{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T07:00:20Z","timestamp":1785308420322,"version":"3.55.0"},"reference-count":63,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T00:00:00Z","timestamp":1785283200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"<jats:sec>\n                    <jats:title>Inroduction<\/jats:title>\n                    <jats:p>Biosurfactants have become a topic of interest in recent years as low-cost and environmentally friendly agents. Their potential to improve oil recovery has been addressed previously, yet there are some concerns about their performance under reservoir extreme conditions. This study aims to assess Sophorolipids, an anionic biosurfactant, to enhance oil recovery in one of the Omani tight carbonate reservoirs characterized by high temperature and high salinity conditions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This was conducted by examining its effect on interfacial tension and wettability of carbonate at different concentrations, followed by core flooding experiments and ending by observing the stability of the biosurfactant at reservoir conditions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Results showed that the biosurfactant solution at the determined critical micelle concentration (CMC) of 1% was able to decrease the surface tension (ST) from 65.3 \u00b1 0.2 mN\/m to 32.46 \u00b1 0.01 mN\/m, and the interfacial tension (IFT) of oil\/ water from 20.45 \u00b1 0.3 mN\/m to 2.02 \u00b1 0.22 mN\/m. Similarly, the dynamic interfacial tension showed a reduction by two orders of magnitude, i.e., from 20.63 to 0.454 mN\/m. Contact angle (CA) revealed that the tested solution has a good potential to modify rock wettability from oil-wet (120\u00b0) to more intermediate-wet (70.6\u00b0), which was in line with Amott test results. In addition, core flooding resulted in an additional recovery fall of 4.6 to 8.9% of the oil volume initially in place. It was found that incremental oil recovery was mainly due to wettability alteration toward intermediate wet coupled with IFT reduction. Moreover, the anionic biosurfactant exhibited good thermal stability after 6 months of aging at 70 \u00b0C, as indicated by stable surface\/interfacial tension, contact angle, and recovery factors. Results of this study support the potential of this biosurfactant for EOR applications in carbonate reservoirs.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fmicb.2026.1895018","type":"journal-article","created":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T06:02:54Z","timestamp":1785304974000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Experimental investigation of sophorolipids injection for enhanced oil recovery in carbonate reservoir"],"prefix":"10.3389","volume":"17","author":[{"given":"Hala","family":"Al-Hemeidi","sequence":"first","affiliation":[{"name":"Department of Petroleum and Chemical Engineering, College of Engineering, Sultan Qaboos University","place":["Muscat, Oman"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sami","family":"Al-Khamisi","sequence":"additional","affiliation":[{"name":"Oil and Gas Research Centre, Sultan Qaboos University","place":["Muscat, Oman"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yahya","family":"Al-Wahaibi","sequence":"additional","affiliation":[{"name":"A\u2019Sharqiyah University","place":["Ibra, Oman"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saif","family":"Al-Bahry","sequence":"additional","affiliation":[{"name":"Department of Biology, College of Science, Sultan Qaboos University","place":["Muscat, Oman"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sanket J.","family":"Joshi","sequence":"additional","affiliation":[{"name":"Oil and Gas Research Centre, Sultan Qaboos University","place":["Muscat, Oman"]},{"name":"Amity Institute of Microbial Technology, Amity University Rajasthan","place":["Jaipur, India"]},{"name":"Amity Microbial Culture Centre, Amity University Rajasthan","place":["Jaipur, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,7,29]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"17292","DOI":"10.1021\/acs.energyfuels.5c03526","article-title":"Adsorption and foamability of the bio-PLs surfactant for improving oil recovery: experimental insights from carbonate cores","volume":"39","author":"Abdulhadi","year":"2025","journal-title":"Energy Fuel"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1016\/j.petrol.2019.106383","article-title":"Stability test of biosurfactant produced by Bacillus licheniformis DS1 using experimental design and its application for MEOR","volume":"183","author":"Adhitya","year":"2019","journal-title":"J. Pet. Sci. Eng."