Fermentation-Based Oxalic Acid Production for Sustainable Gallium Recovery from Electronic Waste

Fermentation-Based Oxalic Acid Production for Sustainable Gallium Recovery from Electronic Waste | 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 Fermentation-Based Oxalic Acid Production for Sustainable Gallium Recovery from Electronic Waste Aylin Nur Erkmen, Roland Ulber, Thomas Juestel, Mirjam Altendorfner This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8182360/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 Oxalic acid (OA) is a versatile reagent ubiquitously used in pharmaceutical, agricultural, and chemical industries. Aligning with the European Union's 2050 circular economy agenda, its potential application in ore processing, and particularly metal extraction from electronic waste (e-waste) has garnered significant attention. Gallium (Ga) is a technologically strategic metal at high supply risk, driven by high demand from the electronics industry and limited primary production. Oxalic acid (OA), known for superior dissolution and complexation, is a highly selective metal recovery reagent that has been reported to outperform conventional reagents in gallium (Ga) recovery. However, current petrochemical OA production opposes global sustainability goals. To address this, submerged fermentation using filamentous fungi, notably Aspergillus niger offers a promising OA production route, that goes hand-in-hand with selective metal recovery. This study investigates OA generation through submerged fermentation, beginning with shake-flask experiments that identified ATCC1015 as the suitable candidate, achieving 71 \((\pm)\) 27.73 mM OA in 5 days, which later was enhanced to 90.37 \((\pm)\) 5.8 mM through intermittent pH adjustment above 4. Glucose was reported as the optimal carbon source, yielding Y\textsubscript{P/S} \((\approx)\) 0.4 (g/g). Scale-up in a 10 L bioreactor using fed-batch fermentation with pulsed feeding and pH control achieved 260.1 \((\pm)\) 4.8 mM OA over 14 days. Co-production of gluconic acid and acidogenesis inhibition posed a challenge in attaining higher product yields. Collectively, these findings establish fed-batch fermentation with robust pH control as a viable strategy for sustainable OA production, enabling targeted Ga recovery from waste streams. oxalic acid ATCC1015 submerged fermentation fed-batch particle morphology bioleaching Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementary20250412.pdf 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-8182360","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":557246401,"identity":"13d0c3d2-1c94-4942-b545-d5586867a6ff","order_by":0,"name":"Aylin Nur 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Waste","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"oxalic acid, ATCC1015, submerged fermentation, fed-batch, particle, morphology, bioleaching","lastPublishedDoi":"10.21203/rs.3.rs-8182360/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8182360/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eOxalic acid (OA) is a versatile reagent ubiquitously used in pharmaceutical, agricultural, and chemical industries. Aligning with the European Union's 2050 circular economy agenda, its potential application in ore processing, and particularly metal extraction from electronic waste (e-waste) has garnered significant attention. Gallium (Ga) is a technologically strategic metal at high supply risk, driven by high demand from the electronics industry and limited primary production. Oxalic acid (OA), known for superior dissolution and complexation, is a highly selective metal recovery reagent that has been reported to outperform conventional reagents in gallium (Ga) recovery. However, current petrochemical OA production opposes global sustainability goals. To address this, submerged fermentation using filamentous fungi, notably \u003cem\u003eAspergillus niger\u003c/em\u003e offers a promising OA production route, that goes hand-in-hand with selective metal recovery. This study investigates OA generation through submerged fermentation, beginning with shake-flask experiments that identified \u003cem\u003eATCC1015\u003c/em\u003e as the suitable candidate, achieving 71 \\((\\pm)\\) 27.73 mM OA in 5 days, which later was enhanced to 90.37 \\((\\pm)\\) 5.8 mM through intermittent pH adjustment above 4. Glucose was reported as the optimal carbon source, yielding Y\\textsubscript{P/S} \\((\\approx)\\) 0.4 (g/g). Scale-up in a 10 L bioreactor using fed-batch fermentation with pulsed feeding and pH control achieved 260.1 \\((\\pm)\\) 4.8 mM OA over 14 days. Co-production of gluconic acid and acidogenesis inhibition posed a challenge in attaining higher product yields. Collectively, these findings establish fed-batch fermentation with robust pH control as a viable strategy for sustainable OA production, enabling targeted Ga recovery from waste streams.\u003c/p\u003e","manuscriptTitle":"Fermentation-Based Oxalic Acid Production for Sustainable Gallium Recovery from Electronic Waste","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-10 09:17:22","doi":"10.21203/rs.3.rs-8182360/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1c0c2ffd-cfd1-4df2-945b-043c5934f953","owner":[],"postedDate":"December 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-27T04:08:15+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-10 09:17:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8182360","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8182360","identity":"rs-8182360","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}