Brewer's spent grain (BSG) accounts for approximately 85% of the total mass of solid by-products in the brewing industry and represents an important secondary raw material of future biorefineries. Currently, the main application of BSG is limited to the feed and food industry. There is a strong need to develop sustainable pretreatment and fractionation processes to obtain BSG hydrolysates that enable efficient biotransformation into biofuels, biomaterials, or biochemicals. This paper aims to provide a comprehensive insight into the availability of BSG, chemical properties, and current and potential applications juxtaposed with the existing and emerging markets of the pyramid of bio-based products in the context of sustainable and circular bioeconomy. An economic evaluation of BSG for the production of highly valuable products is presented in the context of sustainable and circular bioeconomy targeting the market of Central and Eastern European countries (BIOEAST region).

Czech Academy of Sciences Prague Czechia

Energy Institute Hrvoje Požar Zagreb Croatia

Faculty of Chemistry and Chemical Technology University of Ljubljana Ljubljana Slovenia

Faculty of Food Technology Osijek Josip Juraj Strossmayer University of Osijek Osijek Croatia

Lab of Biorefinery Shanghai Advanced Research Institute Chinese Academy of Sciences Pudong China

Zobrazit více v PubMed

Abd El-Hack M. E., Alagawany M., Patra A., Abdel-Latif M., Ashour E. A., Arif M., et al. (2019). Use of Brewers Dried Grains as an Unconventional Feed Ingredient in the Diets of Broiler Chickens: A Review. Adv. Anim. Vet. Sci. 7, 218–224. 10.17582/journal.aavs/2019/7.3.218.224 DOI

A. Dávila J., Rosenberg M., Rosenberg M., A. Cardona C. (2016). A Biorefinery Approach for the Production of Xylitol, Ethanol and Polyhydroxybutyrate from Brewer's Spent Grain. AIMS Agric. Food 1, 52–66. 10.3934/AGRFOOD.2016.1.52 DOI

Akita H., Nakashima N., Hoshino T. (2015). Bacterial Production of Isobutanol without Expensive Reagents. Appl. Microbiol. Biotechnol. 99, 991–999. 10.1007/s00253-014-6173-x PubMed DOI

Almeida A. D. R., Geraldo M. R. F., Ribeiro L. F., Silva M. V., Maciel M. V. D. O. B., Haminiuk C. W. I. (2017). Bioactive Compounds from Brewer's Spent Grain: Phenolic Compounds, Fatty Acids and In Vitro Antioxidant Capacity. Acta Sci. Technol. 39, 269–277. 10.4025/actascitechnol.v39i3.28435 DOI

Amirvaresi A., Nikounezhad N., Amirahmadi M., Daraei B., Parastar H. (2021). Comparison of Near-Infrared (NIR) and Mid-infrared (MIR) Spectroscopy Based on Chemometrics for Saffron Authentication and Adulteration Detection. Food Chem. 344, 128647. 10.1016/j.foodchem.2020.128647 PubMed DOI

Amoah K. O., Asiedu P., Wallace P., Bumbie G. Z., Rhule S. W. A. (2017). The Performance of Pigs at Different Phases of Growth on Sun-Dried Brewers Spent Grain. Livest. Res. Rural. Dev. 29, e90.

Amraoui Y., Prabhu A. A., Narisetty V., Coulon F., Kumar Chandel A., Willoughby N., et al. (2022). Enhanced 2,3-Butanediol Production by Mutant Enterobacter Ludwigii Using Brewers' Spent Grain Hydrolysate: Process Optimization for a Pragmatic Biorefinery Loom. Chem. Eng. J. 427, 130851. 10.1016/j.cej.2021.130851 DOI

Ashman C. H., Gao L., Goldfarb J. L. (2020). Silver Nitrate In Situ Upgrades Pyrolysis Biofuels from Brewer's Spent Grain via Biotemplating. J. Anal. Appl. Pyrolysis 146, 104729. 10.1016/j.jaap.2019.104729 DOI

Assefa Y., Jabasingh S. A. (2020). Lactic Acid Production from Brewer’s Spent Grain by Lactobacillus Plantarum ATCC 8014. J. Sci. Ind. Res. 79, 10–613.

Banjo T., Kareem S., Popoola T., Akinloye O. (2018). Microbial Production of Ascorbic Acid from Brewery Spent Grain (BSG). Food Appl. Biosci. J. 6, 93–105. 10.14456/fabj.2018.9 DOI

Bellido C., Loureiro Pinto M., Coca M., González-Benito G., García-Cubero M. T. (2014). Acetone-butanol-ethanol (ABE) Production by Clostridium Beijerinckii from Wheat Straw Hydrolysates: Efficient Use of Penta and Hexa Carbohydrates. Bioresour. Technol. 167, 198–205. 10.1016/j.biortech.2014.06.020 PubMed DOI

Bianco A., Fancello F., Garau M., Deroma M., Atzori A. S., Castaldi P., et al. (2022). Microbial and Chemical Dynamics of Brewers' Spent Grain during a Low-Input Pre-vermicomposting Treatment. Sci. Total Environ. 802, 149792. 10.1016/j.scitotenv.2021.14910.1016/j.scitotenv.2021.149792 PubMed DOI

Bio-based Industries Joint Undertaking (2020). Bio-based Industries Joint Undertaking . https://www.bbi.europa.eu/search/node/lignocellulosic%20type%3Aprojects%20%22food (Accessed June 15, 2021).

