Abstract
Conventional biorefinery processes are complex, engineered and energy-intensive, where biomass fractionation, a key functional step for the production of biomass-derived chemical substances, demands industrial organic solvents and harsh, environmentally harmful reaction conditions. There is a timely, clear and unmet economic need for a systematic, robust and affordable conversion method technology to become greener, sustainable and cost-effective. In this perspective, deep eutectic solvents (DESs) have been envisaged as the most advanced novel polar liquids that are entirely made of natural, molecular compounds that are capable of an association via hydrogen bonding interactions. DES has quickly emerged in various application functions thanks to a formulations’ simple preparation. These molecules themselves are biobased, renewable, biodegradable and eco-friendly. The present experimental review is providing the state of the art topical overview of trends regarding the employment of DESs in investigated biorefinery-related techniques. This review covers DESs for lignocellulosic component isolation, applications as (co)catalysts and their functionality range in biocatalysis. Furthermore, a special section of the DESs recyclability is included. For DESs to unlock numerous new (reactive) possibilities in future biorefineries, the critical estimation of its complexity in the reaction, separation, or fractionation medium should be addressed more in future studies.
Funding source: Slovenian Research Agency (ARRS)
Award Identifier / Grant number: 722361
Funding source: European Regional Development Fund
Funding source: Ministry of Education, Science and Sport
Funding source: Slovenian Research Agency (ARRS)
Award Identifier / Grant number: Z2-9200
About the authors
Dr. Ana Bjelić is a researcher at the National Institute of Chemistry, Slovenia. She received her Master’s degree in Chemical Engineering at the University of Belgrade in 2013 and completed her PhD in Chemical Engineering at the University of Ljubljana in 2018. Her main areas of research include lignin valorisation into value-added chemicals and micro-kinetic modelling. She has published 6 papers in high impact research journals since she received her BS degree in 2012.
Dr. Brigita Hočevar obtained her BSc and MSc degrees in Chemical Engineering from the University of Ljubljana, Slovenia, followed by her PhD from the Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Slovenia. Her research involves the sustainable chemocatalytic production of biobased monomers from lignocellulosic biomass and microkinetic modelling of the heterogeneous chemocatalytic processes.
Assoc. Prof. Dr. Miha Grilc became the biomass-valorisation group leader at Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Ljubljana, Slovenia in 2015. He was awarded the “Jožef Stefan” Golden Emblem Prize for the most promising and notable PhD theses in Science and Mathematics, Technology and Medicine and Biotechnology for the last three years. His main expertise lies in modelling of the reaction kinetics, transport phenomena and fluid dynamics in multiphase catalytic contactors (reactors).
Dr. Uroš Novak finished his PhD in Chemical Engineering in 2014 and has published more than 20 original scientific articles and 80 other contributions. In 2019, he was awarded the Excellence in Science Award given by Slovenia Research Agency. Dr. Novak is the research group leader for sustainable processing at the Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Slovenia. His expertise lies in (bio)chemical process optimization, process intensification, biomass valorization and biopolymer technology.
Prof. Dr Blaž Likozar earned his PhD in Chemical Engineering at the University of Ljubljana in 2008. He has been a member of NIC since 2011, working as the head of department in the field of chemical engineering (Department of Catalysis and Chemical Reaction Engineering). His expertise lies in heterogeneous catalyst materials, modelling, simulation and optimization of process fluid mechanics, transport phenomena and chemical kinetics. From 2014 to 2015, he worked as a Fulbright Program researcher at the University of Delaware.
Acknowledgments
For the English language editing, we would like to thank Mr. Brett Pomeroy.
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Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
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Research funding: The study was funded by the Slovenian Research Agency (ARRS) through the Programme P2–0152, European Union’s Horizon 2020 research and innovation programme, for funding Rhodolive project (grant number 722361) and Project Z2-9200. The work was partially carried out within the RDI project Cel. Cycle: »Potential of biomass for development of advanced materials and biobased products«, which is cofinanced by the Republic of Slovenia, Ministry of Education, Science and Sport, and European Union through the European Regional Development Fund, 2016-2020.
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Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
References
Abbott, A.P., Capper, G., Davies, D.L., Rasheed, R.K., and Tambyrajah, V. (2003). Novel solvent properties of choline chloride/urea mixtures. Chem. Commun. 70–71, https://doi.org/10.1039/b210714g.Search in Google Scholar PubMed
Abougor, H. (2014). Utilization of deep eutectic solvents as a pretreatment option for lignocellulosic biomass, ProQuest Dissertations and Theses. Tennessee, Tennessee Technological University.Search in Google Scholar