},{"key":"ref3","volume-title":"Mechanisms of Surfactant Enhanced Oil Recovery in Oil-Wet Fractured Carbonate Reservoirs","author":"Adibhatla","year":"2006"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"141","DOI":"10.1016\/j.ibiod.2012.01.006","article-title":"Biosurfactant production by Bacillus subtilis B20 using date molasses and its possible application in enhanced oil recovery","volume":"81","author":"Al-Bahry","year":"2013","journal-title":"Int. Biodeterior. Biodegrad."},{"key":"ref5","doi-asserted-by":"publisher","first-page":"119432","DOI":"10.1016\/j.fuel.2020.119432","article-title":"Application of a new bio-ASP for enhancement of oil recovery: mechanism study and core displacement test","volume":"287","author":"Al-Ghailani","year":"2020","journal-title":"Fuel"},{"key":"ref6","first-page":"4933","article-title":"Microbial biomass for improving sweep efficiency in fractured carbonate reservoir using date molasses as renewable feed substrate proceedings - SPE annual technical conference and exhibition","author":"Al-Hattali","year":"2012"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"103724","DOI":"10.1016\/j.jprocont.2026.103724","article-title":"A hybrid causal-inference and neuro-fuzzy framework for advanced process monitoring","volume":"162","author":"Ali","year":"2026","journal-title":"J. Process Control"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"106361","DOI":"10.1016\/j.conengprac.2025.106361","article-title":"Intelligent machine learning-based multi-model fusion monitoring: application to industrial physio-chemical systems","volume":"162","author":"Ali","year":"","journal-title":"Control. Eng. Pract."},{"key":"ref9","doi-asserted-by":"publisher","first-page":"22465","DOI":"10.1021\/acs.iecr.5c02759","article-title":"Hybrid fusion paradigm in advanced process monitoring: a panoramic review and future perspectives","volume":"64","author":"Ali","year":"","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref10","doi-asserted-by":"publisher","first-page":"100709","DOI":"10.1016\/j.jii.2024.100709","article-title":"Advance industrial monitoring of physio-chemical processes using novel integrated machine learning approach","volume":"42","author":"Ali","year":"2024","journal-title":"J. Ind. Inf. Integr."},{"key":"ref11","doi-asserted-by":"publisher","first-page":"110407","DOI":"10.1016\/j.petrol.2022.110407","article-title":"Front-end engineering practice of in-situ MEOR applications","volume":"216","author":"Alkan","year":"2022","journal-title":"J. Pet. Sci. Eng."},{"key":"ref12","doi-asserted-by":"publisher","first-page":"672","DOI":"10.2118\/129228-pa","article-title":"Optimization and partial characterization of biosurfactants produced by Bacillus species and their potential for ex-situ enhanced oil recovery","volume":"16","author":"Al-Sulaimani","year":"2011","journal-title":"SPE J."},{"key":"ref13","doi-asserted-by":"publisher","first-page":"1529","DOI":"10.3390\/en3091529","article-title":"Enhanced oil recovery: an update review","volume":"3","author":"Alvarado","year":"2010","journal-title":"Energies"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"100","DOI":"10.1007\/s12182-015-0067-0","article-title":"Injection of biosurfactant and chemical surfactant following hot water injection to enhance heavy oil recovery","volume":"13","author":"Al-Wahaibi","year":"2016","journal-title":"Pet. Sci."},{"key":"ref15","doi-asserted-by":"publisher","first-page":"1125","DOI":"10.2118\/13932-pa","article-title":"Wettability literature survey-part 1: rock\/oil\/brine interactions and the effects of core handling on wettability","volume":"38","author":"Anderson","year":"1986","journal-title":"JPT, J. Pet. Technol."},{"key":"ref16","doi-asserted-by":"publisher","first-page":"1915","DOI":"10.2118\/231828-pa","article-title":"Machine learning and kinetic insights into biomass and biosurfactant production for enhanced oil recovery applications","volume":"31","author":"Awadh","year":"2026","journal-title":"SPE J."