BIOEAST (2021). The Central-Eastern European Initiative for Knowledge-Based Agriculture, Aquaculture and Forestry in the Bioeconomy . https://bioeast.eu/home/(Accessed April 14, 2021).

Birner R. (2018). “Bioeconomy Concepts,” in Bioeconomy. Editor Lewandowski I. (Cham: Springer; ), 17–38. 10.1007/978-3-319-68152-8_3 DOI

Birsan R. I., Wilde P., Waldron K. W., Rai D. K. (2019). Recovery of Polyphenols from Brewer's Spent Grains. Antioxidants 8, 380. 10.3390/antiox8090380 PubMed DOI PMC

Bravi E., Francesco G. D., Sileoni V., Perretti G., Galgano F., Marconi O. (2021). Brewing By-Product Upcycling Potential: Nutritionally Valuable Compounds and Antioxidant Activity Evaluation. Antioxidants 10, 165. 10.3390/antiox10020165 PubMed DOI PMC

Caetano N. S., Moura R. F., Meireles S., Mendes A. M., Mata T. M. (2013). Bioethanol from Brewer’s Spent Grains: Acid Pretreatment Optimization. Chem. Eng. Trans. 35, 1021–1026. 10.3303/CET1335170 DOI

Castilla-Archilla J., Papirio S., Lens P. N. L. (2021). Two Step Process for Volatile Fatty Acid Production from Brewery Spent Grain: Hydrolysis and Direct Acidogenic Fermentation Using Anaerobic Granular Sludge. Process Biochem. 100, 272–283. 10.1016/j.procbio.2020.10.011 DOI

Castro L. E. N., Colpini L. M. S. (2021). All-around Characterization of Brewers' Spent Grain. Eur. Food Res. Technol. 247, 3013–3021. 10.1007/s00217-021-03860-5 DOI

Chanzu H. A., Onyari J. M., Shiundu P. M. (2019). Brewers' Spent Grain in Adsorption of Aqueous Congo Red and Malachite Green Dyes: Batch and Continuous Flow Systems. J. Hazard. Mater. 380, 120897. 10.1016/j.jhazmat.2019.120897 PubMed DOI

Chilakamarry C. R., Mimi Sakinah A. M., Zularisam A. W., Sirohi R., Khilji I. A., Ahmad N., et al. (2022). Advances in Solid-State Fermentation for Bioconversion of Agricultural Wastes to Value-Added Products: Opportunities and Challenges. Bioresour. Technol. 343, 126065. 10.1016/j.biortech.2021.126065 PubMed DOI

Combest S., Warren C., Patterson M. (2020). Upcycling Brewers' Spent Grain: The Development of Muffins and Biomarker Response after Consuming Muffins for 8-Weeks in Healthy Adults from Randomized-Controlled Trial. Curr. Dev. Nutr. 4, 745. 10.1093/cdn/nzaa052_014 DOI

Cooray S. T., Chen W. N. (2018). Valorization of Brewer's Spent Grain Using Fungi Solid-State Fermentation to Enhance Nutritional Value. J. Funct. Foods 42, 85–94. 10.1016/j.jff.2017.12.027 DOI

Corchado-Lopo C., Martínez-Avila O., Marti E., Llimós J., Busquets A. M., Kucera D., et al. (2021). Brewer's Spent Grain as a No-Cost Substrate for Polyhydroxyalkanoates Production: Assessment of Pretreatment Strategies and Different Bacterial Strains. New Biotechnol. 62, 60–67. 10.1016/j.nbt.2021.01.009 PubMed DOI

Datta R., Henry M. (2006). Lactic Acid: Recent Advances in Products, Processes and Technologies - a Review. J. Chem. Technol. Biotechnol. 81, 1119–1129. 10.1002/jctb.1486 DOI

Denstadli V., Westereng B., Biniyam H. G., Ballance S., Knutsen S. H., Svihus B. (2010). Effects of Structure and Xylanase Treatment of Brewers' Spent Grain on Performance and Nutrient Availability in Broiler Chickens. Br. Poult. Sci. 51, 419–426. 10.1080/00071668.2010.495745 PubMed DOI

Dhillon G. S., Kaur S., Brar S. K. (2012). In-vitro Decolorization of Recalcitrant Dyes through an Ecofriendly Approach Using Laccase from Trametes versicolor Grown on Brewer's Spent Grain. Int. Biodeterior. Biodegrad. 72, 67–75. 10.1016/j.ibiod.2012.05.012 DOI

Directorate-General for Research and Innovation (European Commission) (2018). A Sustainable Bioeconomy for Europe: Strengthening the Connection between Economy, Society and the Environment: Updated Bioeconomy Strategy. Brussels: Publications Office of the European Union.

