{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,18]],"date-time":"2026-04-18T05:47:55Z","timestamp":1776491275878,"version":"3.51.2"},"reference-count":34,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2022,6,4]],"date-time":"2022-06-04T00:00:00Z","timestamp":1654300800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES (PIDDAC)","doi-asserted-by":"publisher","award":["LA\/P\/0045\/2020 (ALiCE)"],"award-info":[{"award-number":["LA\/P\/0045\/2020 (ALiCE)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES (PIDDAC)","doi-asserted-by":"publisher","award":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"],"award-info":[{"award-number":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES (PIDDAC)","doi-asserted-by":"publisher","award":["PTDC\/BTA-BTA\/31736\/2017"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/31736\/2017"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES (PIDDAC)","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-031736"],"award-info":[{"award-number":["POCI-01-0145-FEDER-031736"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES (PIDDAC)","doi-asserted-by":"publisher","award":["PTDC\/BTA-BTA\/2902\/2021"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/2902\/2021"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\/MCTES (PIDDAC)","doi-asserted-by":"publisher","award":["2020.05477.BD"],"award-info":[{"award-number":["2020.05477.BD"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"FEDER","award":["LA\/P\/0045\/2020 (ALiCE)"],"award-info":[{"award-number":["LA\/P\/0045\/2020 (ALiCE)"]}]},{"name":"FEDER","award":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"],"award-info":[{"award-number":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"]}]},{"name":"FEDER","award":["PTDC\/BTA-BTA\/31736\/2017"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/31736\/2017"]}]},{"name":"FEDER","award":["POCI-01-0145-FEDER-031736"],"award-info":[{"award-number":["POCI-01-0145-FEDER-031736"]}]},{"name":"FEDER","award":["PTDC\/BTA-BTA\/2902\/2021"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/2902\/2021"]}]},{"name":"FEDER","award":["2020.05477.BD"],"award-info":[{"award-number":["2020.05477.BD"]}]},{"DOI":"10.13039\/501100001871","name":"COMPETE2020\u2014Programa Operacional Competitividade e Internacionaliza\u00e7\u00e3o (POCI)","doi-asserted-by":"publisher","award":["LA\/P\/0045\/2020 (ALiCE)"],"award-info":[{"award-number":["LA\/P\/0045\/2020 (ALiCE)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"COMPETE2020\u2014Programa Operacional Competitividade e Internacionaliza\u00e7\u00e3o (POCI)","doi-asserted-by":"publisher","award":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"],"award-info":[{"award-number":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"COMPETE2020\u2014Programa Operacional Competitividade e Internacionaliza\u00e7\u00e3o (POCI)","doi-asserted-by":"publisher","award":["PTDC\/BTA-BTA\/31736\/2017"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/31736\/2017"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"COMPETE2020\u2014Programa Operacional Competitividade e Internacionaliza\u00e7\u00e3o (POCI)","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-031736"],"award-info":[{"award-number":["POCI-01-0145-FEDER-031736"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"COMPETE2020\u2014Programa Operacional Competitividade e Internacionaliza\u00e7\u00e3o (POCI)","doi-asserted-by":"publisher","award":["PTDC\/BTA-BTA\/2902\/2021"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/2902\/2021"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"COMPETE2020\u2014Programa Operacional Competitividade e Internacionaliza\u00e7\u00e3o (POCI)","doi-asserted-by":"publisher","award":["2020.05477.BD"],"award-info":[{"award-number":["2020.05477.BD"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["LA\/P\/0045\/2020 (ALiCE)"],"award-info":[{"award-number":["LA\/P\/0045\/2020 (ALiCE)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"],"award-info":[{"award-number":["UIDB\/00511\/2020-UIDP\/00511\/2020 (LEPABE)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["PTDC\/BTA-BTA\/31736\/2017"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/31736\/2017"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-031736"],"award-info":[{"award-number":["POCI-01-0145-FEDER-031736"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["PTDC\/BTA-BTA\/2902\/2021"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/2902\/2021"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["2020.05477.BD"],"award-info":[{"award-number":["2020.05477.BD"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Processes"],"abstract":"<jats:p>Microalgae have a lot of potential as a source of several compounds of interest to various industries. However, developing a sustainable and efficient harvesting process on a large scale is still a major challenge. This is particularly a problem when the production of low-value products is intended. Chemical flocculation, followed by sedimentation, is seen as an alternative method to improve the energetic and economic balance of the harvesting step. In this study, inorganic (aluminum sulfate, ferric sulfate, ferric chloride) and organic (Zetag 8185, chitosan, Tanfloc SG) flocculants were tested to harvest Chlorella vulgaris in batch mode. Preliminary assays were conducted to determine the minimum dosages of each flocculant that generates primary flocs at different pH. Except for chitosan, the organic flocculants required small dosages to initiate floc formation. Additional studies were performed for the flocculants with a better performance in the preliminary assays. Zetag 8185 had the best results, reaching 98.8% and 97.9% efficiencies with dosages of 50 and 100 mg L\u22121, respectively. Lastly, a 24 full factorial design experiment was performed to determine the effects of the flocculant dosage, settling time, and mixing time on the Zetag 8185 harvesting efficiency. The harvesting efficiency of C. vulgaris was optimal at a dosage of 100 mg L\u22121 and 3 min of rapid mixing.