},{"key":"ref17","doi-asserted-by":"publisher","first-page":"115768","DOI":"10.1016\/j.rser.2025.115768","article-title":"From hydrocarbon to low-carbon hydrogen: energy and economic challenges facing the Middle East and North Africa region","volume":"217","author":"Barnet","year":"2025","journal-title":"Renew. Sust. Energ. Rev."},{"key":"ref18","doi-asserted-by":"publisher","first-page":"22730","DOI":"10.1038\/s41598-025-05707-5","article-title":"Experimental and theoretical investigation of zwitterionic surfactant adsorption on calcite for enhanced oil recovery","volume":"15","author":"Bazyari","year":"2025","journal-title":"Sci. Rep."},{"key":"ref19","doi-asserted-by":"publisher","first-page":"484","DOI":"10.3390\/life16030484","article-title":"Microbial biosurfactants: a bridge from aquatic environments to subsurface oil recovery: mechanisms, challenges, prospects","volume":"16","author":"Chang","year":"2026","journal-title":"Life"},{"key":"ref20","doi-asserted-by":"publisher","first-page":"38196","DOI":"10.1039\/c8ra08423h","article-title":"Investigations on the driving forces of the fluorocarbon surfactant-assisted spontaneous imbibition using thermogravimetric analysis (TGA)","volume":"8","author":"Chen","year":"2018","journal-title":"RSC Adv."},{"key":"ref21","doi-asserted-by":"publisher","first-page":"31","DOI":"10.1021\/acs.energyfuels.9b03409","article-title":"A review on wettability alteration in carbonate rocks: wettability modifiers","volume":"34","author":"Deng","year":"2019","journal-title":"Energy Fuel"},{"key":"ref9001","doi-asserted-by":"publisher","first-page":"47","DOI":"10.1128\/mmbr.61.1.47-64.1997","article-title":"Microbial production of surfactants and their commercial potential","volume":"61","author":"Desai","year":"1997","journal-title":"Microbiol Mol Biol Rev"},{"key":"ref22","doi-asserted-by":"publisher","first-page":"1324","DOI":"10.3389\/fmicb.2015.01324","article-title":"Sophorolipids production by Candida bombicola ATCC 22214 and its potential application in microbial enhanced oil recovery","volume":"6","author":"Elshafie","year":"2015","journal-title":"Front. Microbiol."},{"key":"ref23","year":"2016"},{"key":"ref24","doi-asserted-by":"publisher","first-page":"126198","DOI":"10.1016\/j.molliq.2024.126198","article-title":"Modification and mechanistic study of fluid\/fluid and carbonate rock\/fluid interfaces using a glycolipid biosurfactant from an indigenous strain of Gordonia terrae for MEOR applications","volume":"414","author":"Ghorbani","year":"2024","journal-title":"J. Mol. Liq."},{"key":"ref25","doi-asserted-by":"publisher","first-page":"126757","DOI":"10.1016\/j.fuel.2022.126757","article-title":"Investigating the potential of microbial enhanced oil recovery in carbonate reservoirs using Bacillus persicus","volume":"334","author":"Haddad","year":"2023","journal-title":"Fuel"},{"key":"ref9002","doi-asserted-by":"publisher","first-page":"422","DOI":"10.1016\/j.colsurfa.2016.11.010","article-title":"The synergic effects of anionic and cationic chemical surfactants, and bacterial solution on wettability alteration of carbonate rock: An experimental investigation","volume":"513","author":"Hajibagheri","year":"2017","journal-title":"Colloids and Surfaces A: Physicochemical and Engineering Aspects"},{"key":"ref26","doi-asserted-by":"publisher","first-page":"825","DOI":"10.1007\/s43153-021-00208-0","article-title":"Effects of rhamnolipid bio-surfactant and sodium dodecylbenzene sulfonate (SDBS) surfactant on enhanced oil recovery from carbonate reservoirs","volume":"39","author":"Imanivarnosfaderani","year":"2022","journal-title":"Braz. J. Chem. Eng."},{"key":"ref27","doi-asserted-by":"publisher","first-page":"1539","DOI":"10.1007\/s13202-019-00775-6","article-title":"Microorganisms\u2019 effect on the wettability of carbonate oil-wet surfaces: implications for MEOR, smart water injection and reservoir souring mitigation strategies","volume":"10","author":"Jahanbani Veshareh","year":"2020","journal-title":"J. Pet. Explor. Prod. Technol."},{"key":"ref28","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.colsurfa.2012.06.007","article-title":"Wettability alteration of carbonate rocks by surfactants: a mechanistic study","volume":"410","author":"Jarrahian","year":"2012","journal-title":"Colloids Surf. A Physicochem. Eng. Aspects"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"2064","DOI":"10.1080\/10916466.2022.2036190","article-title":"Glycolipid biosurfactant-silica nanoparticles based green application for enhancement of oil recovery","volume":"40","author":"Joshi","year":"2022","journal-title":"Pet. Sci. Technol."