Dos Santos Costa R., de Almeida S. S., Cavalcanti E. d. A. C., Freire D. M. G., Moura-Nunes N., Monteiro M., et al. (2021). Per Rone, DEnzymes Produced by Solid State Fermentation of Agro-Industrial By-Products Release Ferulic Acid in Bioprocessed Whole-Wheat Breads. Food Res. Int. 140, 109843. 10.1016/j.foodres.2020.109843 PubMed DOI

Dudek M., Świechowski K., Manczarski P., Koziel J. A., Białowiec A. (2019). The Effect of Biochar Addition on the Biogas Production Kinetics from the Anaerobic Digestion of Brewers' Spent Grain. Energies 12, 1518. 10.3390/en12081518 DOI

Eliopoulos C., Arapoglou D., Chorianopoulos N., Markou G., Haroutounian S. A. (2021). Conversion of Brewers' Spent Grain into Proteinaceous Animal Feed Using Solid State Fermentation. Environ. Sci. Pollut. Res. 29, 29562–29569. 10.1007/s11356-021-15495-w PubMed DOI

Faccenda A., Zambom M. A., Castagnara D. D., Avila A. S. d., Fernandes T., Eckstein E. I., et al. (2017). Use of Dried Brewers' Grains Instead of Soybean Meal to Feed Lactating Cows. R. Bras. Zootec. 46, 39–46. 10.1590/S1806-92902017000100007 DOI

Farcas A. C., Socaci S. A., Chiș M. S., Pop O. L., Fogarasi M., Păucean A., et al. (2021). Reintegration of Brewers Spent Grains in the Food Chain: Nutritional, Functional and Sensorial Aspects. Plants 10, 2504. 10.3390/plants10112504 PubMed DOI PMC

Femi-Ola T. O., Atere V. A. (2012). Citric Acid Production from Brewers Spent Grain by Aspergillus niger and Saccharomyces cerevisiae . Int. J. Biosci. 2, 30–36.

Fernandes H., Moyano F., Castro C., Salgado J., Martínez F., Aznar M., et al. (2021). Solid-state Fermented Brewer's Spent Grain Enzymatic Extract Increases In Vitro and In Vivo Feed Digestibility in European Seabass. Sci. Rep. 11, 1–15. 10.1038/s41598-021-02393-x PubMed DOI PMC

Garrett R., Bellmer D., McGlynn W., Rayas-Duarte P. (2021). Development of New Chip Products from Brewer's Spent Grain. J. Food Qual. 2021, 1–6. 10.1155/2021/5521746 DOI

Giacobbe S., Piscitelli A., Raganati F., Lettera V., Sannia G., Marzocchella A., et al. (2019). Butanol Production from Laccase-Pretreated Brewer's Spent Grain. Biotechnol. Biofuels. 12, e47. 10.1186/s13068-019-1383-1 PubMed DOI PMC

Gregori A. (2014). Cordycepin Production by Cordyceps Militaris Cultivation on Spent Brewery Grains. Acta Biol. Slov. 57, 45–52.

Gupta M., Abu-Ghannam N., Gallaghar E. (2010). Barley for Brewing: Characteristic Changes during Malting, Brewing and Applications of its By-Products. Compr. Rev. Food Sci. Food Saf. 9, 318–328. 10.1111/j.1541-4337.2010.00112.x PubMed DOI

Hashemi M., Razavi S. H., Shojaosadati S. A., Mousavi S. M. (2011). The Potential of Brewer's Spent Grain to Improve the Production of α-amylase by Bacillus Sp. KR-8104 in Submerged Fermentation System. New Biotechnol. 28, 165–172. 10.1016/j.nbt.2010.10.009 PubMed DOI

Hassan S. S., Tiwari B. K., Williams G. A., Jaiswal A. K. (2020). Bioprocessing of Brewers' Spent Grain for Production of Xylanopectinolytic Enzymes by Mucor Sp . Bioresour. Technol. Rep. 9, 100371. 10.1016/j.biteb.2019.100371 DOI

Heredia-Olea E., Pérez-Carrillo E., Serna-Saldívar S. O. (2015). Effect of Extrusion Conditions and Hydrolysis with Fiber-Degrading Enzymes on the Production of C5 and C6 Sugars from Brewers' Spent Grain for Bioethanol Production. Biofuel Res. J. 5, 203–208. 10.18331/BRJ2015.2.1.6 DOI

Ibarruri J., Cebrián M., Hernández I. (2019). Solid State Fermentation of Brewer's Spent Grain Using Rhizopus Sp. To Enhance Nutritional Value. Waste Biomass Valor 10, 3687–3700. 10.1007/s12649-019-00654-5 DOI

Ikram S., Huang L., Zhang H., Wang J., Yin M. (2017). Composition and Nutrient Value Proposition of Brewers Spent Grain. J. Food Sci. 82, 2232–2242. 10.1111/1750-3841.13794 PubMed DOI

