{"paper_id":"40f854e8-3c4e-4eeb-be0b-fe270c10b09b","body_text":"Extraction and Characterization of Starch from Chlorella vulgaris Microalgae for 3D-Printable Bioplastic Materials | 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 Extraction and Characterization of Starch from Chlorella vulgaris Microalgae for 3D-Printable Bioplastic Materials Kokeb Hurruma Jiru, Hirpa Gelgele Lemu, Habte Jebessa Debella, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8347570/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 14 You are reading this latest preprint version Abstract Microalgae are increasingly recognized as a promising source of starch for bioplastic production, with Chlorella vulgaris emerging as a particularly strong candidate due to its notable starch accumulation capacity. This study examined the chemical composition, structure, thermal properties, and flow behavior of starch extracted from Chlorella vulgaris to evaluate its suitability for 3D-printable bioplastic production. A two-phase nitrogen management cultivation strategy resulted in a biomass productivity of 2310 mg/L and a starch content of approximately 46.39% of dry weight (463.92 ± 5.62 mg/g). Starch extraction was performed using ultrasonic homogenization in dimethyl sulphoxide (DMSO), followed by ethanol precipitation, yielding an 89.0% recovery rate (95.75 ± 0.313 g). Characterization of the extracted starch using attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) confirmed acceptable purity. A colorimetric assessment of amylose and amylopectin content revealed a composition of 20.74% amylose and 79.26% amylopectin, indicating favorable characteristics for retrogradation and viscoelasticity. Particle size analysis showed starch granules with an average diameter of 1.12~μm, which enhances flowability and printability. X-ray diffraction (XRD) analysis revealed broad peaks at 15.4º, 17.76º, 18.34º, 20.14º, and 23.14º, characteristic of an A-type semi-crystalline structure, along with an additional peak at 11.22º attributed to minor impurities. This semi-crystalline nature supports excellent extrudability and structural stability during 3D printing. Thermal and rheological analyses likewise confirmed properties favorable for melt extrusion, including clear shear-thinning behavior. Taken together, these findings position starch derived from Chlorella vulgaris as a promising alternative material for 3D-printable bioplastic applications. Future work should focus on optimizing filament formulations, refining printing parameters, and evaluating biodegradability to fully harness its industrial potential. Chlorella vulgaris starch ultrasonic homogenization bioplastic 3D printing microalgae Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 26 Feb, 2026 Reviews received at journal 10 Feb, 2026 Reviews received at journal 10 Feb, 2026 Reviews received at journal 08 Feb, 2026 Reviews received at journal 08 Feb, 2026 Reviewers agreed at journal 31 Jan, 2026 Reviewers agreed at journal 30 Jan, 2026 Reviewers agreed at journal 29 Jan, 2026 Reviewers agreed at journal 29 Jan, 2026 Reviewers agreed at journal 29 Jan, 2026 Reviewers invited by journal 29 Jan, 2026 Editor assigned by journal 25 Dec, 2025 Submission checks completed at journal 25 Dec, 2025 First submitted to journal 25 Dec, 2025 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. 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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-8347570\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":583479390,\"identity\":\"898781fe-cd52-4a62-9568-b5a3ce845392\",\"order_by\":0,\"name\":\"Kokeb Hurruma Jiru\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Jimma University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Kokeb\",\"middleName\":\"Hurruma\",\"lastName\":\"Jiru\",\"suffix\":\"\"},{\"id\":583479391,\"identity\":\"25e1cd99-d5fd-4394-aaf9-2d723569e6a6\",\"order_by\":1,\"name\":\"Hirpa Gelgele 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This study examined the chemical composition, structure, thermal properties, and flow behavior of starch extracted from Chlorella vulgaris to evaluate its suitability for 3D-printable bioplastic production. A two-phase nitrogen management cultivation strategy resulted in a biomass productivity of 2310 mg/L and a starch content of approximately 46.39% of dry weight (463.92 ± 5.62 mg/g). Starch extraction was performed using ultrasonic homogenization in dimethyl sulphoxide (DMSO), followed by ethanol precipitation, yielding an 89.0% recovery rate (95.75 ± 0.313 g). Characterization of the extracted starch using attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) confirmed acceptable purity. A colorimetric assessment of amylose and amylopectin content revealed a composition of 20.74% amylose and 79.26% amylopectin, indicating favorable characteristics for retrogradation and viscoelasticity. 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