Determination of Structural Carbohydrates and Lignin in Biomass. NREL (LAP)

[23] Swennen K, Courtin C, Vanderbruggen B, Vandecasteele C, Declour J. Ultrafiltration and ethanol precipitation for isolation of arabinoxylooligosaccharides with different structures. Carbohydr Polym, 2005, 62: 283-292.

[24] Zerback T, Schumacher B, Weinrich S, Hülsemann B, Nelles M. Hydrothermal pretreatment of wheat straw—evaluating the effect of substrate disintegration on the digestibility in anaerobic digestion. Processes, 2022, 10: 1048.

[25] Zimmermann A, Visscher C, Kaltschmitt M. Plant-based fructans for increased animal welfare: provision processes and remaining challenges. Biomass Conv Bioref, 2021

Funding

Bundesanstalt für Landwirtschaft und Ernährung(2813IP027)

Technische Universität Hamburg (3140)