Izinyon O., Nwosu O., Akhigbe L., Ilaboya I. (2016). Performance Evaluation of Fe (Iii) Adsorption onto Brewers' Spent Grain. Nig. J. Tech. 35, 970. 10.4314/njt.v35i4.36 DOI

Jaeger A., Zannini E., Sahin A. W., Arendt E. K. (2021). Barley Protein Properties, Extraction and Applications, with a Focus on Brewers' Spent Grain Protein. Foods 10, 1389. 10.3390/foods10061389 PubMed DOI PMC

Jaguey-Hernández Y., Tapia-Ignacio C., Aguilar-Arteaga K., González-Olivares L. G., Castañeda-Ovando E. P., Cruz-Cansino N., et al. (2022). Thermoplastic Biofilms Obtained from an Arabinoxylan-Rich Fraction from Brewers' Spent Grain: Physicochemical Characterization and Thermal Analysis. Biomass Conv. bioref. 2022, 1–13. 10.1007/s13399-021-02288-x DOI

Johnson P., Paliwal J., Cenkowski S. (2010). Issues with Utilisation of Brewers' Spent Grain. Stewart Postharvest Rev. 6, 1–8. 10.2212/spr.2010.4.2 DOI

Karp S. G., Bittencourt Sydney E., Lorenci Woiciechowski A., Letti L. A. J., de Carvalho J. C., Zevallos Torres L. A., et al. (2021). “Lignocellulosic Biorefinery for Value-Added Products: the Emerging Bioeconomy,” in Circular Bioeconomy - Current Status and Future Outlook. Editors Pandey A., Tyagi R.D., Varjani S. (Elsevier; ), 291–321. 10.1016/b978-0-12-821878-5.00002-7 DOI

Kavalopoulos M., Stoumpou V., Christofi A., Mai S., Barampouti E. M., Moustakas K., et al. (2021). Sustainable Valorisation Pathways Mitigating Environmental Pollution from Brewers' Spent Grains. Environ. Pollut. 270, 116069. 10.1016/j.envpol.2020.116069 PubMed DOI

Kezerle A., Velić N., Hasenay D., Kovačević D. (2018). Lignocellulosic Materials as Dye Adsorbents: Adsorption of Methylene Blue and Congo Red on Brewers' Spent Grain. Croat. Chem. Acta 91, 53–64. 10.5562/cca3289 DOI

Krasznai D. J., Champagne Hartley R., Roy H. M., Champagne P., Cunningham M. F. (2017). Compositional Analysis of Lignocellulosic Biomass: Conventional Methodologies and Future Outlook. Crit. Rev. Biotechnol. 38, 199–217. 10.1080/07388551.2017.1331336 PubMed DOI

Kulisic B., Lier M., Perović M., Matijašević N., Mandarić A., Sauvula-Seppälä T. (2020). D 1.2: Report on Analysis of BIOEAST National Bioeconomy Related Sectors. Horizon 2020 Project: Advancing Sustainable Circular Bioeconomy in Central and Eastern European Countries. BIOEASTsUP.

Lao E. J., Dimoso N., Raymond J., Mbega E. R. (2020). The Prebiotic Potential of Brewers' Spent Grain on Livestock's Health: a Review. Trop. Anim. Health Prod. 52, 461–472. 10.1007/s11250-019-02120-9 PubMed DOI

Leite P., Sousa D., Fernandes H., Ferreira M., Costa A. R., Filipe D., et al. (2021). Recent Advances in Production of Lignocellulolytic Enzymes by Solid-State Fermentation of Agro-Industrial Wastes. Curr. Opin. Green Sustain. Chem. 27, 100407. 10.1016/j.cogsc.2020.100407 DOI

Li Q., Chai L., Yang Z., Wang Q., Wang Y. (2010). A Comparative Study of Ag(I) Adsorption on Raw and Modified Spent Grain: Kinetic and Thermodynamic Aspects. Water Environ. Res. 82, 2290–2296. 10.2175/106143010x12681059116978 PubMed DOI

Liguori R., Soccol C. R., Vandenberghe L. P. d. S., Woiciechowski A. L., Marcolongo L., et al. (2015). Selection of the StrainLactobacillus acidophilusATCC 43121 and its Application to Brewers' Spent Grain Conversion into Lactic Acid. BioMed Res. Int. 2015, 9. 10.1155/2015/240231 PubMed DOI PMC

Lin P. P., Mi L., Morioka A. H., Yoshino K. M., Konishi S., Xu S. C., et al. (2015). Consolidated Bioprocessing of Cellulose to Isobutanol Using Clostridium Thermocellum . Metab. Eng. 31, 44–52. 10.1016/j.ymben.2015.07.001 PubMed DOI

Llimós J., Martínez-Avila O., Marti E., Corchado-Lopo C., Llenas L., Gea T., et al. (2020). Brewer's Spent Grain Biotransformation to Produce Lignocellulolytic Enzymes and Polyhydroxyalkanoates in a Two-Stage Valorization Scheme. Biomass Conv. bioref. 10.1007/s13399-020-00918-4 DOI

