Global evolution of research on autohydrolysis (hydrothermal) pretreatment as a green technology for biorefineries: A bibliometric analysis

Yuxin Yu; Wenhui Pei; Xiaoxue Zhao; Aldo Joao Cárdenas-Oscanoa; Caoxing Huang

doi:10.1016/j.jobab.2024.12.002

Volume 10 Issue 1

Feb. 2025

Turn off MathJax

Article Contents

Article Navigation > Journal of Bioresources and Bioproducts > 2025 > 10(1): 92-110

Yuxin Yu, Wenhui Pei, Xiaoxue Zhao, Aldo Joao Cárdenas-Oscanoa, Caoxing Huang. Global evolution of research on autohydrolysis (hydrothermal) pretreatment as a green technology for biorefineries: A bibliometric analysis[J]. Journal of Bioresources and Bioproducts, 2025, 10(1): 92-110. doi: 10.1016/j.jobab.2024.12.002

Citation:

Yuxin Yu, Wenhui Pei, Xiaoxue Zhao, Aldo Joao Cárdenas-Oscanoa, Caoxing Huang. Global evolution of research on autohydrolysis (hydrothermal) pretreatment as a green technology for biorefineries: A bibliometric analysis[J]. Journal of Bioresources and Bioproducts, 2025, 10(1): 92-110. doi: 10.1016/j.jobab.2024.12.002

Citation:

Yuxin Yu, Wenhui Pei, Xiaoxue Zhao, Aldo Joao Cárdenas-Oscanoa, Caoxing Huang. Global evolution of research on autohydrolysis (hydrothermal) pretreatment as a green technology for biorefineries: A bibliometric analysis[J]. Journal of Bioresources and Bioproducts, 2025, 10(1): 92-110. doi: 10.1016/j.jobab.2024.12.002

PDF( 3890 KB)

Global evolution of research on autohydrolysis (hydrothermal) pretreatment as a green technology for biorefineries: A bibliometric analysis

doi: 10.1016/j.jobab.2024.12.002

a. Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China;
b. Forest Industry Department, Faculty of Forest Sciences, Universidad Nacional Agraria La Molina, Lima 15024, Perú

Funds:

This work was financially supported by Natural Science Foundation of Jiangsu Province (No. BK20220106).

Available Online: 2025-02-21
Publish Date: 2024-12-15

Abstract

Abstract

Based on 6 403 research articles in the Web of Science database from 2000 to 2023, information visualization technology is employed to analyze the literature year distribution, keyword co-occurrence and research hot spots, author cooperation network, institutional and national cooperation network, published journals, and co-cited literature in the middle of hydrothermal pretreatment. Our results show that the number of applied research publications related to hydrothermal pretreatment has increased every year in the past two decades. Among these publications, China (36.5%) is the most active country in the world, followed by the United States (14.6%) and Japan (8.2%), with increasing global cooperation. The Chinese Academy of Sciences ranks first among the institutions in the light of total publication output (245 articles, accounting for 3.82%). Among 955 journals, Bioresource Technology is cited the most frequently. The study is centered on the enhancement and potential evolution of lignocellulosic biomass raw materials via hydrothermal pretreatment for subsequent bioenergy transformation. Concurrently, the domain of hydrothermal pretreatment has progressively become more cross-disciplinary, intertwining with the sectors of microbial populations and genomes.
- Hydrothermal pretreatment,
- Lignocellulosic biomass,
- Bio-refinery,
- Biblimetrics analysis

FullText(HTML)

References(137)