Alhassan, Y., Kumar, N., and Bugaje, I.M. (2016a). Catalytic upgrading of waste tire pyrolysis oil via supercritical esterification with deep eutectic solvents (green solvents and catalysts). J. Energy Inst. 89: 683–693, https://doi.org/10.1016/j.joei.2015.05.003.Search in Google Scholar
Alhassan, Y., Kumar, N., and Bugaje, I.M. (2016b). Hydrothermal liquefaction of de-oiled Jatropha curcas cake using Deep Eutectic Solvents (DESs) as catalysts and co-solvents. Bioresour. Technol. 199: 375–381, https://doi.org/10.1016/j.biortech.2015.07.116.Search in Google Scholar PubMed
Alvarez-Vasco, C., Ma, R., Quintero, M., Guo, M., Geleynse, S., Ramasamy, K.K., Wolcott, M., and Zhang, X. (2016). Unique low-molecular-weight lignin with high purity extracted from wood by deep eutectic solvents (DES): a source of lignin for valorization. Green Chem. 18: 5133–5141, https://doi.org/10.1039/c6gc01007e.Search in Google Scholar
Amić, A. and Molnar, M. (2017). An improved and efficient N-acetylation of amines using choline chloride based deep eutectic solvents. Org. Prep. Proced. Int. 49: 249–257, https://doi.org/10.1080/00304948.2017.1320914.Search in Google Scholar
An, Y.-X., Zong, M.-H., Wu, H., and Li, N. (2015). Pretreatment of lignocellulosic biomass with renewable cholinium ionic liquids: biomass fractionation, enzymatic digestion and ionic liquid reuse. Bioresour. Technol. 192: 165–171, https://doi.org/10.1016/j.biortech.2015.05.064.Search in Google Scholar PubMed
Azizi, N. and Edrisi, M. (2017). Deep eutectic solvent immobilized on SBA-15 as a novel separable catalyst for one-pot three-component Mannich reaction. Microporous Mesoporous Mater. 240: 130–136, https://doi.org/10.1016/j.micromeso.2016.11.009.Search in Google Scholar
Azizi, N., Dezfooli, S., Khajeh, M., and Hashemi, M.M. (2013). Efficient deep eutectic solvents catalyzed synthesis of pyran and benzopyran derivatives. J. Mol. Liq. 186: 76–80, https://doi.org/10.1016/j.molliq.2013.05.011.Search in Google Scholar
Behalo, M.S., Bloise, E., Mele, G., Salomone, A., Messa, F., Carbone, L., Mazzetto, S.E., and Lomonaco, D. (2020). Bio-based benzoxazines synthesized in a deep eutectic solvent: a greener approach toward vesicular nanosystems. J. Heterocycl. Chem. 57: 768–773, https://doi.org/10.1002/jhet.3818.Search in Google Scholar
Bhosle, M.R., Khillare, L.D., Dhumal, S.T., and Mane, R.A. (2016). A facile synthesis of 6-amino-2H, 4H-pyrano[2,3-с]pyrazole-5-carbonitriles in deep eutectic solvent. Chin. Chem. Lett. 27: 370–374, https://doi.org/10.1016/j.cclet.2015.12.005.Search in Google Scholar
Bi, W., Tian, M., and Row, K.H. (2013). Evaluation of alcohol-based deep eutectic solvent in extraction and determination of flavonoids with response surface methodology optimization. J. Chromatogr. A 1285: 22–30, https://doi.org/10.1016/j.chroma.2013.02.041.Search in Google Scholar PubMed
Bosiljkov, T., Dujmić, F., Cvjetko Bubalo, M., Hribar, J., Vidrih, R., Brnčić, M., Zlatic, E., Radojčić Redovniković, I., and Jokić, S. (2017). Natural deep eutectic solvents and ultrasound-assisted extraction: green approaches for extraction of wine lees anthocyanins. Food Bioprod. Process. 102: 195–203, https://doi.org/10.1016/j.fbp.2016.12.005.Search in Google Scholar
Bradić, B., Novak, U., and Likozar, B. (2019). Crustacean shell bio-refining to chitin by natural deep eutectic solvents. Green Process. Synth. 9: 13, https://doi.org/10.1515/gps-2020-0002.Search in Google Scholar
Brenna, D., Massolo, E., Puglisi, A., Rossi, S., Celentano, G., Benaglia, M., and Capriati, V. (2016). Towards the development of continuous, organocatalytic, and stereoselective reactions in deep eutectic solvents. Beilstein J. Org. Chem. 12: 2620–2626, https://doi.org/10.3762/bjoc.12.258.Search in Google Scholar PubMed PubMed Central
Chen, Y. and Mu, T. (2019). Application of deep eutectic solvents in biomass pretreatment and conversion. Green Energy Environ. 4: 95–115, https://doi.org/10.1016/j.gee.2019.01.012.Search in Google Scholar
Chen, Z., Bai, X., and Wan, C. (2018). High-solid lignocellulose processing enabled by natural deep eutectic solvent for lignin extraction and industrially relevant production of renewable chemicals. ACS Sustain. Chem. Eng. 6: 12205–12216, https://doi.org/10.1021/acssuschemeng.8b02541.Search in Google Scholar
Chirea, M., Freitas, A., Vasile, B.S., Ghitulica, C., Pereira, C.M., and Silva, F. (2011). Gold nanowire networks: synthesis, characterization, and catalytic activity. Langmuir 27: 3906–3913, https://doi.org/10.1021/la104092b.Search in Google Scholar PubMed
Cvjetko Bubalo, M., Tušek, A.J., VinkoviĿ, M., RadoševiĿ, K., SrĿek, V.G., and RedovnikoviĿ, I.R. (2015). Cholinium-based deep eutectic solvents and ionic liquids for lipase-catalyzed synthesis of butyl acetate. J. Mol. Catal. B Enzym. 122: 188–198, https://doi.org/10.1016/j.molcatb.2015.09.005.Search in Google Scholar
da Costa Lopes, A.M. and Bogel-Łukasik, R. (2015). Acidic ionic liquids as sustainable approach of cellulose and lignocellulosic biomass conversion without additional catalysts. ChemSusChem 8: 947–965, https://doi.org/10.1002/cssc.201402950.Search in Google Scholar PubMed
da Costa Lopes, A.M., João, K.G., Morais, A.R.C., Bogel-Łukasik, E., and Bogel-Łukasik, R. (2013). Ionic liquids as a tool for lignocellulosic biomass fractionation. Sustain. Chem. Process. 1: 3, https://doi.org/10.1186/2043-7129-1-3.Search in Google Scholar