Lynch K. M., Steffen E. J., Arendt E. K. (2016). Brewers' Spent Grain: a Review with an Emphasis on Food and Health. J. Inst. Brew. 122, 553–568. 10.1002/jib.363 DOI

Lynch K. M., Strain C. R., Johnson C., Patangia D., Stanton C., Koc F., et al. (2021). Extraction and Characterisation of Arabinoxylan from Brewers Spent Grain and Investigation of Microbiome Modulation Potential. Eur. J. Nutr. 60, 4393–4411. 10.1007/s00394-021-02570-8 PubMed DOI PMC

Machado C. M. M., Soccol C. R., de Oliveira B. H., Pandey A. (2021). Gibberellic Acid Production by Solid-State Fermentation in Coffee Husk. Abab 102-103, 179–192. 10.1385/abab:102-103:1-6:179 PubMed DOI

Malomo O., Daniels A. O., Olajiga O., Femi- Ola T. O., Alamu A. E. (2013). The Use of Brewer′S Spent Grains in the Cultivation of Some Fungal Isolates. Ijnfs 2, 5–9. 10.11648/j.ijnfs.20130201.12 DOI

Mandalari G., Bisignano G., Lo Curto R. B., Waldron K. W., Faulds C. B. (2008). Production of Feruloyl Esterases and Xylanases by Talaromyces stipitatus and Humicola Grisea Var. Thermoidea on Industrial Food Processing By-Products. Bioresour. Technol. 99, 5130–5133. 10.1016/j.biortech.2007.09.022 PubMed DOI

Marcus A., Fox G. (2021). Fungal Biovalorization of a Brewing Industry Byproduct, Brewer's Spent Grain: A Review. Foods 10, 2159. 10.3390/foods10092159 PubMed DOI PMC

Mata T. M., Tavares T. F., Meireles S., Caetano N. S. (2015). Bioethanol from Brewers’ Spent Grain: Pentose Fermentation. Chem. Eng. Trans. 43, 241–246. 10.3303/CET1543041 DOI

Meneses N. G. T., Martins S., Teixeira J. A., Mussatto S. I. (2013). Influence of Extraction Solvents on the Recovery of Antioxidant Phenolic Compounds from Brewer's Spent Grains. Sep. Purif. Technol. 108, 152–158. 10.1016/j.seppur.2013.02.015 DOI

Minty J. J., Singer M. E., Scholz S. A., Bae C.-H., Ahn J.-H., Foster C. E., et al. (2013). Design and Characterization of Synthetic Fungal-Bacterial Consortia for Direct Production of Isobutanol from Cellulosic Biomass. Proc. Natl. Acad. Sci. U.S.A. 110, 14592–14597. 10.1073/pnas.1218447110 PubMed DOI PMC

Moher D., Liberati A., Tetzlaff J., Altman D. G. (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med. 6, e1000097. 10.1371/journal.pmed.1000097 PubMed DOI PMC

Moher D., Shamseer L., Shamseer L., Clarke M., Ghersi D., Liberati A., et al. (2015). Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 Statement. Syst. Rev. 4, 1. 10.1186/2046-4053-4-1 PubMed DOI PMC

Moran-Aguilar M. G., Costa-Trigo I., Calderón-Santoyo M., Domínguez J. M., Aguilar-Uscanga M. G. (2021). Production of Cellulases and Xylanases in Solid-State Fermentation by Different Strains of Aspergillus niger Using Sugarcane Bagasse and Brewery Spent Grain. Biochem. Eng. J. 172, 108060. 10.1016/j.bej.2021.108060 DOI

Mussatto S. I., Dragone G., Roberto I. C. (2007a). Ferulic and P-Coumaric Acids Extraction by Alkaline Hydrolysis of Brewer's Spent Grain. Industrial Crops Prod. 25, 231–237. 10.1016/j.indcrop.2006.11.001 DOI

Mussatto S. I., Fernandes M., Dragone G., Mancilha I. M., Roberto I. C. (2007b). Brewer's Spent Grain as Raw Material for Lactic Acid Production by Lactobacillus Delbrueckii. Biotechnol. Lett. 29, 1973–1976. 10.1007/s10529-007-9494-3 PubMed DOI

Mussatto S. I., Roberto I. C. (2005). Acid Hydrolysis and Fermentation of Brewer's Spent Grain to Produce Xylitol. J. Sci. Food Agric. 85, 2453–2460. 10.1002/jsfa.2276 DOI

Nagy V., Diósi G. (2021). Using Brewer's Spent Grain as a Byproduct of the Brewing Industry in the Bakery Industry. Évik 67, 3339–3350. 10.52091/EVIK-2021/1-5-ENG DOI