References

[1]	Acharya, S., Liyanage, S., Parajuli, P., Rumi, S.S., Shamshina, J.L., Abidi, N., 2021. Utilization of cellulose to its full potential: a review on cellulose dissolution, regeneration, and applications. Polymers (Basel)13, 4344.
[2]	Agbor, V.B., Cicek, N., Sparling, R., Berlin, A., Levin, D.B., 2011. Biomass pretreatment: fundamentals toward application. Biotechnol. Adv.29, 675-685.
[3]	Ahmad, F., Silva, E.L., Varesche, M.B.A., 2018. Hydrothermal processing of biomass for anaerobic digestion-A review. Renew. Sustain. Energy Rev.98, 108-124.
[4]	Alcazar-Ruiz, A., Villardon, A., Dorado, F., Sanchez-Silva, L., 2023. Hydrothermal carbonization coupled with fast pyrolysis of almond shells: valorization and production of valuable chemicals. Waste Manag. 169, 112-124.
[5]	Álvaro, A.G., Palomar, C.R., Redondo, D.H., Torre, R.M., de Godos Crespo, I., 2023. Simultaneous production of biogas and volatile fatty acids through anaerobic digestion using cereal straw as substrate. Environ. Technol. Innov.31, 103215.
[6]	Alvira, P., Tomás-Pejó, E., Ballesteros, M., Negro, M.J., 2010. Pretreatment technologies for an efficient bioethanol production process based on enzymatic hydrolysis: a review. Bioresour. Technol.101, 4851-4861.
[7]	Aria, M., Cuccurullo, C., 2017. Bibliometrix: an R-tool for comprehensive science mapping analysis. J. Informetr.11, 959-975.
[8]	Arpia, A.A., Chen, W.H., Lam, S.S., Rousset, P., de Luna, M.D.G., 2021. Sustainable biofuel and bioenergy production from biomass waste residues using microwave-assisted heating: a comprehensive review. Chem. Eng. J.403, 126233.
[9]	Arun, J., Varshini, P., Prithvinath, P.K., Priyadarshini, V., Gopinath, K.P., 2018. Enrichment of bio-oil after hydrothermal liquefaction (HTL) of microalgae C. vulgaris grown in wastewater: bio-char and post HTL wastewater utilization studies. Bioresour. Technol.261, 182-187.
[10]	Ashokkumar, V., Chandramughi, V.P., Kumar, G., Ngamcharussrivichai, C., Piechota, G., Igliński, B., Kothari, R., Chen, W.H., 2024. Advancements in lignocellulosic biomass: a critical appraisal of fourth-generation biofuels and value-added bioproduct. Fuel365, 130751.
[11]	Azmoon, P., Farhadian, M., Pendashteh, A., Navarchian, A.H., 2024. Synergistic effect of adsorption and photocatalytic degradation of oilfield-produced water by electrospun photocatalytic fibers of Polystyrene/Nanorod-Graphitic carbon nitride. J. Environ. Sci.141, 287-303.
[12]	Banu Jamaldheen, S., Kurade, M.B., Basak, B., Yoo, C.G., Oh, K.K., Jeon, B.H., Kim, T.H., 2022. A review on physico-chemical delignification as a pretreatment of lignocellulosic biomass for enhanced bioconversion. Bioresour. Technol.346, 126591.
[13]	Batista, G., Souza, R.B.A., Pratto, B., Dos Santos-Rocha, M.S.R., Cruz, A.J.G., 2019. Effect of severity factor on the hydrothermal pretreatment of sugarcane straw. Bioresour. Technol.275, 321-327.
[14]	Bhutto, A.W., Qureshi, K., Harijan, K., Abro, R., Abbas, T., Bazmi, A.A., Karim, S., Yu, G.R., 2017. Insight into progress in pre-treatment of lignocellulosic biomass. Energy122, 724-745.
[15]	Bornmann, L., Leydesdorff, L., 2014. Scientometrics in a changing research landscape: bibliometrics has become an integral part of research quality evaluation and has been changing the practice of research. EMBO Rep.15, 1228-1232.
[16]	Broadus, R.N., 1987. Toward a definition of “bibliometrics”. Scientometrics12, 373-379.
[17]	Carvalheiro, F., Duarte, L.C., Gírio, F., Moniz, P., 2016. Hydrothermal/liquid hot water pretreatment (autohydrolysis). Biomass Fractionation Technologies for a Lignocellulosic Feedstock Based Biorefinery. Amsterdam: Elsevier, 315-347.
[18]	Castañeda, K., Sánchez, O., Herrera, R.F., Mejía, G., 2022. Highway planning trends: a bibliometric analysis. Sustainability14, 5544.
[19]	Champadang, O., Boonsombuti, A., Luengnaruemitchai, A., 2022. Enhanced enzymatic digestibility of water lettuce by liquid hot water pretreatment. Bioresour. Technol. Rep.18, 101100.
[20]	Chen, C.M., 2006. CiteSpace II: detecting and visualizing emerging trends and transient patterns in scientific literature. J. Am. Soc. Inf. Sci.57, 359-377.