da Costa Lopes, A.M., Gomes, J.R.B., Coutinho, J.A.P., and Silvestre, A.J.D. (2020). Novel insights into biomass delignification with acidic deep eutectic solvents: a mechanistic study of β-O-4 ether bond cleavage and the role of the halide counterion in the catalytic performance. Green Chem. 22: 2474–2487, https://doi.org/10.1039/c9gc02569c.Search in Google Scholar
Dai, Y., van Spronsen, J., Witkamp, G.-J., Verpoorte, R., and Choi, Y.H. (2013). Natural deep eutectic solvents as new potential media for green technology. Anal. Chim. Acta 766: 61–68, https://doi.org/10.1016/j.aca.2012.12.019.Search in Google Scholar PubMed
Dai, Y., Huan, B., Zhang, H.-S., and He, Y.-C. (2017). Effective biotransformation of ethyl 4-chloro-3-oxobutanoate into ethyl (S)-4-Chloro-3-Hydroxybutanoate by recombinant E. coli CCZU-T15 whole cells in [ChCl][Gly]–Water media. Appl. Biochem. Biotechnol. 181: 1347–1359, https://doi.org/10.1007/s12010-016-2288-0.Search in Google Scholar PubMed
de Carvalho, C.C.C.R. (2011). Enzymatic and whole cell catalysis: finding new strategies for old processes. Biotechnol. Adv. 29: 75–83, https://doi.org/10.1016/j.biotechadv.2010.09.001.Search in Google Scholar PubMed
de Dios, SL, 2013. Phase equilibria for extraction processes with designer solvents. Universidade de Santiago de Compostela. Departamento de Enxeñaría Químic, Santiago de Compostela.Search in Google Scholar
de Gonzalo, G., Martin, C., and Fraaije, M.W. (2020). Positive impact of natural deep eutectic solvents on the biocatalytic performance of 5-hydroxymethyl-furfural oxidase. Catalysts 10: 447, https://doi.org/10.3390/catal10040447.Search in Google Scholar
De Santi, V., Cardellini, F., Brinchi, L., and Germani, R. (2012). Novel Brønsted acidic deep eutectic solvent as reaction media for esterification of carboxylic acid with alcohols. Tetrahedron Lett. 53: 5151–5155, https://doi.org/10.1016/j.tetlet.2012.07.063.Search in Google Scholar
DeSimone, J.M. (2002). Practical approaches to green solvents. Science 297: 799–803, https://doi.org/10.1126/science.1069622.Search in Google Scholar PubMed
Di Marino, D., Stöckmann, D., Kriescher, S., Stiefel, S., and Wessling, M. (2016). Electrochemical depolymerisation of lignin in a deep eutectic solvent. Green Chem. 18: 6021–6028, https://doi.org/10.1039/c6gc01353h.Search in Google Scholar
Durand, E., Lecomte, J., Baréa, B., Piombo, G., Dubreucq, E., and Villeneuve, P. (2012). Evaluation of deep eutectic solvents as new media for Candida antarctica B lipase catalyzed reactions. Process Biochem. 47: 2081–2089, https://doi.org/10.1016/j.procbio.2012.07.027.Search in Google Scholar
Durand, E., Lecomte, J., Baréa, B., Dubreucq, E., Lortie, R., and Villeneuve, P. (2013). Evaluation of deep eutectic solvent–water binary mixtures for lipase-catalyzed lipophilization of phenolic acids. Green Chem. 15: 2275–2282, https://doi.org/10.1039/c3gc40899j.Search in Google Scholar
Durand, E., Lecomte, J., Baréa, B., and Villeneuve, P. (2014). Towards a better understanding of how to improve lipase-catalyzed reactions using deep eutectic solvents based on choline chloride. Eur. J. Lipid Sci. Technol. 116: 16–23, https://doi.org/10.1002/ejlt.201300246.Search in Google Scholar
Elgharbawy, A.A.M., Hayyan, M., Hayyan, A., Basirun, W.J., Salleh, H.M., and Mirghani, M.E.S. (2020). A grand avenue to integrate deep eutectic solvents into biomass processing. Biomass Bioenerg. 137: 105550, https://doi.org/10.1016/j.biombioe.2020.105550.Search in Google Scholar
Fang, C., Thomsen, M.H., Frankær, C.G., Brudecki, G.P., Schmidt, J.E., and AlNashef, I.M. (2017). Reviving pretreatment effectiveness of deep eutectic solvents on lignocellulosic date palm residues by prior recalcitrance reduction. Ind. Eng. Chem. Res. 56: 3167–3174, https://doi.org/10.1021/acs.iecr.6b04733.Search in Google Scholar
Fotiadou, R., Patila, M., Hammami, M.A., Enotiadis, A., Moschovas, D., Tsirka, K., Spyrou, K., Giannelis, E.P., Avgeropoulos, A., Paipetis, A., et al. (2019). Development of effective lipase-hybrid nanoflowers enriched with carbon and magnetic nanomaterials for biocatalytic transformations. Nanomaterials 9: 808, https://doi.org/10.3390/nano9060808.Search in Google Scholar PubMed PubMed Central
Francisco, M., van den Bruinhorst, A., and Kroon, M.C. (2012). New natural and renewable low transition temperature mixtures (LTTMs): screening as solvents for lignocellulosic biomass processing. Green Chem. 14: 2153–2157, https://doi.org/10.1039/c2gc35660k.Search in Google Scholar
Fredes, Y., Chamorro, L., and Cabrera, Z. (2019). Increased selectivity of novozym 435 in the asymmetric hydrolysis of a substrate with high hydrophobicity through the use of deep eutectic solvents and high substrate concentrations. Molecules 24: 792, https://doi.org/10.3390/molecules24040792.Search in Google Scholar PubMed PubMed Central
George, A., Brandt, A., Tran, K., Zahari, S.M.S.N.S., Klein-Marcuschamer, D., Sun, N., Sathitsuksanoh, N., Shi, J., Stavila, V., Parthasarathi, R., et al. (2015). Design of low-cost ionic liquids for lignocellulosic biomass pretreatment. Green Chem. 17: 1728–1734, https://doi.org/10.1039/c4gc01208a.Search in Google Scholar
González-Martínez, D., Gotor, V., and Gotor-Fernández, V. (2016). Application of deep eutectic solvents in promiscuous lipase-catalysed aldol reactions. Eur. J. Org Chem. 2016: 1513–1519, https://doi.org/10.1002/ejoc.201501553.Search in Google Scholar
