{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T10:39:32Z","timestamp":1789641572078,"version":"4.0.0"},"reference-count":38,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,5,16]],"date-time":"2025-05-16T00:00:00Z","timestamp":1747353600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Fulbright","award":["PS00345108"],"award-info":[{"award-number":["PS00345108"]}]},{"name":"Fulbright","award":["PMD522071138426"],"award-info":[{"award-number":["PMD522071138426"]}]},{"name":"Fulbright","award":["NSF-OIA-2119809"],"award-info":[{"award-number":["NSF-OIA-2119809"]}]},{"name":"National Research Foundation (NRF)","award":["PS00345108"],"award-info":[{"award-number":["PS00345108"]}]},{"name":"National Research Foundation (NRF)","award":["PMD522071138426"],"award-info":[{"award-number":["PMD522071138426"]}]},{"name":"National Research Foundation (NRF)","award":["NSF-OIA-2119809"],"award-info":[{"award-number":["NSF-OIA-2119809"]}]},{"name":"National Science Foundation","award":["PS00345108"],"award-info":[{"award-number":["PS00345108"]}]},{"name":"National Science Foundation","award":["PMD522071138426"],"award-info":[{"award-number":["PMD522071138426"]}]},{"name":"National Science Foundation","award":["NSF-OIA-2119809"],"award-info":[{"award-number":["NSF-OIA-2119809"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Conventional mild hydrotreatment processes of bio-oil present significant challenges of a high degree of polymerization, a low oil yield, high coke formation, and poor catalyst recovery. To address these challenges, the current study looked into investigating and enhancing the properties of raw bio-oil organic phase samples via a solvent-assisted stabilization approach using methanol (METH), ethanol (ETH), isopropyl alcohol (IPA), and ethyl ether (DME). Solvents like methanol (METH) and ethanol (ETH), which are highly polar, yielded higher oil fractions (64% and 62%, respectively) compared to less polar solvents like ethyl ether (DME) at 59%. Isopropyl alcohol (IPA), with intermediate polarity, achieved a balanced oil yield of 63%, indicating its ability to dissolve both polar and non-polar components. Moisture reduction in stabilized bio-oils followed the order IPA &gt; ETH &gt; METH &gt; DME, with IPA showing the highest reduction due to its structural characteristics facilitating dehydration. Viscosity reduction varied, with IPA &gt; ETH &gt; DME &gt; METH. Carbon recovery in stabilized bio-oils ranged from 65% to 75% for DME, ETH, and METH and was 71% for IPA. The heating values of stabilized bio-oils ranged from 28 to 29 MJ\/kg, with IPA-stabilized bio-oil showing the highest value (29.05 \u00b1 0.06 MJ\/kg). METH demonstrated high efficiency (74.8%) in stabilizing bio-oil, attributed to its strong hydrogen-donating capability. ETH followed closely at 69.5%, indicating its comparable performance in bio-oil stabilization. With moderate efficiency (69.3%), IPA presents a balanced alternative considering its molecular structure and hydrogen solubility. In contrast, DME exhibited lower efficiency (63.6%) due to its weaker hydrogenation capability and propensity for undesired side reactions. The current study suggests that subcritical conditions up to 200 \u00b0C are adequate for METH, ETH, and IPA in bio-oil stabilization, comparable to results obtained under supercritical conditions.<\/jats:p>","DOI":"10.3390\/bioengineering12050537","type":"journal-article","created":{"date-parts":[[2025,5,16]],"date-time":"2025-05-16T06:57:28Z","timestamp":1747378648000},"page":"537","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Stabilization of the Bio-Oil Organic Phase via Solvent-Assisted Hydrotreating, Part 1: Investigating the Influence of Various Solvents"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4003-8970","authenticated-orcid":false,"given":"Manqoba","family":"Shezi","sequence":"first","affiliation":[{"name":"Department of Chemical Engineering, Durban University of Technology, Durban 4000, South Africa"},{"name":"Department of Biosystems Engineering, Auburn University, 200 Corley Building, Auburn, AL 36849, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4408-9097","authenticated-orcid":false,"given":"Manish","family":"Sakhakarmy","sequence":"additional","affiliation":[{"name":"ASI Industrial, 1300 Minnesota Ave, Billings, MT 59101, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6539-6822","authenticated-orcid":false,"given":"Sushil","family":"Adhikari","sequence":"additional","affiliation":[{"name":"Department of Biosystems Engineering, Auburn University, 200 Corley Building, Auburn, AL 36849, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sammy Lewis","family":"Kiambi","sequence":"additional","affiliation":[{"name":"Chemical Engineering Department, Vaal University of Technology, Vanderbijlpark 1900, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"S\u00e1nchez, J., Curt, M.D., Robert, N., and Fern\u00e1ndez, J. (2019). Biomass resources. The Role of Bioenergy in the Bioeconomy, Elsevier.","DOI":"10.1016\/B978-0-12-813056-8.00002-9"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1016\/S0196-8904(01)00037-1","article-title":"Conversion