[21]	Chen, C.M., Leydesdorff, L., 2014. Patterns of connections and movements in dual-map overlays: a new method of publication portfolio analysis. J. Assoc. Inf. Sci. Technol.65, 334-351.
[22]	Chen, W.H., Nižetić, S., Sirohi, R., Huang, Z.H., Luque, R., M Papadopoulos, A., Sakthivel, R., Phuong Nguyen, X., Hoang, A.T., 2022. Liquid hot water as sustainable biomass pretreatment technique for bioenergy production: a review. Bioresour. Technol.344, 126207.
[23]	Cheng, F., 2018. Hydrothermal Liquefaction of Microalgae in Batch and Continuous Flow Reactors. Las Cruces: New Mexico State University.
[24]	Cherwoo, L., Gupta, I., Flora, G., Verma, R., Kapil, M., Arya, S.K., Ravindran, B., Khoo, K.S., Bhatia, S.K., Chang, S.W., Ngamcharussrivichai, C., Ashokkumar, V., 2023. Biofuels an alternative to traditional fossil fuels: a comprehensive review. Sustain. Energy Technol. Assess.60, 103503.
[25]	Chi, P.S., Glänzel, W., 2017. An empirical investigation of the associations among usage, scientific collaboration and citation impact. Scientometrics112, 403-412.
[26]	Cobo, M.J., López-Herrera, A.G., Herrera-Viedma, E., Herrera, F., 2011. An approach for detecting, quantifying, and visualizing the evolution of a research field: a practical application to the fuzzy sets theory field. J. Informetr.5, 146-166.
[27]	da Fonseca, Y.A., Silva, N.C.S., de Camargos, A.B., de Queiroz Silva, S., Wandurraga, H.J.L., Gurgel, L.V.A., Baêta, B.E.L., 2021. Influence of hydrothermal pretreatment conditions, typology of anaerobic digestion system, and microbial profile in the production of volatile fatty acids from olive mill solid waste. J. Environ. Chem. Eng.9, 105055.
[28]	Dalal, R., Sangwan, A., Khari, M., 2023. The bibliometrics assessment of opportunistic network protocols & simulation tools. Telematics Inform. Rep.11, 100082.
[29]	Das, N., Jena, P.K., Padhi, D., Kumar Mohanty, M., Sahoo, G., 2023. A comprehensive review of characterization, pretreatment and its applications on different lignocellulosic biomass for bioethanol production. Biomass Convers. Biorefin.13, 1503-1527.
[30]	Dávila, I., Gordobil, O., Labidi, J., Gullón, P., 2016. Assessment of suitability of vine shoots for hemicellulosic oligosaccharides production through aqueous processing. Bioresour. Technol.211, 636-644.
[31]	de Sá, L.R.V., de Oliveira Faber, M., da Silva, A.S., Cammarota, M.C., Ferreira-Leitão, V.S., 2020. Biohydrogen production using xylose or xylooligosaccharides derived from sugarcane bagasse obtained by hydrothermal and acid pretreatments. Renew. Energy146, 2408-2415.
[32]	Donthu, N., Kumar, S., Mukherjee, D., Pandey, N., Lim, W.M., 2021. How to conduct a bibliometric analysis: an overview and guidelines. J. Bus. Res.133, 285-296.
[33]	Du, B.Y., Li, W.J., Chai, L.F., Li, W., Wang, X., Chen, X.H., Zhou, J.H., Sun, R.C., 2023. Preparation of versatile lignin-based adsorbent for the removal of organic dyes and its application in wound healing. J. Mol. Liq.377, 121566.
[34]	Egghe, L., Rousseau, R., 1990. Introduction to informetrics. Quantitative methods in library, Documentation and Information Science. Amsterdam: Elsevier.
[35]	Elliott, D.C., Biller, P., Ross, A.B., Schmidt, A.J., Jones, S.B., 2015. Hydrothermal liquefaction of biomass: developments from batch to continuous process. Bioresour. Technol.178, 147-156.
[36]	Ercan, B., Alper, K., Ucar, S., Karagoz, S., 2023. Comparative studies of hydrochars and biochars produced from lignocellulosic biomass via hydrothermal carbonization, torrefaction and pyrolysis. J. Energy Inst.109, 101298.
[37]	Eswari, A.P., Ravi, Y.K., Kavitha, S., Banu, J.R., 2023. Recent insight into anaerobic digestion of lignocellulosic biomass for cost effective bioenergy generation. E Prime Adv. Electr. Eng. Electron. Energy3, 100119.
[38]	Ewanick, S., Bura, R., 2010. Hydrothermal pretreatment of lignocellulosic biomass. Bioalcohol Production. Amsterdam: Elsevier, 3-23.
[39]	Fan, Y.J., Hornung, U., Dahmen, N., 2022. Hydrothermal liquefaction of sewage sludge for biofuel application: a review on fundamentals, current challenges and strategies. Biomass Bioenergy165, 106570.