<\/jats:p>","DOI":"10.3390\/pr10061124","type":"journal-article","created":{"date-parts":[[2022,6,4]],"date-time":"2022-06-04T09:42:32Z","timestamp":1654335752000},"page":"1124","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Optimization of Microalgal Harvesting with Inorganic and Organic Flocculants Using Factorial Design of Experiments"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3703-1313","authenticated-orcid":false,"given":"Cl\u00e1udia A.","family":"Machado","sequence":"first","affiliation":[{"name":"LEPABE\u2014Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"AliCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"given":"Ana F.","family":"Esteves","sequence":"additional","affiliation":[{"name":"LEPABE\u2014Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"AliCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2738-5102","authenticated-orcid":false,"given":"Jos\u00e9 C. M.","family":"Pires","sequence":"additional","affiliation":[{"name":"LEPABE\u2014Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"},{"name":"AliCE\u2014Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1489","DOI":"10.1016\/j.rser.2014.09.037","article-title":"Harvesting techniques applied to microalgae: A review","volume":"41","author":"Barros","year":"2015","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"791","DOI":"10.1007\/s00449-022-02711-1","article-title":"Lab-scale photobioreactor systems: Principles, applications, and scalability","volume":"45","author":"Benner","year":"2022","journal-title":"Bioprocess Biosyst. Eng."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Shekh, A., Schenk, P., and Sarada, R. (2021). Microalgal Biorefineries: Key Processes and Main Challenges. Microalgal Biotechnology: Recent Advances, Market Potencial, and Sustainability, Royal Society of Chemistry.","DOI":"10.1039\/9781839162473"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1080\/26388081.2020.1715256","article-title":"Chlorella vulgaris: A perspective on its potential for combining high biomass with high value bioproducts","volume":"1","author":"Ru","year":"2020","journal-title":"Appl. Phycol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1002\/bit.10669","article-title":"Kinetic modeling of the light-dependent photosynthetic activity of the green microalga Chlorella vulgaris","volume":"83","author":"Yun","year":"2003","journal-title":"Biotechnol. Bioeng."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Zheng, M.M., Ji, X.W., He, Y.J., Li, Z.F., Wang, M.Z., Chen, B.L., and Huang, J. (2020). Simultaneous fixation of carbon dioxide and purification of undiluted swine slurry by culturing Chlorella vulgaris MBFJNU-1. Algal Res., 47.","DOI":"10.1016\/j.algal.2020.101866"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1186\/s12934-018-0879-x","article-title":"The promising future of microalgae: Current status, challenges, and optimization of a sustainable and renewable industry for biofuels, feed, and other products","volume":"17","author":"Khan","year":"2018","journal-title":"Microb. Cell Factories"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Alam, M., and Wang, Z. (2019). Harvesting of microalgae for biomass production. Microalgae Biotechnology for Development of Biofuel and Wastewater Treatment, Springer.","DOI":"10.1007\/978-981-13-2264-8"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Branyikova, I., Prochazkova, G., Potocar, T., Jezkova, Z., and Branyik, T. (2018). Harvesting of microalgae by flocculation. Fermentation, 4.","DOI":"10.3390\/fermentation4040093"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"126222","DOI":"10.1016\/j.biortech.2021.126222","article-title":"Nannochloropsis oceanica harvested using electrocoagulation with alternative electrodes\u2014An innovative approach on potential biomass applications","volume":"344","author":"Figueiredo","year":"2022","journal-title":"Bioresour. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1016\/j.algal.2016.03.037","article-title":"Settling velocity distribution of microalgal biomass from urban wastewater treatment high rate algal ponds","volume":"16","author":"Gutierrez","year":"2016","journal-title":"Algal Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.swaqe.2014.12.008","article-title":"Characterisation of algogenic organic matter during an algal bloom and its implications for trihalomethane formation","volume":"6","author":"Gough","year":"2015","journal-title":"Sustain. Water Qual. Ecol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1803","DOI":"10.1080\/10643389.2019.1586057","article-title":"Algogenic organic matter derived DBPs: Precursor characterization, formation, and future perspectives\u2014A review","volume":"49","author":"Hua","year":"2019","journal-title":"Crit. Rev. Environ. Sci. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1828","DOI":"10.1039\/D0EW00176G","article-title":"Production of microalgal external organic matter in a Chlorella-dominated culture: Influence of temperature and stress factors","volume":"6","author":"Seco","year":"2020","journal-title":"Environ. Sci. Water Res. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/j.biombioe.2016.02.015","article-title":"Flocculation of Nannochloropsis oculata using a tannin-based polymer: Bench scale optimization and pilot scale reproducibility","volume":"87","author":"Roselet","year":"2016","journal-title":"Biomass Bioenergy"},{"key":"ref_16","unstructured":"Davis, M.L. (2010). Coagulation and Flocculation. Water and Wastewater Engineering: Design Principles and Practice, McGraw-Hill Education."