Naibaho J., Butula N., Jonuzi E., Korzeniowska M., Laaksonen O., Föste M., et al. (2022). Potential of Brewers' Spent Grain in Yogurt Fermentation and Evaluation of its Impact in Rheological Behaviour, Consistency, Microstructural Properties and Acidity Profile during the Refrigerated Storage. Food Hydrocoll. 125, 107412. 10.1016/j.foodhyd.2021.107412 DOI

Naibaho J., Korzeniowska M. (2021). The Variability of Physico-Chemical Properties of Brewery Spent Grain from 8 Different Breweries. Heliyon 7, e06583. 10.1016/j.heliyon.2021.e06583 PubMed DOI PMC

Nazzaro J., Martin D. S., Perez-Vendrell A. M., Padrell L., Iñarra B., Orive M., et al. (2021). Apparent Digestibility Coefficients of Brewer's By-Products Used in Feeds for Rainbow Trout (Oncorhynchus mykiss) and Gilthead Seabream (Sparus aurata). Aquaculture 530, 735796. 10.1016/j.aquaculture.2020.735796 DOI

Neylon E., Arendt E. K., Zannini E., Sahin A. W. (2021). Fermentation as a Tool to Revitalise Brewers' Spent Grain and Elevate Techno-Functional Properties and Nutritional Value in High Fibre Bread. Foods 10, 1639. 10.3390/foods10071639 PubMed DOI PMC

Olugbenga A. O., Ibiyemi I. O. (2011). Bioethanol Production from Brewer’s Spent Grain, Bread Wastes and Corn Fiber. Afr. J. Food Sci. 5, 148–155.

Ortiz I., Torreiro Y., Molina G., Maroño M., Sánchez J. M. (2019). A Feasible Application of Circular Economy: Spent Grain Energy Recovery in the Beer Industry. Waste Biomass Valor 10, 3809–3819. 10.1007/s12649-019-00677-y DOI

Outeiriño D., Costa-Trigo I., Pinheiro de Souza Oliveira R., Pérez Guerra N., Domínguez J. M. (2019). A Novel Approach to the Biorefinery of Brewery Spent Grain. Process Biochem. 85, 135–142. 10.1016/j.procbio.2019.06.007 DOI

Pabbathi N. P. P., Velidandi A., Pogula S., Gandam P. K., Baadhe R. R., Sharma M., et al. (2022). Brewer's Spent Grains-Based Biorefineries: A Critical Review. Fuel 317, 123435. 10.1016/j.fuel.2022.123435 DOI

Panagiotou G., Granouillet P., Olsson L. (2006). Production and Partial Characterization of Arabinoxylan-Degrading Enzymes by Penicillium brasilianum under Solid-State Fermentation. Appl. Microbiol. Biotechnol. 72, 1117–1124. 10.1007/s00253-006-0394-6 PubMed DOI

Panjičko M., Zupančič G. D., Fanedl L., Logar R. M., Tišma M., Zelić B. (2017). Biogas Production from Brewery Spent Grain as a Mono-Substrate in a Two-Stage Process Composed of Solid-State Anaerobic Digestion and Granular Biomass Reactors. J. Clean. Prod. 166, 519–529. 10.1016/j.jclepro.2017.07.197 DOI

Parchami M., Ferreira J. A., Taherzadeh M. J. (2021). Starch and Protein Recovery from Brewer's Spent Grain Using Hydrothermal Pretreatment and Their Conversion to Edible Filamentous Fungi - A Brewery Biorefinery Concept. Bioresour. Technol. 337, 125409. 10.1016/j.biortech.2021.125409 PubMed DOI

Pathania S., Sharma S., Kumari K. (2018). Solid State Fermentation of BSG for Citric Acid Production. Indian J. Nat. Prod. Resour. 9, 70–74.

Plaza P. E., Gallego-Morales L. J., Peñuela-Vásquez M., Lucas S., García-Cubero M. T., Coca M. (2017). Biobutanol Production from Brewer's Spent Grain Hydrolysates by Clostridium Beijerinckii . Bioresour. Technol. 244, 166–174. 10.1016/j.biortech.2017.07.139 PubMed DOI

Proaño J. L., Salgado P. R., Cian R. E., Mauri A. N., Drago S. R. (2020). Physical, Structural and Antioxidant Properties of Brewer's Spent Grain Protein Films. J. Sci. Food Agric. 100, 5458–5465. 10.1002/jsfa.10597 PubMed DOI

Puligundla P., Mok C. (2021). Recent Advances in Biotechnological Valorization of Brewers' Spent Grain. Food Sci. Biotechnol. 30, 341–353. 10.1007/s10068-021-00900-4 PubMed DOI PMC

Pullin A. S., Stewart G. B. (2007). Guidelines for Systematic Review in Conservation and Environmental Management. Conserv. Biol. 20, 1647–1656. 10.1111/j.1523-1739.2006.00485.x PubMed DOI

Qiu L., Li J.-J., Li Z., Wang J.-J. (2019). Production and Characterization of Biocontrol Fertilizer from Brewer's Spent Grain via Solid-State Fermentation. Sci. Rep. 9, e480. 10.1038/s41598-018-36949-1 PubMed DOI PMC