Gorke, J.T., Kazlauskas, R.J., and Srienc, F., 2008a. Enzymatic processing in deep eutectic solvents, United States patent US 8,247,198.Search in Google Scholar
Gorke, J.T., Srienc, F., and Kazlauskas, R.J. (2008b). Hydrolase-catalyzed biotransformations in deep eutectic solvents. Chem. Commun. 1235–1237, https://doi.org/10.1039/b716317g.Search in Google Scholar PubMed
Gorke, J., Srienc, F., and Kazlauskas, R. (2010). Toward advanced ionic liquids. Polar, enzyme-friendly solvents for biocatalysis. Biotechnol. Bioproc. Eng. 15: 40–53, https://doi.org/10.1007/s12257-009-3079-z.Search in Google Scholar PubMed PubMed Central
Gotor-Fernández, V. and Paul, C.E. (2019). Deep eutectic solvents for redox biocatalysis. J. Biotechnol. 293: 24–35, https://doi.org/10.1016/j.jbiotec.2018.12.018.Search in Google Scholar PubMed
Guajardo, N. and Domínguez de María, P. (2019). Continuous biocatalysis in environmentally-friendly media: a triple synergy for future sustainable processes. ChemCatChem 11: 3128–3137 https://doi.org/10.1002/cctc.201900773.Search in Google Scholar
Guajardo, N., Ahumada, K., Domínguez de María, P., and Schrebler, R.A. (2019). Remarkable stability of Candida Antarctica lipase B immobilized via cross-linking aggregates (CLEA) in deep eutectic solvents. Biocatal. Biotransform. 37: 106–114, https://doi.org/10.1080/10242422.2018.1492567.Search in Google Scholar
Guajardo, N., Ahumada, K., and Domínguez de María, P. (2020). Immobilized lipase-CLEA aggregates encapsulated in lentikats® as robust biocatalysts for continuous processes in deep eutectic solvents. J. Biotechnol. 310: 97–102, https://doi.org/10.1016/j.jbiotec.2020.02.003.Search in Google Scholar PubMed
Guo, Q. and Zhao, J.C.G. (2013). Highly enantioselective three-component direct mannich reactions of unfunctionalized ketones catalyzed by bifunctional organocatalysts. Org. Lett. 15: 508–511, https://doi.org/10.1021/ol303315c.Search in Google Scholar PubMed PubMed Central
Gutiérrez, M.C., Ferrer, M.L., Yuste, L., Rojo, F., and del Monte, F. (2010). Bacteria incorporation in deep-eutectic solvents through freeze-drying. Angew. Chem. Int. Ed. 49: 2158–2162, https://doi.org/10.1002/anie.200905212.Search in Google Scholar PubMed
Haerens, K., Van Deuren, S., Matthijs, E., and Van der Bruggen, B. (2010). Challenges for recycling ionic liquids by using pressure driven membrane processes. Green Chem. 12: 2182–2188, https://doi.org/10.1039/c0gc00406e.Search in Google Scholar
Hayyan, A., Ali Hashim, M., Mjalli, F.S., Hayyan, M., and AlNashef, I.M. (2013). A novel phosphonium-based deep eutectic catalyst for biodiesel production from industrial low grade crude palm oil. Chem. Eng. Sci. 92: 81–88, https://doi.org/10.1016/j.ces.2012.12.024.Search in Google Scholar
Hayyan, A., Hashim, M.A., Hayyan, M., Mjalli, F.S., and AlNashef, I.M. (2014). A new processing route for cleaner production of biodiesel fuel using a choline chloride based deep eutectic solvent. J. Clean. Prod. 65: 246–251, https://doi.org/10.1016/j.jclepro.2013.08.031.Search in Google Scholar
Hiltunen, J., Kuutti, L., Rovio, S., Puhakka, E., Virtanen, T., Ohra-Aho, T., and Vuoti, S. (2016). Using a low melting solvent mixture to extract value from wood biomass. Sci. Rep. 6: 32420, https://doi.org/10.1038/srep32420.Search in Google Scholar PubMed PubMed Central
Hong, S., Shen, X.-J., Bo, P., Xue, Z., Cao, X., Wen, J.-L., Sun, Z., Lam, S.S., Yuan, T.-Q., and Sun, R. (2020). In depth interpret the structural changes of lignin and formation of diketones during acidic deep eutectic solvent pretreatment. Green Chem 22: 1851–1858, https://doi.org/10.1039/d0gc00006j.10.1039/D0GC00006JSearch in Google Scholar
Huang, Z.-L., Wu, B.-P., Wen, Q., Yang, T.-X., and Yang, Z. (2014). Deep eutectic solvents can be viable enzyme activators and stabilizers. J. Chem. Technol. Biotechnol. 89: 1975–1981, https://doi.org/10.1002/jctb.4285.Search in Google Scholar
Hümmer, M., Kara, S., Liese, A., Huth, I., Schrader, J., and Holtmann, D. (2018). Synthesis of (-)-menthol fatty acid esters in and from (-)-menthol and fatty acids – novel concept for lipase catalyzed esterification based on eutectic solvents. Mol. Catal. 458: 67–72, https://doi.org/10.1016/j.mcat.2018.08.003.Search in Google Scholar
Imai, T., Yokoyama, T., and Matsumoto, Y. (2011). Revisiting the mechanism of β-O-4 bond cleavage during acidolysis of lignin IV: dependence of acidolysis reaction on the type of acid. J. Wood Sci. 57: 219–225, https://doi.org/10.1007/s10086-010-1166-6.Search in Google Scholar
Islam, M.K., Wang, H., Rehman, S., Dong, C., Hsu, H.-Y., Lin, C.S.K., and Leu, S.-Y. (2020). Sustainability metrics of pretreatment processes in a waste derived lignocellulosic biomass biorefinery. Bioresour. Technol. 298: 122558, https://doi.org/10.1016/j.biortech.2019.122558.Search in Google Scholar PubMed
Jablonský, M., Škulcová, A., Kamenská, L., Vrška, M., and Šíma, J. (2015). Deep eutectic solvents: fractionation of wheat straw. BioResources 10: 9, https://doi.org/10.15376/biores.10.4.8039-8047.Search in Google Scholar
Jeong, K.M., Lee, M.S., Nam, M.W., Zhao, J., Jin, Y., Lee, D.-K., Kwon, S.W., Jeong, J.H., and Lee, J. (2015). Tailoring and recycling of deep eutectic solvents as sustainable and efficient extraction media. J. Chromatogr. A 1424: 10–17, https://doi.org/10.1016/j.chroma.2015.10.083.Search in Google Scholar PubMed
Juneidi, I., Hayyan, M., Hashim, M.A., and Hayyan, A. (2017). Pure and aqueous deep eutectic solvents for a lipase-catalysed hydrolysis reaction. Biochem. Eng. J. 117: 129–138, https://doi.org/10.1016/j.bej.2016.10.003.Search in Google Scholar