[40]	Fang, L.Y., Su, Y., Wang, P., Lai, C.H., Huang, C.X., Ling, Z., Yong, Q., 2022. Co-production of xylooligosaccharides and glucose from birch sawdust by hot water pretreatment and enzymatic hydrolysis. Bioresour. Technol.348, 126795.
[41]	Fang, Y., Yin, J., Wu, B.H., 2018. Climate change and tourism: a scientometric analysis usingCiteSpace. J. Sustain. Tour.26, 108-126.
[42]	Farghali, M., Shimahata, A., Mohamed, I.M.A., Iwasaki, M., Lu, J.X., Ihara, I., Umetsu, K., 2022. Integrating anaerobic digestion with hydrothermal pretreatment for bioenergy production: waste valorization of plastic containing food waste and rice husk. Biochem. Eng. J.186, 108546.
[43]	Flórez-Fernández, N., Rodríguez-Coello, A., Latire, T., Bourgougnon, N., Torres, M.D., Buján, M., Muíños, A., Muiños, A., Meijide-Faílde, R., Blanco, F.J., Vaamonde-García, C., Domínguez, H., 2023. Anti-inflammatory potential of ulvan. Int. J. Biol. Macromol.253, 126936.
[44]	Gandam, P.K., Chinta, M.L., Pabbathi, N.P.P., Baadhe, R.R., Sharma, M., Thakur, V.K., Sharma, G.D., Ranjitha, J., Gupta, V.K., 2022. Second-generation bioethanol production from corncob-A comprehensive review on pretreatment and bioconversion strategies, including techno-economic and lifecycle perspective. Ind. Crops Prod.186, 115245.
[45]	Gao, D.H., Haarmeyer, C., Balan, V., Whitehead, T.A., Dale, B.E., Chundawat, S.P., 2014. Lignin triggers irreversible cellulase loss during pretreated lignocellulosic biomass saccharification. Biotechnol. Biofuels7, 175.
[46]	Gökkaya, D.S., Saglam, M., Yuksel, M., Ballice, L., 2016. Hydrothermal gasification of xylose: effects of reaction temperature, pressure, and K2CO₃ as a catalyst on product distribution. Biomass Bioenergy91, 26-36.
[47]	Gollakota, A.R.K., Kishore, N., Gu, S., 2018. A review on hydrothermal liquefaction of biomass. Renew. Sustain. Energy Rev.81, 1378-1392.
[48]	He, C.J., Hu, J.G., Shen, F., Huang, M., Zhao, L., Zou, J.M., Tian, D., Jiang, Q., Zeng, Y.M., 2022. Tuning hydrothermal pretreatment severity of wheat straw to match energy application scenarios. Ind. Crops Prod.176, 114326.
[49]	Hirsch, J.E., 2005. An index to quantify an individual's scientific research output. Proc. Natl. Acad. Sci. USA102, 16569-16572.
[50]	Hoang, A.T., Nguyen, X.P., Duong, X.Q., Ağbulut, Ü., Len, C., Nguyen, P.Q.P., Kchaou, M., Chen, W.H., 2023. Steam explosion as sustainable biomass pretreatment technique for biofuel production: characteristics and challenges. Bioresour. Technol.385, 129398.
[51]	Jacsó, P., 2011. The h-index, h-core citation rate and the bibliometric profile of the Web of Science database in three configurations. Online Inf. Rev.35, 821-833.
[52]	Jönsson, L.J., Martín, C., 2016. Pretreatment of lignocellulose: formation of inhibitory by-products and strategies for minimizing their effects. Bioresour. Technol.199, 103-112.
[53]	Kumar, M., Olajire Oyedun, A., Kumar, A., 2018. A review on the current status of various hydrothermal technologies on biomass feedstock. Renew. Sustain. Energy Rev.81, 1742-1770.
[54]	Kundu, R., Kunnoth, B., Pilli, S., Polisetty, V.R., Tyagi, R.D., 2023. Biochar symbiosis in anaerobic digestion to enhance biogas production: a comprehensive review. J. Environ. Manage.344, 118743.
[55]	Lachos-Perez, D., César Torres-Mayanga, P., Abaide, E.R., Zabot, G.L., De Castilhos, F., 2022. Hydrothermal carbonization and Liquefaction: differences, progress, challenges, and opportunities. Bioresour. Technol.343, 126084.
[56]	Lan, K., Xu, Y.L., Kim, H., Ham, C., Kelley, S.S., Park, S., 2021. Techno-economic analysis of producing xylo-oligosaccharides and cellulose microfibers from lignocellulosic biomass. Bioresour. Technol.340, 125726.
[57]	Lang, S., Zhang, S.Y., Cao, Z.Y., Yang, J.F., Zhou, Y., Liu, S.M., Xu, J.Q., Yang, C.K., 2023. Improvement of hydrochar/biochar pellets prepared from cotton stalk by hydrothermal pretreatment process. J. Anal. Appl. Pyrolysis176, 106263.
[58]	Laser, M.S., 2001. Hydrothermal Pretreatment of Cellulosic Biomass for Bioconversion to Ethanol. Hanover: Dartmouth College.
[59]	Lee, K.T., Chen, W.H., Sarles, P., Park, Y.K., Ok, Y.S., 2022. Recover energy and materials from agricultural waste via thermochemical conversion. One Earth5, 1200-1204.