Radzik-Rant A., Rant W., Niżnikowski R., Świątek M., Szymańska Ż., Ślęzak M., et al. (2018). The Effect of the Addition of Wet Brewers Grain to the Diet of Lambs on Body Weight Gain, Slaughter Valueand Meat Quality. Arch. Anim. Breed. 61, 245–251. 10.5194/aab-61-245-2018 DOI

Rahman M. J., Malunga L. N., Eskin M., Eck P., Thandapilly S. J., Thiyam-Hollander U. (2021). Valorization of Heat-Treated Brewers' Spent Grain through the Identification of Bioactive Phenolics by UPLC-PDA and Evaluation of Their Antioxidant Activities. Front. Nutr. 8, 519. 10.3389/fnut.2021.634519 PubMed DOI PMC

Ravindran R., Williams G. A., Jaiswal A. K. (2019). Evaluation of Brewer's Spent Grain Hydrolysate as a Substrate for Production of Thermostable α-amylase by Bacillus Stearothermophilus. Bioresour. Technol. Rep. 5, 141–149. 10.1016/j.biteb.2019.01.004 DOI

Rego F., Soares Dias A. P., Casquilho M., Rosa F. C., Rodrigues A. (2019). Fast Determination of Lignocellulosic Composition of Poplar Biomass by Thermogravimetry. Biomass Bioenergy 122, 375–380. 10.1016/j.biombioe.2019.01.037 DOI

Rojas-Chamorro J. A., Romero I., López-Linares J. C., Castro E. (2020). Brewer's Spent Grain as a Source of Renewable Fuel through Optimized Dilute Acid Pretreatment. Renew. Energy 148, 81–90. 10.1016/j.renene.2019.12.030 DOI

Saba S., Zara G., Bianco A., Garau M., Bononi M., Deroma M., et al. (2019). Comparative Analysis of Vermicompost Quality Produced from Brewers' Spent Grain and Cow Manure by the Red Earthworm Eisenia fetida . Bioresour. Technol. 293, 122019. 10.1016/j.biortech.2019.122019 PubMed DOI

Sajib M., Falck P., Sardari R. R. R., Mathew S., Grey C., Karlsson E. N., et al. (2018). Valorization of Brewer's Spent Grain to Prebiotic Oligosaccharide: Production, Xylanase Catalyzed Hydrolysis, In-Vitro Evaluation with Probiotic Strains and in a Batch Human Fecal Fermentation Model. J. Biotechnol. 268, 61–70. 10.1016/j.jbiotec.2018.01.005 PubMed DOI

Salvador R., Puglieri F. N., Halog A., Andrade F. G. d., Piekarski C. M., De Francisco A. C. (2021). Key Aspects for Designing Business Models for a Circular Bioeconomy. J. Clean. Prod. 278, 124341. 10.1016/j.jclepro.2020.124341 DOI

Schettino R., Verni M., Acin-Albiac M., Vincentini O., Krona A., Knaapila A., et al. (2021). Bioprocessed Brewers' Spent Grain Improves Nutritional and Antioxidant Properties of Pasta. Antioxidants 10, 742. 10.3390/antiox10050742 PubMed DOI PMC

Šelo G., Planinić M., Tišma M., Tomas S., Koceva Komlenić D., Bucić-Kojić A. (2021). A Comprehensive Review on Valorization of Agro-Food Industrial Residues by Solid-State Fermentation. Foods 10, 927. 10.3390/foods10050927 PubMed DOI PMC

Sganzerla W. G., Ampese L. C., Mussatto S. I., Forster‐Carneiro T. (2021a). A Bibliometric Analysis on Potential Uses of Brewer's Spent Grains in a Biorefinery for the Circular Economy Transition of the Beer Industry. Biofuels, Bioprod. Bioref. 15, 1965–1988. 10.1002/bbb.2290 DOI

Sganzerla W. G., Buller L. S., Mussatto S. I., Forster-Carneiro T. (2021b). Techno-economic Assessment of Bioenergy and Fertilizer Production by Anaerobic Digestion of Brewer's Spent Grains in a Biorefinery Concept. J. Clean. Prod. 297, 126600. 10.1016/j.jclepro.2021.126600 DOI

Sibhatu H. K., Anuradha Jabasingh S., Yimam A., Ahmed S. (2021). Ferulic Acid Production from Brewery Spent Grains, an Agro-Industrial Waste. Lwt 135, 110009. 10.1016/j.lwt.2020.110009 DOI

Silbir S., Goksungur Y. (2019). Natural Red Pigment Production by Monascus Purpureus in Submerged Fermentation Systems Using a Food Industry Waste: Brewer's Spent Grain. Foods 8, 161. 10.3390/foods8050161 PubMed DOI PMC

Silva E. G., Borges A. S., Maione N. R., Castiglioni G. L., Suarez C. A. G., Montano I. D. C. (2019). Fermentation of Hemicellulose Liquor from Brewer's Spent Grain Using Scheffersomyces Stipitis and Pachysolen Tannophilus for Production of 2G Ethanol and Xylitol. Biofuels, Bioprod. Bioref. 14, 127–137. 10.1002/bbb.2072 DOI

Statista (2021). Beer Production Worldwide in 2020, by Region (In Million Hectoliters) . https://www.statista.com/statistics/202417/beer-output-volumes-of-the-different-continents-in-2010/(Accessed March 12, 2022).