Kalhor, P. and Ghandi, K. (2019). Deep eutectic solvents for pretreatment, extraction, and catalysis of biomass and food waste. Molecules 24: 4012, https://doi.org/10.3390/molecules24224012.Search in Google Scholar PubMed PubMed Central
Kanbayashi, T. and Miyafuji, H. (2016). Effect of ionic liquid treatment on the ultrastructural and topochemical features of compression wood in Japanese cedar (Cryptomeria japonica). Sci. Rep. 6: 30147, https://doi.org/10.1038/srep30147.Search in Google Scholar PubMed PubMed Central
Kim, K.H., Dutta, T., Sun, J., Simmons, B., and Singh, S. (2018). Biomass pretreatment using deep eutectic solvents from lignin derived phenols. Green Chem. 20: 809–815, https://doi.org/10.1039/c7gc03029k.Search in Google Scholar
Kohli, K., Prajapati, R., and Sharma, B.K. (2019). Bio-Based chemicals from renewable biomass for integrated biorefineries. Energies 12: 233, https://doi.org/10.3390/en12020233.Search in Google Scholar
Krystof, M., Pérez-Sánchez, M., and Domínguez de María, P. (2013). Lipase-Catalyzed (Trans)esterification of 5-hydroxy- methylfurfural and separation from HMF esters using deep-eutectic solvents. ChemSusChem 6: 630–634, https://doi.org/10.1002/cssc.201200931.Search in Google Scholar PubMed
Kumar, A.K., Parikh, B.S., and Pravakar, M. (2016a). Natural deep eutectic solvent mediated pretreatment of rice straw: bioanalytical characterization of lignin extract and enzymatic hydrolysis of pretreated biomass residue. Environ. Sci. Pollut. Control Ser. 23: 9265–9275, https://doi.org/10.1007/s11356-015-4780-4.Search in Google Scholar PubMed
Kumar, A.K., Parikh, B.S., Shah, E., Liu, L.Z., and Cotta, M.A. (2016b). Cellulosic ethanol production from green solvent-pretreated rice straw. Biocatal. Agric. Biotechnol. 7: 14–23, https://doi.org/10.1016/j.bcab.2016.04.008.Search in Google Scholar
Li, C.Y., Cheng, S.Z.D., Ge, J.J., Bai, F., Zhang, J.Z., Mann, I.K., Chien, L.-C., Harris, F.W., and Lotz, B. (2000). Molecular orientations in flat-elongated and helical lamellar crystals of a main-chain nonracemic chiral polyester. J. Am. Chem. Soc. 122: 72–79, https://doi.org/10.1021/ja993249t.Search in Google Scholar
Lian, H., Hong, S., Carranza, A., Mota-Morales, J.D., and Pojman, J.A. (2015). Processing of lignin in urea–zinc chloride deep-eutectic solvent and its use as a filler in a phenol-formaldehyde resin. RSC Adv. 5: 28778–28785, https://doi.org/10.1039/c4ra16734a.Search in Google Scholar
Liang, X., Fu, Y., and Chang, J. (2019). Effective separation, recovery and recycling of deep eutectic solvent after biomass fractionation with membrane-based methodology. Separ. Purif. Technol. 210: 409–416, https://doi.org/10.1016/j.seppur.2018.08.021.Search in Google Scholar
Liang, Y., Duan, W., An, X., Qiao, Y., Tian, Y., and Zhou, H. (2020). Novel betaine-amino acid based natural deep eutectic solvents for enhancing the enzymatic hydrolysis of corncob. Bioresour. Technol. 310: 123389, https://doi.org/10.1016/j.biortech.2020.123389.Search in Google Scholar PubMed
Lindberg, D., de la Fuente Revenga, M., and Widersten, M. (2010). Deep eutectic solvents (DESs) are viable cosolvents for enzyme-catalyzed epoxide hydrolysis. J. Biotechnol. 147: 169–171, https://doi.org/10.1016/j.jbiotec.2010.04.011.Search in Google Scholar PubMed
Liu, Y., Lotero, E., and Goodwin, J.G. (2006). Effect of water on sulfuric acid catalyzed esterification. J. Mol. Catal. Chem. 245: 132–140, https://doi.org/10.1016/j.molcata.2005.09.049.Search in Google Scholar
Liu, S., Ni, Y., Wei, W., Qiu, F., Xu, S., and Ying, A. (2014). Choline chloride and urea based eutectic solvents: effective catalytic systems for the knoevenagel condensation reactions of substituted acetonitriles. J. Chem. Res. 38: 186–188, https://doi.org/10.3184/174751914x13926483381319.Search in Google Scholar
Liu, X., Meng, X.-Y., Xu, Y., Dong, T., Zhang, D.-Y., Guan, H.-X., Zhuang, Y., and Wang, J. (2019a). Enzymatic synthesis of 1-caffeoylglycerol with deep eutectic solvent under continuous microflow conditions. Biochem. Eng. J. 142: 41–49, https://doi.org/10.1016/j.bej.2018.11.007.Search in Google Scholar
Liu, Y., Zheng, J., Xiao, J., He, X., Zhang, K., Yuan, S., Peng, Z., Chen, Z., and Lin, X. (2019b). Enhanced enzymatic hydrolysis and lignin extraction of wheat straw by triethylbenzyl ammonium chloride/lactic acid-based deep eutectic solvent pretreatment. ACS Omega 4: 19829–19839, https://doi.org/10.1021/acsomega.9b02709.Search in Google Scholar PubMed PubMed Central
Lobo, H.R., Singh, B.S., and Shankarling, G.S. (2012). Deep eutectic solvents and glycerol: a simple, environmentally benign and efficient catalyst/reaction media for synthesis of N-aryl phthalimide derivatives. Green Chem. Lett. Rev. 5: 487–533, https://doi.org/10.1080/17518253.2012.669500.Search in Google Scholar
Lozano, P., Alvarez, E., Nieto, S., Villa, R., Bernal, J.M., and Donaire, A. (2019). Biocatalytic synthesis of panthenyl monoacyl esters in ionic liquids and deep eutectic solvents. Green Chem. 21: 3353–3361 https://doi.org/10.1039/c9gc01076a.Search in Google Scholar
Mamilla, J.L.K., Novak, U., Grilc, M., and Likozar, B. (2019). Natural deep eutectic solvents (DES) for fractionation of waste lignocellulosic biomass and its cascade conversion to value-added bio-based chemicals. Biomass Bioenerg. 120: 417–425, https://doi.org/10.1016/j.biombioe.2018.12.002.Search in Google Scholar