[60]	Leng, L.J., Yuan, X.Z., Huang, H.J., Wang, H., Wu, Z.B., Fu, L.H., Peng, X., Chen, X.H., Zeng, G.M., 2015. Characterization and application of bio-chars from liquefaction of microalgae, lignocellulosic biomass and sewage sludge. Fuel Process. Technol.129, 8-14.
[61]	Li, B.Y., Tan, W., Wang, Z.C., Zhou, H.X., Zou, J.L., Li, Y., Yoshida, S., Zhou, Y.D., 2023a. Progress and prospects of gene therapy in ophthalmology from 2000 to 2022: a bibliometric analysis. Heliyon9, e18228.
[62]	Li, M., Wang, Y., Shen, Z.F., Chi, M.S., Lv, C., Li, C.Y., Bai, L., Thabet, H.K., El-Bahy, S.M., Ibrahim, M.M., Chuah, L.F., Show, P.L., Zhao, X.L., 2022. Investigation on the evolution of hydrothermal biochar. Chemosphere307, 135774.
[63]	Li, Q.W., Long, R.Y., Chen, H., Chen, F.Y., Wang, J.Q., 2020. Visualized analysis of global green buildings: development, barriers and future directions. J. Clean. Prod.245, 118775.
[64]	Li, Y., Du, Q., Zhang, J.S., Jiang, Y., Zhou, J.J., Ye, Z.N., 2023b. Visualizing the intellectual landscape and evolution of transportation system resilience: a bibliometric analysis in CiteSpace. Dev. Built Environ.14, 100149.
[65]	Liu, F.H., Yu, C.H., Chang, Y.C., 2022. Bibliometric analysis of articles published in journal of dental sciences from 2009 to 2020. J. Dent. Sci.17, 642-646.
[66]	Liu, W., Wang, Q., Xu, W.Z., Xu, G.H., Li, W.P., Tang, L.N., Liu, K., 2024. Applications of lignin molecules in energy storage devices. J. For. Eng.9, 1-20.
[67]	Liu, X.Z., Zhang, J.S., Guo, C., 2013. Full-text citation analysis: a new method to enhance scholarly networks. J. Am. Soc. Inf. Sci. Technol.64, 1852-1863.
[68]	Lu, H.S., Liu, S.Y., Zhang, M.H., Meng, F.M., Shi, X.F., Yan, L., 2016. Investigation of the strengthening process for liquid hot water pretreatments. Energy Fuels30, 1103-1108.
[69]	Lü, H.S., Zhou, J.Y., Liu, J.T., Lü, C.L., Lian, F., Li, Y.H., 2019. Optimization of hydrothermal pretreatment for co-utilization of xylose and glucose of cassava anaerobic residue for producing ethanol. Chin. J. Chem. Eng.27, 920-927.
[70]	Lu, Y., Sun, Y.Y., Zhang, L., Zuo, X.Y., Li, X.J., Yuan, H.R., 2023. Substance bioconversion, hydrolases activity, and metagenomic analysis to unravel the enhanced biomethanation of corn stover with urea-hydrothermal pretreatment. J. Environ. Manage.333, 117466.
[71]	Lyu, P.H., Liu, X.L., Yao, T., 2023. A bibliometric analysis of literature on bibliometrics in recent half-century. J. Inf. Sci.: 01655515231191233.
[72]	Ma, X.J., Zhang, H., Chen, Q.Y., Huang, H., Cheng, H.T., Huang, L.L., Chen, L.H., Ni, Y.H., Cao, S.L., 2020. Comparison of single-stage and two-stage hydrothermal pretreatments for improving hemicellulose separation from bamboo chips. Wood Sci. Technol.54, 547-557.
[73]	Magina, S., Marques, S., Gírio, F., Lourenço, A., Barros-Timmons, A., Evtuguin, D.V., 2024. Chemical composition and structural features of cellolignin from steam explosion followed by enzymatic hydrolysis of Eucalyptus globulus bark. Ind. Crops Prod.211, 118217.
[74]	Mahmoodi, P., Karimi, K., Taherzadeh, M.J., 2018. Hydrothermal processing as pretreatment for efficient production of ethanol and biogas from municipal solid waste. Bioresour. Technol.261, 166-175.
[75]	Mathimani, T., Mallick, N., 2019. A review on the hydrothermal processing of microalgal biomass to bio-oil - Knowledge gaps and recent advances. J. Clean. Prod.217, 69-84.
[76]	McCance, K.R., Suarez, A., McAlexander, S.L., Davis, G., Blanchard, M.R., Venditti, R.A., 2021. Modeling a biorefinery: converting pineapple waste to bioproducts and biofuel. J. Chem. Educ.98, 2047-2054.
[77]	Morales, A., Labidi, J., Gullón, P., 2021. Hydrothermal treatments of walnut shells: a potential pretreatment for subsequent product obtaining. Sci. Total Environ.764, 142800.
[78]	Mosier, N., Wyman, C., Dale, B., Elander, R., Lee, Y.Y., Holtzapple, M., Ladisch, M., 2005. Features of promising technologies for pretreatment of lignocellulosic biomass. Bioresour. Technol.96, 673-686.
[79]	Ninkov, A., Frank, J.R., Maggio, L.A., 2022. Bibliometrics: methods for studying academic publishing. Perspect. Med. Educ.11, 173-176.
[80]	Nitsos, C.K., Matis, K.A., Triantafyllidis, K.S., 2013. Optimization of hydrothermal pretreatment of lignocellulosic biomass in the bioethanol production process. ChemSusChem6, 110-122.