},{"key":"ref30","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3389\/fmicb.2016.01853","article-title":"Production, characterization, and application of Bacillus licheniformis W16 biosurfactant in enhancing oil recovery","volume":"7","author":"Joshi","year":"2016","journal-title":"Front. Microbiol."},{"key":"ref31","doi-asserted-by":"publisher","first-page":"15401","DOI":"10.1038\/s41598-024-65728-4","article-title":"Appropriate characterization of reservoir properties and investigation of their effect on microbial enhanced oil recovery through simulated laboratory studies","volume":"14","author":"Kapse","year":"2024","journal-title":"Sci. Rep."},{"key":"ref32","doi-asserted-by":"publisher","first-page":"1183","DOI":"10.1080\/07388551.2023.2270578","article-title":"Microbial enhanced oil recovery (MEOR): recent development and future perspectives","volume":"44","author":"Ke","year":"2024","journal-title":"Crit. Rev. Biotechnol."},{"key":"ref33","doi-asserted-by":"publisher","first-page":"257","DOI":"10.22059\/jchpe.2021.322527.1349","article-title":"Using a new mixture of reagents for effective inhibition of corrosion and salt precipitation in the petroleum industry","volume":"55","author":"Khormali","year":"2021","journal-title":"J. Chem. Pet. Eng."},{"key":"ref9003","doi-asserted-by":"publisher","first-page":"275","DOI":"10.1016\/j.petrol.2006.03.011","article-title":"Microbial improved oil recovery\u2014bacterial induced wettability and interfacial tension effects on oil production","volume":"52","author":"Kowalewski","year":"2006","journal-title":"Journal of Petroleum science and Engineering"},{"key":"ref9004","doi-asserted-by":"publisher","first-page":"133","DOI":"10.1016\/j.ibiod.2012.09.012","article-title":"Prospects for using native and recombinant rhamnolipid producers for microbially enhanced oil recovery","volume":"81","author":"Kryachko","year":"2013","journal-title":"International Biodeterioration & Biodegradation"},{"key":"ref34","doi-asserted-by":"publisher","first-page":"539","DOI":"10.1134\/s0965544123030210","article-title":"Increasing the efficiency of demulsification treatment in petroleum industry using a multicomponent demulsifier package","volume":"63","author":"Khormali","year":"2023","journal-title":"Pet. Chem."},{"key":"ref35","doi-asserted-by":"publisher","first-page":"2706","DOI":"10.3390\/microorganisms13122706","article-title":"Mineral-targeted microbial enhanced oil recovery","volume":"13","author":"Li","year":"2025","journal-title":"Microorganisms"},{"key":"ref36","author":"Liu","year":"2011"},{"key":"ref37","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1080\/07388551.2026.2619529","article-title":"Microbial enhanced oil recovery in China: progress and prospects","author":"Liu","year":"2026","journal-title":"Crit. Rev. Biotechnol."},{"key":"ref38","doi-asserted-by":"publisher","first-page":"2071","DOI":"10.2118\/82071-ms","article-title":"Carbonate reservoir characterization","volume":"55","author":"Lucia","year":"2003","journal-title":"J. Pet. Technol."},{"key":"ref39","doi-asserted-by":"publisher","first-page":"1551","DOI":"10.1007\/s13202-019-00789-0","article-title":"Experimental study of the performances of commercial surfactants in reducing interfacial tension and wettability alteration in the process of chemical water injection into carbonate reservoirs","volume":"10","author":"Najimi","year":"2020","journal-title":"J. Pet. Explor. Prod. Technol."},{"key":"ref40","doi-asserted-by":"publisher","first-page":"5979","DOI":"10.1007\/s00253-013-4863-4","article-title":"Core flooding tests to investigate the effects of IFT reduction and wettability alteration on oil recovery during MEOR process in an Iranian oil reservoir","volume":"97","author":"Rabiei","year":"2013","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref41","author":"Rapier","year":"2020"},{"key":"ref42","doi-asserted-by":"publisher","first-page":"729","DOI":"10.1007\/s11274-006-9278-2","article-title":"Enhancement of stability of biosurfactant produced by Candida lipolytica using industrial residue as substrate","volume":"23","author":"Rufino","year":"2007","journal-title":"World J. Microbiol. Biotechnol."