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"140875","DOI":"10.1016\/j.scitotenv.2020.140875","article-title":"Chemical modification of tannins from Acacia mearnsii to produce formaldehyde free flocculant","volume":"745","author":"Machado","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1016\/j.biortech.2013.08.080","article-title":"Coagulation\u2013flocculation of marine Chlorella sp. for biodiesel production","volume":"147","author":"Sanyano","year":"2013","journal-title":"Bioresour. Technol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"100099","DOI":"10.1016\/j.clet.2021.100099","article-title":"Efficacy of two natural tannins-based polymers in contrast to aluminum sulfate for drinking water production","volume":"3","author":"Schmitt","year":"2021","journal-title":"Clean. Eng. Technol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1186\/s13068-018-1183-z","article-title":"Microalgae Chlorella vulgaris biomass harvesting by natural flocculant: Effects on biomass sedimentation, spent medium recycling and lipid extraction","volume":"11","author":"Zhu","year":"2018","journal-title":"Biotechnol. Biofuels"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1016\/j.biortech.2017.05.021","article-title":"Acidified-flocculation process for harvesting of microalgae: Coagulant reutilization and metal-free-microalgae recovery","volume":"239","author":"Kim","year":"2017","journal-title":"Bioresour. Technol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"121267","DOI":"10.1016\/j.jclepro.2020.121267","article-title":"State of the art and sustainability of natural coagulants in water and wastewater treatment","volume":"262","author":"Ang","year":"2020","journal-title":"J. Clean. Prod."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"149395","DOI":"10.1016\/j.scitotenv.2021.149395","article-title":"Metal-based flocculation to harvest microalgae: A look beyond separation efficiency","volume":"799","author":"Rossi","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2767","DOI":"10.1007\/s10811-016-0837-0","article-title":"Toxicity and bioaccumulation of iron in soil microalgae","volume":"28","author":"Subramaniyam","year":"2016","journal-title":"J. Appl. Phycol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1111\/bpa.12333","article-title":"Understanding aspects of Aluminum exposure in a lzheimer\u2019s disease development","volume":"26","author":"Kandimalla","year":"2016","journal-title":"Brain Pathol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1627","DOI":"10.3233\/JAD-191140","article-title":"Aluminum and amyloid-\u03b2 in familial Alzheimer\u2019s disease","volume":"73","author":"Mold","year":"2020","journal-title":"J. Alzheimer\u2019s Dis."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4363","DOI":"10.1021\/acs.iecr.5b04703","article-title":"Recent advancement of coagulation\u2013flocculation and its application in wastewater treatment","volume":"55","author":"Teh","year":"2016","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2317","DOI":"10.1007\/s10811-018-1429-y","article-title":"Harvesting Neochloris oleoabundans using commercial organic flocculants","volume":"30","author":"Kirnev","year":"2018","journal-title":"J. Appl. Phycol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1621","DOI":"10.1007\/s10811-021-02393-4","article-title":"Optimization of Chlorella biomass harvesting by flocculation and its potential for biofuel production","volume":"33","author":"Japar","year":"2021","journal-title":"J. Appl. Phycol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1023\/A:1022137023257","article-title":"Flocculation of algae using chitosan","volume":"14","author":"Divakaran","year":"2002","journal-title":"J. Appl. Phycol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1080\/15435075.2016.1261707","article-title":"Effect of pH and alum dosage on the efficiency of microalgae harvesting via flocculation technique","volume":"14","author":"Gani","year":"2017","journal-title":"Int. J. Green Energy"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"126404","DOI":"10.1016\/j.biortech.2021.126404","article-title":"Recent progress in flocculation, dewatering, and drying technologies for microalgae utilization: Scalable and low-cost harvesting process development","volume":"344","author":"Min","year":"2022","journal-title":"Bioresour. Technol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1016\/j.biortech.2012.11.068","article-title":"Chitosan flocculation to aid the harvesting of the microalga Chlorella sorokiniana","volume":"129","author":"Xu","year":"2013","journal-title":"Bioresour. Technol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"536","DOI":"10.1111\/ppl.13409","article-title":"The use of natural organic flocculants for harvesting microalgae grown in municipal wastewater at different culture densities","volume":"173","author":"Niemi","year":"2021","journal-title":"Physiol. Plant."}],"container-title":["Processes"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2227-9717\/10\/6\/1124\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:24:29Z","timestamp":1760138669000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2227-9717\/10\/6\/1124"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,6,4]]},"references-count":34,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2022,6]]}},"alternative-id":["pr10061124"],"URL":"https:\/\/doi.org\/10.3390\/pr10061124","relation":{},"ISSN":["2227-9717"],"issn-type":[{"value":"2227-9717","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,6,4]]}}}