[81]	Okolie, J.A., Nanda, S., Dalai, A.K., Kozinski, J.A., 2021. Chemistry and specialty industrial applications of lignocellulosic biomass. Waste Biomass Valorization12, 2145-2169.
[82]	Peters, H.P.F., van Raan, A.F.J., 1993. Co-word-based science maps of chemical engineering. part I: representations by direct multidimensional scaling. Res. Policy22, 23-45.
[83]	Prado, J.M., Lachos-Perez, D., Forster-Carneiro, T., Rostagno, M., 2016. Sub- and supercritical water hydrolysis of agricultural and food industry residues for the production of fermentable sugars: a review. Food Bioprod. Process.98, 95-123.
[84]	Radhakrishnan, S., Erbis, S., Isaacs, J.A., Kamarthi, S., 2017. Novel keyword co-occurrence network-based methods to foster systematic reviews of scientific literature. PLoS One12, e0172778.
[85]	Rau, P., Bourrel, L., Labat, D., Melo, P., Dewitte, B., Frappart, F., Felipe, O., 2017. Regionalization of rainfall over the Peruvian Pacific slope and coast. Int. J. Climatol. 37, 143-158.
[86]	Rodionova, M.V., Bozieva, A.M., Zharmukhamedov, S.K., Leong, Y.K., Lan, J.C.W., Veziroglu, A., Allakhverdiev, S.I., 2022. A comprehensive review on lignocellulosic biomass biorefinery for sustainable biofuel production. Int. J. Hydrogen Energy47, 1481-1498.
[87]	Roldan-Valadez, E., Salazar-Ruiz, S.Y., Ibarra-Contreras, R., Rios, C., 2019. Current concepts on bibliometrics: a brief review about impact factor, Eigenfactor score, CiteScore, SCImago Journal Rank, Source-Normalised Impact per Paper, H-index, and alternative metrics. Ir. J. Med. Sci.188, 939-951.
[88]	Ruiz, H.A., Conrad, M., Sun, S.N., Sanchez, A., Rocha, G.J.M., Romaní, A., Castro, E., Torres, A., Rodríguez-Jasso, R.M., Andrade, L.P., Smirnova, I., Sun, R.C., Meyer, A.S., 2020. Engineering aspects of hydrothermal pretreatment: from batch to continuous operation, scale-up and pilot reactor under biorefinery concept. Bioresour. Technol.299, 122685.
[89]	Ruiz, H.A., Rodríguez-Jasso, R.M., Fernandes, B.D., Vicente, A.A., Teixeira, J.A., 2013. Hydrothermal processing, as an alternative for upgrading agriculture residues and marine biomass according to the biorefinery concept: a review. Renew. Sustain. Energy Rev.21, 35-51.
[90]	Saha, B.C., 2003. Hemicellulose bioconversion. J. Ind. Microbiol. Biotechnol.30, 279-291.
[91]	Saravanakumar, A., Sudha, M.R., Chen, W.H., Pradeshwaran, V., Ashokkumar, V., Selvarajoo, A., 2023. Biomethane production as a green energy source from anaerobic digestion of municipal solid waste: a state-of-the-art review. Biocatal. Agric. Biotechnol.53, 102866.
[92]	Sarker, T.R., Pattnaik, F., Nanda, S., Dalai, A.K., Meda, V., Naik, S., 2021. Hydrothermal pretreatment technologies for lignocellulosic biomass: a review of steam explosion and subcritical water hydrolysis. Chemosphere284, 131372.
[93]	Sevilla, M., Fuertes, A.B., 2009. The production of carbon materials by hydrothermal carbonization of cellulose. Carbon N Y47, 2281-2289.
[94]	Shangdiar, S., Lin, Y.C., Ponnusamy, V.K., Wu, T.Y., 2022. Pretreatment of lignocellulosic biomass from sugar bagasse under microwave assisted dilute acid hydrolysis for biobutanol production. Bioresour. Technol.361, 127724.
[95]	Shinde, S.D., Meng, X.Z., Kumar, R., Ragauskas, A.J., 2018. Recent advances in understanding the pseudo-lignin formation in a lignocellulosic biorefinery. Green Chem. 20, 2192-2205.
[96]	Sillet, A., 2013. Definition and use of bibliometrics in research. Soins, 29-30.
[97]	Singh, A., Tsai, M.L., Chen, C.W., Rani Singhania, R., Kumar Patel, A., Tambat, V., Dong, C.D., 2023a. Role of hydrothermal pretreatment towards sustainable biorefinery. Bioresour. Technol.367, 128271.
[98]	Singh, R., Kumar, R., Sarangi, P.K., Kovalev, A.A., Vivekanand, V., 2023b. Effect of physical and thermal pretreatment of lignocellulosic biomass on biohydrogen production by thermochemical route: a critical review. Bioresour. Technol.369, 128458.
[99]	Singhvi, M.S., Gokhale, D.V., 2019. Lignocellulosic biomass: hurdles and challenges in its valorization. Appl. Microbiol. Biotechnol.103, 9305-9320.