of cotton cocoon shell to hydrogen rich gaseous products by pyrolysis","volume":"43","year":"2002","journal-title":"Energy Convers. Manag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"127790","DOI":"10.1016\/j.fuel.2023.127790","article-title":"A comprehensive review on thermochemical, and biochemical conversion methods of lignocellulosic biomass into valuable end product","volume":"342","author":"Awasthi","year":"2023","journal-title":"Fuel"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1712","DOI":"10.1007\/s10163-020-01063-w","article-title":"Comprehensive review on pyrolytic oil production, upgrading and its utilization","volume":"22","author":"Pawar","year":"2020","journal-title":"J. Mater. Cycles Waste Manag."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1016\/j.catcom.2009.09.002","article-title":"Upgrading of bio-oil: Effect of light aldehydes on acetic acid removal via esterification","volume":"11","author":"Lohitharn","year":"2009","journal-title":"Catal. Commun."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"7080","DOI":"10.1021\/acssuschemeng.8b06860","article-title":"Quantitative Study of straw bio-oil hydrodeoxygenation over a sulfided nimo catalyst","volume":"7","author":"Auersvald","year":"2019","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2454","DOI":"10.1021\/ef300252y","article-title":"Development of the Basis for an analytical protocol for feeds and products of bio-oil hydrotreatment","volume":"26","author":"Oasmaa","year":"2012","journal-title":"Energy Fuels"},{"key":"ref_8","first-page":"776","article-title":"Catalytic upgrading of bio-oil from bagasse: Thermogravimetric analysis and fixed bed pyrolysis","volume":"7","author":"Garba","year":"2018","journal-title":"Beni-Suef Univ. J. Basic Appl. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1543","DOI":"10.1016\/j.rser.2015.12.180","article-title":"A review on the upgradation techniques of pyrolysis oil","volume":"58","author":"Gollakota","year":"2016","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"107753","DOI":"10.1016\/j.fuproc.2023.107753","article-title":"Hydrotreatment of pyrolysis bio-oil with non-edible carinata oil and poultry fat for producing transportation fuels","volume":"245","author":"Roy","year":"2023","journal-title":"Fuel Process. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1016\/j.fuproc.2014.03.029","article-title":"Hydrotreatment of corn stover bio-oil using noble metal catalysts","volume":"125","author":"Capunitan","year":"2014","journal-title":"Fuel Process. Technol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"15149","DOI":"10.1021\/acssuschemeng.0c03896","article-title":"Efficient one-stage bio-oil upgrading over sulfided catalysts","volume":"8","author":"Shumeiko","year":"2020","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"106140","DOI":"10.1016\/j.fuproc.2019.106140","article-title":"Hydrotreatment of pyrolysis bio-oil: A review","volume":"195","author":"Han","year":"2019","journal-title":"Fuel Process. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.apcata.2011.08.046","article-title":"A review of catalytic upgrading of bio-oil to engine fuels","volume":"407","author":"Mortensen","year":"2011","journal-title":"Appl. Catal. A Gen."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.fuproc.2014.01.039","article-title":"Hydrodeoxygenation of fast-pyrolysis bio-oils from various feedstocks using carbon-supported catalysts","volume":"123","author":"Elkasabi","year":"2014","journal-title":"Fuel Process. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/j.fuproc.2016.05.014","article-title":"Importance of hydrogen and bio-oil inlet temperature during the hydrotreatment of bio-oil","volume":"150","author":"Gholizadeh","year":"2016","journal-title":"Fuel Process. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"17008","DOI":"10.1021\/acs.energyfuels.1c01700","article-title":"Advances and Challenges in the valorization of bio-oil: Hydrodeoxygenation using carbon-supported catalysts","volume":"35","author":"Cordero","year":"2021","journal-title":"Energy Fuels"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1016\/j.apcata.2011.08.024","article-title":"Hydrotreatment of wood-based pyrolysis oil using zirconia-supported mono-and bimetallic (Pt, Pd, Rh) catalysts","volume":"407","author":"Ardiyanti","year":"2011","journal-title":"Appl. Catal. A Gen."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Shezi, M., and Kiambi, S.L. (2025). Isothermal Pyrolysis of Bamboo and Pinewood Biomass: Product Characterization and Comparative Study in a Fluidized Bed Reactor. Bioengineering, 12.","DOI":"10.3390\/bioengineering12020099"},{"key":"ref_20","unstructured":"(2021). Standard Test Methods for Determination of Carbon, Hydrogen and Nitrogen in Analysis Samples of Coal and Carbon in Analysis Samples of Coal and Coke (Standard No. ASTM D5373)."},{"key":"ref_21","unstructured":"(2021). Standard Test Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants (Standard No. ASTM D5291)."