Mao, S., Yu, L., Ji, S., Liu, X., and Lu, F. (2016). Evaluation of deep eutectic solvents as co-solvent for steroids 1-en-dehydrogenation biotransformation by Arthrobacter simplex. J. Chem. Technol. Biotechnol. 91: 1099–1104, https://doi.org/10.1002/jctb.4691.Search in Google Scholar
Maugeri, Z. and Domínguez de María, P. (2014a). Benzaldehyde lyase (BAL)-catalyzed enantioselective CC bond formation in deep-eutectic-solvents–buffer mixtures. J. Mol. Catal. B Enzym. 107: 120–123, https://doi.org/10.1016/j.molcatb.2014.06.003.Search in Google Scholar
Maugeri, Z. and Domínguez de María, P. (2014b). Whole-cell biocatalysis in deep-eutectic-solvents/aqueous mixtures. ChemCatChem 6: 1535–1537, https://doi.org/10.1002/cctc.201400077.Search in Google Scholar
Maugeri, Z., Leitner, W., and Domínguez de María, P. (2012). Practical separation of alcohol–ester mixtures using deep-eutectic-solvents. Tetrahedron Lett. 53: 6968–6971, https://doi.org/10.1016/j.tetlet.2012.10.044.Search in Google Scholar
Maugeri, Z., Leitner, W., and Domínguez de María, P. (2013). Chymotrypsin-Catalyzed peptide synthesis in deep eutectic solvents. Eur. J. Org Chem. 2013: 4223–4228, https://doi.org/10.1002/ejoc.201300448.Search in Google Scholar
Milker, S., Pätzold, M., Bloh, J.Z., and Holtmann, D. (2019). Comparison of deep eutectic solvents and solvent-free reaction conditions for aldol production. Mol. Catal. 466: 70–74, https://doi.org/10.1016/j.mcat.2019.01.012.Search in Google Scholar
Minami, E., Bito, D., Kawamoto, H., and Saka, S. (2020). Improving saccharide concentration by mixing octyl acetate during semi-flow, hot-compressed water treatment of woody biomass. Biomass Bioenerg 137: 105552, https://doi.org/10.1016/j.biombioe.2020.105552.Search in Google Scholar
Moity, L., Durand, M., Benazzouz, A., Pierlot, C., Molinier, V., and Aubry, J.-M. (2012). Panorama of sustainable solvents using the COSMO-RS approach. Green Chem. 14: 1132–1145, https://doi.org/10.1039/c2gc16515e.Search in Google Scholar
Monhemi, H., Housaindokht, M.R., Moosavi-Movahedi, A.A., and Bozorgmehr, M.R. (2014). How a protein can remain stable in a solvent with high content of urea: insights from molecular dynamics simulation of Candida Antarctica lipase B in urea : choline chloride deep eutectic solvent. Phys. Chem. Chem. Phys. 16: 14882–14893, https://doi.org/10.1039/c4cp00503a.Search in Google Scholar PubMed
Mourelle-Insua, Á., Lavandera, I., and Gotor-Fernández, V. (2019). A designer natural deep eutectic solvent to recycle the cofactor in alcohol dehydrogenase-catalysed processes. Green Chem. 21: 2946–2951, https://doi.org/10.1039/c9gc00318e.Search in Google Scholar
Nian, B., Cao, C., and Liu, Y. (2019). Lipase and metal chloride hydrate-natural deep eutectic solvents synergistically catalyze amidation reaction via multiple noncovalent bond interactions. ACS Sustain. Chem. Eng. 7: 18174–18184, https://doi.org/10.1021/acssuschemeng.9b05691.Search in Google Scholar
O’Neill, M., Raghuwanshi, V.S., Wendt, R., Wollgarten, M., Hoell, A., and Rademann, K. (2015). Gold nanoparticles in novel green deep eutectic solvents: self-limited growth, self-assembly & catalytic implications. Z. Phys. Chem. 229: 221, https://doi.org/10.1515/zpch-2014-0644.Search in Google Scholar
Paiva, A., Craveiro, R., Aroso, I., Martins, M., Reis, R.L., and Duarte, A.R.C. (2014). Natural deep eutectic solvents – solvents for the 21st century. ACS Sustain. Chem. Eng. 2: 1063–1071, https://doi.org/10.1021/sc500096j.Search in Google Scholar
Pang, K., Hou, Y., Wu, W., Guo, W., Peng, W., and Marsh, K.N. (2012). Efficient separation of phenols from oils via forming deep eutectic solvents. Green Chem. 14: 2398–2401, https://doi.org/10.1039/c2gc35400d.Search in Google Scholar
Pant, P.L. and Shankarling, G.S. (2017). Deep eutectic solvent/lipase: two environmentally benign and recyclable media for efficient synthesis of N-aryl amines. Catal. Lett. 147: 1371–1378, https://doi.org/10.1007/s10562-017-2046-0.Search in Google Scholar
Papadopoulou, A.A., Tzani, A., Polydera, A.C., Katapodis, P., Voutsas, E., Detsi, A., and Stamatis, H. (2018). Green biotransformations catalysed by enzyme-inorganic hybrid nanoflowers in environmentally friendly ionic solvents. Environ. Sci. Pollut. Control Ser. 25: 26707–26714, https://doi.org/10.1007/s11356-017-9271-3.Search in Google Scholar PubMed
Paris, J., Ríos-Lombardía, N., Morís, F., Gröger, H., and González-Sabín, J. (2018). Novel insights into the combination of metal- and biocatalysis: cascade one-pot synthesis of enantiomerically pure biaryl alcohols in deep eutectic solvents. ChemCatChem 10 4417–4423, https://doi.org/10.1002/cctc.201800768.Search in Google Scholar
Pätzold, M., Siebenhaller, S., Kara, S., Liese, A., Syldatk, C., and Holtmann, D. (2019). Deep eutectic solvents as efficient solvents in biocatalysis. Trends Biotechnol. 37: 943–959, https://doi.org/10.1016/j.tibtech.2019.03.007.Search in Google Scholar PubMed
Pavoković, D., Košpić, K., Panić, M., Radojčić Redovniković, I., and Cvjetko Bubalo, M. (2020). Natural deep eutectic solvents are viable solvents for plant cell culture-assisted stereoselective biocatalysis. Process Biochem. 93: 69–76, https://doi.org/10.1016/j.procbio.2020.03.020.Search in Google Scholar
Peng, F., Chen, Q.-S., Li, F.-Z., Ou, X.-Y., Zong, M.-H., and Lou, W.-Y. (2020). Using deep eutectic solvents to improve the biocatalytic reduction of 2-hydroxyacetophenone to (R)-1-phenyl-1,2-ethanediol by Kurthia gibsonii SC0312. Mol. Catal. 484: 110773, https://doi.org/10.1016/j.mcat.2020.110773.Search in Google Scholar