[100]	Sun, D., Lv, Z.W., Rao, J., Tian, R., Sun, S.N., Peng, F., 2022. Effects of hydrothermal pretreatment on the dissolution and structural evolution of hemicelluloses and lignin: a review. Carbohydr. Polym.281, 119050.
[101]	Sun, H.N., Lee, P.C., 2010. Maping knowledge structure by keyword co-occurrence: a first look at journal papers in technology foresight. Scientometrics85, 65-79.
[102]	Sun, Q., Chen, W.J., Pang, B., Sun, Z.H., Lam, S.S., Sonne, C., Yuan, T.Q., 2021. Ultrastructural change in lignocellulosic biomass during hydrothermal pretreatment. Bioresour. Technol.341, 125807.
[103]	Sun, S.F., Wan, H.F., Zhao, X., Gao, C., Xiao, L.P., Sun, R.C., 2023. Facile construction of lignin-based network composite hydrogel for efficient adsorption of methylene blue from wastewater. Int. J. Biol. Macromol.253, 126688.
[104]	Sun, S.N., Sun, S.L., Cao, X.F., Sun, R.C., 2016. The role of pretreatment in improving the enzymatic hydrolysis of lignocellulosic materials. Bioresour. Technol.199, 49-58.
[105]	Tan, H.T., Lee, K.T., 2012. Understanding the impact of ionic liquid pretreatment on biomass and enzymatic hydrolysis. Chem. Eng. J.183, 448-458.
[106]	Tang, Y., Chandra, R.P., Sokhansanj, S., Saddler, J.N., 2018. Influence of steam explosion processes on the durability and enzymatic digestibility of wood pellets. Fuel211, 87-94.
[107]	Tomaszewski, R., 2023. Visibility, impact, and applications of bibliometric software tools through citation analysis. Scientometrics128, 4007-4028.
[108]	Tooyserkani, Z., Kumar, L., Sokhansanj, S., Saddler, J., Bi, X.T., Lim, C.J., Lau, A., Melin, S., 2013. SO₂-catalyzed steam pretreatment enhances the strength and stability of softwood pellets. Bioresour. Technol.130, 59-68.
[109]	Torres-Mayanga, P.C., Lachos-Perez, D., Mudhoo, A., Kumar, S., Brown, A.B., Tyufekchiev, M., Dragone, G., Mussatto, S.I., Rostagno, M.A., Timko, M., Forster-Carneiro, T., 2019. Production of biofuel precursors and value-added chemicals from hydrolysates resulting from hydrothermal processing of biomass: a review. Biomass Bioenergy130, 105397.
[110]	Vaamonde-García, C., Capelo-Mera, E., Flórez-Fernández, N., Torres, M.D., Rivas-Murias, B., Mejide-Faílde, R., Blanco, F.J., Domínguez, H., 2022. In vitro study of the therapeutic potential of brown crude fucoidans in osteoarthritis treatment. Int. J. Mol. Sci.23, 14236.
[111]	van Eck, N.J., Waltman, L., 2010. Software survey: vOSviewer, a computer program for bibliometric mapping. Scientometrics84, 523-538.
[112]	Wang, D., Shen, F., Yang, G., Zhang, Y.Z., Deng, S.H., Zhang, J., Zeng, Y.M., Luo, T., Mei, Z.L., 2018a. Can hydrothermal pretreatment improve anaerobic digestion for biogas from lignocellulosic biomass?Bioresour. Technol.249, 117-124.
[113]	Wang, L.P., Chang, Y.Z., Zhang, X.J., Yang, F., Li, Y., Yang, X.R., Dong, S.G., 2020. Hydrothermal co-carbonization of sewage sludge and high concentration phenolic wastewater for production of solid biofuel with increased calorific value. J. Clean. Prod.255, 120317.
[114]	Wang, T.F., Zhai, Y.B., Zhu, Y., Li, C.T., Zeng, G.M., 2018b. A review of the hydrothermal carbonization of biomass waste for hydrochar formation: process conditions, fundamentals, and physicochemical properties. Renew. Sustain. Energy Rev.90, 223-247.
[115]	Wang, T.L., Xiao, Z.S., Li, T.G., Guo, G., Chen, S.Y., Huang, X.Q., 2023. Improving the quality of soluble dietary fiber from Poria cocos peel residue following steam explosion. Food Chem. X19, 100829.
[116]	Willson N.L., Van T.T.H., Bhattarai S.P., Courtice J.M., McIntyre J.R., Prasai T.P., Moore R.J., Walsh K., Stanley D., 2019. Feed supplementation with biochar may reduce poultry pathogens, including Campylobacter hepaticus, the causative agent of Spotty Liver Disease. PLoS One 14, e0214471.
[117]	Xiao M.Z., Chen W.J., Hong S., Pang B., Cao X.F., Wang Y.Y., Yuan T.Q., Sun R.C., 2019. Structural characterization of lignin in heartwood, sapwood, and bark of Eucalyptus. Int. J. Biol. Macromol.138, 519-527.
[118]	Xie, L., Meng, Y., Wang, Q.R., Zhang, G.Z., Xie, H.M., Zhou, G.L., 2022. Zanthoxylum bungeanum branches activated carbons with rich micropore structure prepared by low temperature H₃PO₄ hydrothermal pretreatment method for toluene adsorption. Diam. Relat. Mater.130, 109474.