Stelick A., Sogari G., Rodolfi M., Dando R., Paciulli M. (2021). Impact of Sustainability and Nutritional Messaging on Italian Consumers' Purchase Intent of Cereal Bars Made with Brewery Spent Grains. J. Food Sci. 86, 531–539. 10.1111/1750-3841.15601 PubMed DOI

Tan Y. X., Mok W. K., Lee J., Kim J., Chen W. N. (2019). Solid State Fermentation of Brewers' Spent Grains for Improved Nutritional Profile Using Bacillus Subtilis WX-17. Fermentation 5, 52. 10.3390/fermentation5030052 DOI

Tanoue Batista M. C., Soccol C. R., Spier M. R., Libardi Junior N., Porto de Souza Vandenberghe L. (2021). Potential Application of Dextranase Produced by Penicillium aculeatum in Solid-State Fermentation from Brewer's Spent Grain in Sugarcane Process Factories. Biocatal. Agric. Biotechnol. 35, 102086. 10.1016/j.bcab.2021.102086 DOI

Terrasan C. R. F., Carmona E. C. (2015). Solid-state Fermentation of Brewer's Spent Grain for Xylanolytic Enzymes Production by Penicillium janczewskii and Analyses of the Fermented Substrate. Biosci. J. 31, 1826–1836. 10.14393/BJ-v31n6a2015-30044 DOI

The Brewers of Europe (2019). Country Profiles . https://brewersofeurope.org/site/countries/key-facts-figures.php (Accessed April 14, 2021).

Tišma M., Bucić-Kojić A., Planinić M. (2021a). Bio-based Products from Lignocellulosic Waste Biomass. Chem. Biochem. Eng. Q. (Online) 35, 139–156. 10.15255/CABEQ.2021.1931 DOI

Tišma M., Jurić A., Bucić-Kojić A., Panjičko M., Planinić M. (2018). Biovalorization of Brewers' Spent Grain for the Production of Laccase and Polyphenols. J. Inst. Brew. 124, 182–186. 10.1002/jib.479 DOI

Tišma M., Žnidaršič-Plazl P., Šelo G., Tolj I., Šperanda M., Bucić-Kojić A., et al. (2021b). Trametes versicolor in Lignocellulose-Based Bioeconomy: State of the Art, Challenges and Opportunities. Bioresour. Technol. 330, 124997. 10.1016/j.biortech.2021.124997 PubMed DOI

Wilkinson S., Smart K. A., Cook D. J. (2014). Optimisation of Alkaline Reagent Based Chemical Pre-treatment of Brewers Spent Grains for Bioethanol Production. Industrial Crops Prod. 62, 219–227. 10.1016/j.indcrop.2014.08.036 DOI

Wohlgemuth R. (2021). Biocatalysis - Key Enabling Tools from Biocatalytic One-step and Multi-step Reactions to Biocatalytic Total Synthesis. New Biotechnol. 60, 113–123. 10.1016/j.nbt.2020.08.006 PubMed DOI

Wolters N., Schabronath C., Schembecker G., Merz J. (2016). Efficient Conversion of Pretreated Brewer's Spent Grain and Wheat Bran by Submerged Cultivation of Hericium erinaceus. Bioresour. Technol. 222, 123–129. 10.1016/j.biortech.2016.09.121 PubMed DOI

Xiros C., Christakopoulos P. (2012). Biotechnological Potential of Brewers Spent Grain and its Recent Applications. Waste Biomass Valor 3, 213–232. 10.1007/s12649-012-9108-8 DOI

Xiros C., Topakas E., Katapodis P., Christakopoulos P. (2008a). Evaluation of Fusarium Oxysporum as an Enzyme Factory for the Hydrolysis of Brewer's Spent Grain with Improved Biodegradability for Ethanol Production. Industrial Crops Prod. 28, 213–224. 10.1016/j.indcrop.2008.02.004 DOI

Xiros C., Topakas E., Katapodis P., Christakopoulos P. (2008b). Hydrolysis and Fermentation of Brewer's Spent Grain by Neurospora Crassa. Bioresour. Technol. 99, 5427–5435. 10.1016/j.biortech.2007.11.010 PubMed DOI

Žnidaršič-Plazl P. (2021a). Let the Biocatalyst Flow. Acta Chim. Slov. 68, 1–16. 10.17344/acsi.2020.64 PubMed DOI

Žnidaršič-Plazl P. (2021b). Biocatalytic Process Intensification via Efficient Biocatalyst Immobilization, Miniaturization, and Process Integration. Curr. Opin. Green Sustain. Chem. 32, 100546. 10.1016/j.cogsc.2021.100546 DOI