Perna, F.M., Vitale, P., and Capriati, V. (2020). Deep eutectic solvents and their applications as green solvents. Curr. Opin. Green Sustain. Chem. 21: 27–33, https://doi.org/10.1016/j.cogsc.2019.09.004.Search in Google Scholar
Pöhnlein, M., Ulrich, J., Kirschhöfer, F., Nusser, M., Muhle-Goll, C., Kannengiesser, B., Brenner-Weiß, G., Luy, B., Liese, A., Syldatk, C., et al. (2015). Lipase-catalyzed synthesis of glucose-6-O-hexanoate in deep eutectic solvents. Eur. J. Lipid Sci. Technol. 117: 161–166, https://doi.org/10.1002/ejlt.201400459.Search in Google Scholar
Procentese, A., Johnson, E., Orr, V., Garruto Campanile, A., Wood, J.A., Marzocchella, A., and Rehmann, L. (2015). Deep eutectic solvent pretreatment and subsequent saccharification of corncob. Bioresour. Technol. 192: 31–36, https://doi.org/10.1016/j.biortech.2015.05.053.Search in Google Scholar PubMed
Qin, Y.-Z., Li, Y.-M., Zong, M.-H., Wu, H., and Li, N. (2015). Enzyme-catalyzed selective oxidation of 5-hydroxymethylfurfural (HMF) and separation of HMF and 2,5-diformylfuran using deep eutectic solvents. Green Chem. 17: 3718–3722, https://doi.org/10.1039/c5gc00788g.Search in Google Scholar
Sanap, A.K. and Shankarling, G.S. (2014). Eco-friendly and recyclable media for rapid synthesis of tricyanovinylated aromatics using biocatalyst and deep eutectic solvent. Catal. Commun. 49: 58–62, https://doi.org/10.1016/j.catcom.2014.01.031.Search in Google Scholar
Satlewal, A., Agrawal, R., Bhagia, S., Sangoro, J., and Ragauskas, A.J. (2018). Natural deep eutectic solvents for lignocellulosic biomass pretreatment: recent developments, challenges and novel opportunities. Biotechnol. Adv. 36: 2032–2050, https://doi.org/10.1016/j.biotechadv.2018.08.009.Search in Google Scholar PubMed
Shahbaz, K., Mjalli, F.S., Hashim, M.A., and AlNashef, I.M. (2011). Using deep eutectic solvents based on methyl triphenyl phosphunium bromide for the removal of glycerol from palm-oil-based biodiesel. Energy Fuels 25: 2671–2678, https://doi.org/10.1021/ef2004943.Search in Google Scholar
Siebenhaller, S., Gentes, J., Infantes, A., Muhle-Goll, C., Kirschhöfer, F., Brenner-Weiß, G., Ochsenreither, K., and Syldatk, C. (2018). Lipase-Catalyzed synthesis of sugar esters in honey and agave syrup. Front. Chem. 6: 24, https://doi.org/10.3389/fchem.2018.00024.Search in Google Scholar PubMed PubMed Central
Singh, B.S., Lobo, H.R., and Shankarling, G.S. (2012). Choline chloride based eutectic solvents: magical catalytic system for carbon–carbon bond formation in the rapid synthesis of β-hydroxy functionalized derivatives. Catal. Commun. 24: 70–74, https://doi.org/10.1016/j.catcom.2012.03.021.Search in Google Scholar
Singh, B.S., Lobo, H.R., Pinjari, D.V., Jarag, K.J., Pandit, A.B., and Shankarling, G.S. (2013). Ultrasound and deep eutectic solvent (DES): a novel blend of techniques for rapid and energy efficient synthesis of oxazoles. Ultrason. Sonochem. 20: 287–293, https://doi.org/10.1016/j.ultsonch.2012.06.003.Search in Google Scholar PubMed
Smink, D., Juan, A., Schuur, B., and Kersten, S.R.A. (2019). Understanding the role of choline chloride in deep eutectic solvents used for biomass delignification. Ind. Eng. Chem. Res. 58: 16348–16357, https://doi.org/10.1021/acs.iecr.9b03588.Search in Google Scholar
Soares, B., Tavares, D.J.P., Amaral, J.L., Silvestre, A.J.D., Freire, C.S.R., and Coutinho, J.A.P. (2017). Enhanced solubility of lignin monomeric model compounds and technical lignins in aqueous solutions of deep eutectic solvents. ACS Sustain. Chem. Eng. 5: 4056–4065, https://doi.org/10.1021/acssuschemeng.7b00053.Search in Google Scholar
Soh, L. and Eckelman, M.J. (2016). Green solvents in biomass processing. ACS Sustain. Chem. Eng. 4: 5821–5837, https://doi.org/10.1021/acssuschemeng.6b01635.Search in Google Scholar
Taysun, M.B., Sert, E., and Atalay, F.S. (2016). Physical properties of benzyl tri-methyl ammonium chloride based deep eutectic solvents and employment as catalyst. J. Mol. Liq. 223: 845–852, https://doi.org/10.1016/j.molliq.2016.07.148.Search in Google Scholar
Tian, X., Zhang, S., and Zheng, L. (2016). Enzyme-Catalyzed Henry reaction in choline chloride-based deep eutectic solvents. J. Microbiol. Biotechnol. 26: 80–88, https://doi.org/10.4014/jmb.1506.06075.Search in Google Scholar PubMed
Toledo, M.L., Pereira, M.M., Freire, M.G., Silva, J.P.A., Coutinho, J.A.P., and Tavares, A.P.M. (2019). Laccase activation in deep eutectic solvents. ACS Sustain. Chem. Eng. 7: 11806–11814, https://doi.org/10.1021/acssuschemeng.9b02179.Search in Google Scholar
van Osch, D.J.G.P., Zubeir, L.F., van den Bruinhorst, A., Rocha, M.A.A., and Kroon, M.C. (2015). Hydrophobic deep eutectic solvents as water-immiscible extractants. Green Chem. 17: 4518–4521, https://doi.org/10.1039/c5gc01451d.Search in Google Scholar
Vicente, F.A., Bradić, B., Novak, U., and Likozar, B. (2020). α-Chitin dissolution, N-deacetylation and valorization in deep eutectic solvents. Biopolymers: e23351, https://doi.org/10.1002/bip.23351.Search in Google Scholar PubMed
Vigier, K.D.O., Chatel, G., and Jérôme, F. (2015). Contribution of deep eutectic solvents for biomass processing: opportunities, challenges, and limitations. ChemCatChem 7: 1250–1260, https://doi.org/10.1002/cctc.201500134.Search in Google Scholar
Volynets, B., Ein-Mozaffari, F., and Dahman, Y. (2017). Biomass processing into ethanol: pretreatment, enzymatic hydrolysis, fermentation, rheology, and mixing. Green Process. Synth. 1: 1, https://doi.org/10.1515/gps-2016-0017.Search in Google Scholar