},{"key":"ref_22","unstructured":"(2010). Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration (Standard No. ASTM D664-07)."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"119329","DOI":"10.1016\/j.fuel.2020.119329","article-title":"Upgrading of bio-oil from thermochemical conversion of various biomass\u2013Mechanism, challenges and opportunities","volume":"287","author":"Ahamed","year":"2021","journal-title":"Fuel"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"702","DOI":"10.1007\/s11705-019-1861-9","article-title":"Production of renewable fuels by blending bio-oil with alcohols and upgrading under supercritical conditions","volume":"13","author":"Omar","year":"2019","journal-title":"Front. Chem. Sci. Eng."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Yu, F., Deng, S., Chen, P., Liu, Y., Wan, Y., Olson, A., Kittelson, D., and Ruan, R. (2007). Physical and chemical properties of bio-oils from microwave pyrolysis of corn stover. Applied Biochemistry and Biotecnology: The Twenty-Eighth Symposium, Proceedings of the Twenty-Eight Symposium on Biotechnology for Fuels and Chemicals, Nashville, TN, USA, 30 April\u20133 May 2006, Springer.","DOI":"10.1007\/978-1-60327-181-3_78"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1016\/j.jaap.2016.04.012","article-title":"Effect of in-situ addition of alcohol on yields and properties of bio-oil derived from fast pyrolysis of eucalyptus bark","volume":"120","author":"Pidtasang","year":"2016","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"100834","DOI":"10.1016\/j.pecs.2020.100834","article-title":"Spray combustion of fast pyrolysis bio-oils: Applications, challenges, and potential solutions","volume":"79","author":"Broumand","year":"2020","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"663","DOI":"10.1080\/17597269.2016.1141276","article-title":"Bio-oil: The future of hydrogen generation","volume":"8","author":"Kumar","year":"2016","journal-title":"Biofuels"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.indcrop.2016.12.004","article-title":"Production of conjugated linoleic acid-rich cottonseed oil by supported Ru catalyzed isomerization","volume":"97","author":"Liu","year":"2017","journal-title":"Ind. Crops Prod."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1016\/j.wasman.2020.04.035","article-title":"Reaction pathway of poly(ethylene) terephthalate carbonization: Decomposition behavior based on carbonized product","volume":"108","author":"Chia","year":"2020","journal-title":"Waste Manag."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1002\/ente.201600096","article-title":"A Perspective on catalytic strategies for deoxygenation in biomass pyrolysis","volume":"5","author":"Nolte","year":"2016","journal-title":"Energy Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1293","DOI":"10.1016\/j.rser.2015.12.146","article-title":"Production of renewable diesel through the hydroprocessing of lignocellulosic biomass-derived bio-oil: A review","volume":"58","author":"Patel","year":"2016","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"178","DOI":"10.1016\/j.fuproc.2016.08.030","article-title":"Bio-oil upgrading in supercritical water using Ni-Co catalysts supported on carbon nanofibres","volume":"154","author":"Arauzo","year":"2016","journal-title":"Fuel Process. Technol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.egypro.2017.03.277","article-title":"Microwave Pyrolysis of lignocellulosic biomass","volume":"105","author":"Lo","year":"2017","journal-title":"Energy Procedia"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Kim, J.-S., and Choi, G.-G. (2018). Pyrolysis of lignocellulosic biomass for biochemical production. Waste Biorefinery, Elsevier.","DOI":"10.1016\/B978-0-444-63992-9.00011-2"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1016\/j.biortech.2011.12.125","article-title":"Production of phenols and biofuels by catalytic microwave pyrolysis of lignocellulosic biomass","volume":"108","author":"Bu","year":"2012","journal-title":"Bioresour. Technol."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Pecha, M.B., and Garcia-Perez, M. (2020). Pyrolysis of lignocellulosic biomass: Oil, char, and gas. Bioenergy, Elsevier.","DOI":"10.1016\/B978-0-12-815497-7.00029-4"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1039\/C3GC41382A","article-title":"A review and perspective of recent bio-oil hydrotreating research","volume":"16","author":"Zacher","year":"2014","journal-title":"Green Chem."}],"container-title":["Bioengineering"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-5354\/12\/5\/537\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:33:51Z","timestamp":1760031231000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-5354\/12\/5\/537"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,16]]},"references-count":38,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2025,5]]}},"alternative-id":["bioengineering12050537"],"URL":"https:\/\/doi.org\/10.3390\/bioengineering12050537","relation":{},"ISSN":["2306-5354"],"issn-type":[{"value":"2306-5354","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,5,16]]}}}