},{"key":"ref43","doi-asserted-by":"publisher","first-page":"159","DOI":"10.1016\/j.rser.2017.02.045","article-title":"Microbial enhanced oil recovery, a critical review on worldwide implemented field trials in different countries","volume":"74","author":"Safdel","year":"2017","journal-title":"Renew. Sust. Energ. Rev."},{"key":"ref44","doi-asserted-by":"publisher","first-page":"68","DOI":"10.1007\/s00284-006-0412-z","article-title":"Co-utilization of canola oil and glucose on the production of a surfactant by Candida lipolytica","volume":"54","author":"Sarubbo","year":"2007","journal-title":"Curr. Microbiol."},{"key":"ref45","year":"2007"},{"key":"ref46","volume-title":"Handbook of Petroleum Exploration and Production","author":"Sch\u00f6n","year":"2011"},{"key":"ref47","doi-asserted-by":"publisher","first-page":"714","DOI":"10.1016\/j.pecs.2008.05.001","article-title":"Biotechnology in petroleum recovery: the microbial EOR","volume":"34","author":"Sen","year":"2008","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref48","doi-asserted-by":"publisher","first-page":"15286","DOI":"10.1080\/15567036.2020.1810826","article-title":"Comparison of produced biosurfactants performance in in-situ and ex-situ MEOR: micromodel study","volume":"46","author":"Shabani","year":"2024","journal-title":"Energy Sources A"},{"key":"ref49","doi-asserted-by":"publisher","first-page":"301","DOI":"10.3390\/molecules29020301","article-title":"New trends in biosurfactants: from renewable origin to green enhanced oil recovery applications","volume":"29","author":"Shaikhah","year":"2024","journal-title":"Molecules"},{"key":"ref50","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1016\/B978-0-12-386545-8.00012-9","volume-title":"Enhanced Oil Recovery Field Case Studies","author":"Sheng","year":"2013"},{"key":"ref51","doi-asserted-by":"publisher","first-page":"62189","DOI":"10.1021\/acsomega.5c09824","article-title":"Sophorolipid-based biosurfactant application for carbonated water flooding: an experimental approach for enhanced oil recovery","volume":"10","author":"Singh","year":"2025","journal-title":"ACS Omega"},{"key":"ref52","doi-asserted-by":"publisher","first-page":"S15","DOI":"10.1134\/s0026261724609631","article-title":"Microbiological characteristics of sapropel and the possibility of its application for enhanced oil recovery from carbonate reservoirs","volume":"93","author":"Sokolova","year":"2024","journal-title":"Microbiology"},{"key":"ref53","doi-asserted-by":"publisher","first-page":"113","DOI":"10.3390\/chemengineering9050113","article-title":"Petroleum emulsion stability and separation strategies: a comprehensive review","volume":"9","author":"Soroush","year":"2025","journal-title":"ChemEngineering"},{"key":"ref54","author":"Souayeh","year":"2014"},{"key":"ref55","author":"Thyne","year":"2013"},{"key":"ref56","author":"Ukwungwu","year":"2017"},{"key":"ref57","doi-asserted-by":"publisher","first-page":"26","DOI":"10.17794\/rgn.2026.2.6","article-title":"Effect of calcium and magnesium ions on a crude oil-brine-carbonate rock system for enhanced oil recovery by sophorolipid solution","volume":"41","author":"Widiyaningsih","year":"2026","journal-title":"Rud.-Geol. Naft. Zbor."},{"key":"ref58","doi-asserted-by":"publisher","first-page":"147","DOI":"10.1016\/S0920-4105(97)00015-6","article-title":"The potential of Bacillus licheniformis strains for in situ enhanced oil recovery","volume":"18","author":"Yakimov","year":"1997","journal-title":"J. Pet. Sci. Eng."},{"key":"ref59","doi-asserted-by":"publisher","first-page":"6854","DOI":"10.3390\/en16196854","article-title":"Long-term pore-scale experiments on MEOR by surfactant-producing microorganisms reveal the altering dominant mechanisms of oil recovery","volume":"16","author":"Yu","year":"2023","journal-title":"Energies"}],"container-title":["Frontiers in Microbiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2026.1895018\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T06:02:56Z","timestamp":1785304976000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2026.1895018\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,29]]},"references-count":63,"alternative-id":["10.3389\/fmicb.2026.1895018"],"URL":"https:\/\/doi.org\/10.3389\/fmicb.2026.1895018","relation":{},"ISSN":["1664-302X"],"issn-type":[{"value":"1664-302X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,29]]},"article-number":"1895018"}}