Weiz, G., Braun, L., Lopez, R., de María, P.D., and Breccia, J.D. (2016). Enzymatic deglycosylation of flavonoids in deep eutectic solvents-aqueous mixtures: paving the way for sustainable flavonoid chemistry. J. Mol. Catal. B Enzym. 130: 70–73, https://doi.org/10.1016/j.molcatb.2016.04.010.Search in Google Scholar
Xia, Q., Liu, Y., Meng, J., Cheng, W., Chen, W., Liu, S., Liu, Y., Li, J., and Yu, H. (2018). Multiple hydrogen bond coordination in three-constituent deep eutectic solvents enhances lignin fractionation from biomass. Green Chem. 20: 2711–2721, https://doi.org/10.1039/c8gc00900g.Search in Google Scholar
Xu, G.-C., Ding, J.-C., Han, R.-Z., Dong, J.-J., and Ni, Y. (2016a). Enhancing cellulose accessibility of corn stover by deep eutectic solvent pretreatment for butanol fermentation. Bioresour. Technol. 203: 364–369, https://doi.org/10.1016/j.biortech.2015.11.002.Search in Google Scholar PubMed
Xu, P., Zheng, G.-W., Du, P.-X., Zong, M.-H., and Lou, W.-Y. (2016b). Whole-cell biocatalytic processes with ionic liquids. ACS Sustain. Chem. Eng. 4: 371–386, https://doi.org/10.1021/acssuschemeng.5b00965.Search in Google Scholar
Xu, P., Zheng, G.-W., Zong, M.-H., Li, N., and Lou, W.-Y. (2017). Recent progress on deep eutectic solvents in biocatalysis. Bioresour. Bioprocess. 4: 34–34, https://doi.org/10.1186/s40643-017-0165-5.Search in Google Scholar PubMed PubMed Central
Xu, H., Peng, J., Kong, Y., Liu, Y., Su, Z., Li, B., Song, X., Liu, S., and Tian, W. (2020). Key process parameters for deep eutectic solvents pretreatment of lignocellulosic biomass materials: a review. Bioresour. Technol. 310: 123416, https://doi.org/10.1016/j.biortech.2020.123416.Search in Google Scholar PubMed
Yang, Z., Wen, Q. (2015). Deep eutectic solvents as a new reaction medium for biotransformations. Ionic Liquid-Based Surfactant Sci.: 517–531, https://doi.org/10.1002/9781118854501.ch25.Search in Google Scholar
Yang, T.-X., Zhao, L.-Q., Wang, J., Song, G.-L., Liu, H.-M., Cheng, H., and Yang, Z. (2017). Improving whole-cell biocatalysis by addition of deep eutectic solvents and natural deep eutectic solvents. ACS Sustain. Chem. Eng. 5: 5713–5722, https://doi.org/10.1021/acssuschemeng.7b00285.Search in Google Scholar
Yiin, C.L., Quitain, A.T., Yusup, S., Sasaki, M., Uemura, Y., and Kida, T. (2016). Characterization of natural low transition temperature mixtures (LTTMs): green solvents for biomass delignification. Bioresour. Technol. 199: 258–264, https://doi.org/10.1016/j.biortech.2015.07.103.Search in Google Scholar PubMed
Yoo, C.G., Pu, Y., and Ragauskas, A.J. (2017). Ionic liquids: promising green solvents for lignocellulosic biomass utilization. Curr. Opin. Green Sustain. Chem. 5: 5–11, https://doi.org/10.1016/j.cogsc.2017.03.003.Search in Google Scholar
Yuan, Y., Hong, S., Lian, H., Zhang, K., and Liimatainen, H. (2020). Comparison of acidic deep eutectic solvents in production of chitin nanocrystals. Carbohydr. Polym. 236: 116095, https://doi.org/10.1016/j.carbpol.2020.116095.Search in Google Scholar PubMed
Zang, Y.-Y., Yang, X., Chen, Z.-G., and Wu, T. (2020). One-pot preparation of quercetin using natural deep eutectic solvents. Process Biochem. 89: 193–198, https://doi.org/10.1016/j.procbio.2019.10.019.Search in Google Scholar
Zeng, C.-X., Qi, S.-J., Xin, R.-P., Yang, B., and Wang, Y.-H. (2015). Enzymatic selective synthesis of 1,3-DAG based on deep eutectic solvent acting as substrate and solvent. Bioproc. Biosyst. Eng. 38: 2053–2061, https://doi.org/10.1007/s00449-015-1445-0.Search in Google Scholar PubMed
Zhang, Q., De Oliveira Vigier, K., Royer, S., and Jérôme, F. (2012). Deep eutectic solvents: syntheses, properties and applications. Chem. Soc. Rev. 41: 7108–7146, https://doi.org/10.1039/c2cs35178a.Search in Google Scholar PubMed
Zhang, Y., Ji, X., and Lu, X. (2015). Chapter 3-Choline-based deep eutectic solvents for mitigating carbon dioxide emissions. In: Shi, F. and Morreale, B. (Eds.), Novel materials for carbon dioxide mitigation technology. Amsterdam: Elsevier, pp. 87–116.10.1016/B978-0-444-63259-3.00003-3Search in Google Scholar
Zhang, C.-W., Xia, S.-Q., and Ma, P.-S. (2016). Facile pretreatment of lignocellulosic biomass using deep eutectic solvents. Bioresour. Technol. 219: 1–5, https://doi.org/10.1016/j.biortech.2016.07.026.Search in Google Scholar PubMed
Zhao, H., Baker, G.A., and Holmes, S. (2011a). New eutectic ionic liquids for lipase activation and enzymatic preparation of biodiesel. Org. Biomol. Chem. 9: 1908–1916, https://doi.org/10.1039/c0ob01011a.Search in Google Scholar PubMed PubMed Central
Zhao, H., Baker, G.A., and Holmes, S. (2011b). Protease activation in glycerol-based deep eutectic solvents. J. Mol. Catal. B Enzym. 72: 163–167, https://doi.org/10.1016/j.molcatb.2011.05.015.Search in Google Scholar PubMed PubMed Central
Zhao, H., Zhang, C., and Crittle, T.D. (2013). Choline-based deep eutectic solvents for enzymatic preparation of biodiesel from soybean oil. J. Mol. Catal. B Enzym. 85–86: 243–247, https://doi.org/10.1016/j.molcatb.2012.09.003.Search in Google Scholar
Zulkefli, S., Abdulmalek, E., and Abdul Rahman, M.B. (2017). Pretreatment of oil palm trunk in deep eutectic solvent and optimization of enzymatic hydrolysis of pretreated oil palm trunk. Renew. Energy 107: 36–41, https://doi.org/10.1016/j.renene.2017.01.037.Search in Google Scholar
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