Valorisation of brewers’ spent grain via alkaline pretreatment for protein concentrate and poly(3-hydroxybutyrate) production

Valorisation of brewers’ spent grain via alkaline pretreatment for protein concentrate and poly(3-hydroxybutyrate) production | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Valorisation of brewers’ spent grain via alkaline pretreatment for protein concentrate and poly(3-hydroxybutyrate) production Katiana Filippi, Chrysanthi Argeiti, Eleni Anna Kouvelioti, Eleni Stylianou, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8157766/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This work outlines an integrated biorefinery approach for the valorisation of brewer’s spent grain (BSG), targeting protein recovery and poly(3-hydroxybutyrate) (PHB) production. Initially, dextrins and proteins were extracted from BSG, followed by alkaline pretreatment of the residual solids. A Central Composite Design was employed to optimise lignin removal while minimising hemicellulose and glucan losses, with optimal conditions determined as 0.71% (w/v) NaOH at 71°C. After 30 min pretreatment at the optimal conditions, lignin, hemicellulose, and glucan removal reached 31.6%, 26.9%, and 12.5%, respectively, while enzymatic hydrolysis efficiency of glucan and hemicellulose reached 86.5% and 30.0%, respectively. The resulting hydrolysate served as a carbon source for PHB production by Paraburkholderia sacchari DSM 17165 under fed-batch conditions, yielding a dry cell weight of 86.6 g/L with 49.1% PHB (42.5 g/L), corresponding to 0.28 g/g yield and 1.23 g/(L·h) productivity. Based on the proposed biorefinery, 1 kg BSG could be used for the production of 76.3 g protein with 45.2% purity and 89.7 g PHB. The proposed process demonstrates a scalable and resource-efficient strategy for converting brewery residues into biodegradable polymers and protein-rich food additives, significantly advancing circular bioeconomy practices. biorefinery development brewery spent grain proteins alkaline pretreatment experimental design poly(3-hydroxybutyrate) Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8157766","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":619472907,"identity":"ffb39dc3-086a-4c14-960f-c3d6635c74ed","order_by":0,"name":"Katiana Filippi","email":"","orcid":"","institution":"Agricultural University of Athens","correspondingAuthor":false,"prefix":"","firstName":"Katiana","middleName":"","lastName":"Filippi","suffix":""},{"id":619472908,"identity":"7ff30ef5-81f5-4cb8-ade2-93736534c1e8","order_by":1,"name":"Chrysanthi Argeiti","email":"","orcid":"","institution":"Agricultural University of 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