[119]	Xiong, B.L., Ma, S., Chen, B.L., Feng, Y.C., Peng, Z.Q., Tang, X., Yang, S.L., Sun, Y., Lin, L., Zeng, X.H., Chen, Y., 2023. Formic acid-facilitated hydrothermal pretreatment of raw biomass for co-producing xylo-oligosaccharides, glucose, and lignin. Ind. Crops Prod.193, 116195.
[120]	Xu, C.Z., Tong, S.S., Sun, L.Q., Gu, X.L., 2023a. Cellulase immobilization to enhance enzymatic hydrolysis of lignocellulosic biomass: an all-inclusive review. Carbohydr. Polym.321, 121319.
[121]	Xu, L., Zhang, A.T., Liao, R.J., Pang, Y.X., Yang, D.J., Lou, H.M., Qiu, X.Q., 2023b. Copolymer with tunable cation content as an efficient promoter in enzymatic saccharification of lignocellulose. ACS Appl. Polym. Mater.5, 8997-9006.
[122]	Xu, Y.Y., Boeing, W.J., 2013. Mapping biofuel field: a bibliometric evaluation of research output. Renew. Sustain. Energy Rev.28, 82-91.
[123]	Yan, L.F., Li, W., Yang, J.L., Zhu, Q.S., 2004. Direct visualization of straw cell walls by AFM. Macromol. Biosci.4, 112-118.
[124]	Yan, L.S., Ma, R.S., Li, L.Z., Fu, J.L., 2016. Hot water pretreatment of lignocellulosic biomass: an effective and environmentally friendly approach to enhance biofuel production. Chem. Eng. Technol.39, 1759-1770.
[125]	Yang, B., Tao, L., Wyman, C.E., 2018. Strengths, challenges, and opportunities for hydrothermal pretreatment in lignocellulosic biorefineries. Biofuels Bioprod. Biorefin.12, 125-138.
[126]	Yang, J.T., Zhang, Z.M., Wang, J.Y., Zhao, X.L., Zhao, Y., Qian, J.Q., Wang, T.F., 2023. Pyrolysis and hydrothermal carbonization of biowaste: a comparative review on the conversion pathways and potential applications of char product. Sustain. Chem. Pharm.33, 101106.
[127]	Yao, F., Ye, G.Z., Peng, W.X., Zhao, G.Y., Wang, X.H., Wang, Y.Q., Zhu, W.F., Jiao, Y.J., Huang, H.M., Ye, D.Q., 2023. Preparation of activated biochar with adjustable pore structure by hydrothermal carbonization for efficient adsorption of VOCs and its practical application prospects. J. Environ. Chem. Eng.11, 109611.
[128]	Ying, W.J., Shi, Z.J., Yang, H.Y., Xu, G.F., Zheng, Z.F., Yang, J., 2018. Effect of alkaline lignin modification on cellulase-lignin interactions and enzymatic saccharification yield. Biotechnol. Biofuels 11, 214.
[129]	Yue, P.P., Hu, Y.J., Tian, R., Bian, J., Peng, F., 2022. Hydrothermal pretreatment for the production of oligosaccharides: a review. Bioresour. Technol.343, 126075.
[130]	Zhang, J.H., Wen, P.Y., Lin, Z.H., Ying, W.J., 2024. A review of enhancement of lignocellulose enzymatic hydrolysis via hydrogen peroxide pretreatments. J. For. Eng.9, 1-13.
[131]	Zhang, Q., Rong, G., Meng, Q.G., Yu, M., Xie, Q.Y., Fang, J., 2020. Outlining the keyword co-occurrence trends in Shuanghuanglian injection research: a bibliometric study using CiteSpace III. J. Tradit. Chin. Med. Sci.7, 189-198.
[132]	Zhang, Z.M., Yang, J.T., Qian, J.Q., Zhao, Y., Wang, T.F., Zhai, Y.B., 2021. Biowaste hydrothermal carbonization for hydrochar valorization: skeleton structure, conversion pathways and clean biofuel applications. Bioresour. Technol.324, 124686.
[133]	Zhao, Y., Shakeel, U., Saif Ur Rehman, M., Li, H.Q., Xu, X., Xu, J., 2020. Lignin-carbohydrate complexes (LCCs) and its role in biorefinery. J. Clean. Prod.253, 120076.
[134]	Zhao, Z.Z., Shao, Z.J., Qu, Q., Ji, M.Q., Cheng, D.M., Guo, X.H., 2023. Promoting the overall energy profit through using the liquid hydrolysate during microwave hydrothermal pretreatment of wheat straw as co-substrate for anaerobic digestion. Sci. Total Environ.857, 159463.
[135]	Zhou, R.J., Lin, X.L., Liu, D.M., Li, Z., Zeng, J.C., Lin, X.D., Liang, X.D., 2022. Research hotspots and trends analysis of TFEB: a bibliometric and scientometric analysis. Front. Mol. Neurosci.15, 854954.
[136]	Zhuang, X.Z., Liu, J.G., Wang, C.G., Zhang, Q., Ma, L.L., 2022. Microwave-assisted hydrothermal liquefaction for biomass valorization: insights into the fuel properties of biocrude and its liquefaction mechanism. Fuel 317, 123462.
[137]	Zou, S.L., Xiao, L.P., Li, X.Y., Yin, W.Z., Sun, R.C., 2023. Lignin-based composites with enhanced mechanical properties by acetone fractionation and epoxidation modification. iScience 26, 106187.