Organic Waste Conversion to Biofuels: A Sustainable Approach
الموضوعات : Biotechnological Journal of Environmental Microbiology
Abdul Razak Mohamed Sikkander
1
,
Hala S. Abuelmakarem
2
1 - Department of Chemistry, Velammal Engineering College, Chennai -600066 Tamilnadu INDIA
2 - Department of Biomedical Engineering, College of Engineering, King Faisal University, Al-Ahsa, 31982, Saudi Arabia
الکلمات المفتاحية: Organic waste, Biofuels, Biohydrogen, Biomethane, Biopropane, Microbial fermentation, Anaerobic digestion,
ملخص المقالة :
This study examines the potential of converting organic waste into valuable biofuels, including biohydrogen, biomethane, and biopropane, through microbial fermentation and anaerobic digestion. Organic residues such as food waste, agricultural byproducts, and sewage sludge serve as renewable feedstocks for these bioprocesses, enabling the transformation of otherwise discarded materials into energy-rich compounds. By harnessing the metabolic capabilities of microorganisms, these processes offer a sustainable approach to waste management while simultaneously generating renewable energy, contributing to both environmental and economic benefits.Biohydrogen, produced through dark or photo-fermentation, represents a clean and high-energy fuel with minimal greenhouse gas emissions. Similarly, biomethane generated via anaerobic digestion can be used as a direct substitute for natural gas, while biopropane offers potential as a renewable alternative for industrial and domestic energy applications. These biofuels not only reduce dependence on fossil fuels but also play a critical role in mitigating climate change by capturing carbon present in organic waste streams and preventing methane release from uncontrolled decomposition.
Recent research has focused on optimizing microbial consortia, refining reactor designs, and improving process parameters such as temperature, pH, and nutrient availability to enhance biofuel yield and process efficiency. Advances in scaling up these technologies have demonstrated their feasibility for industrial applications, supporting the development of integrated biorefineries that convert waste into multiple valuable products.Overall, the microbial conversion of organic waste into biofuels exemplifies a circular economy approach, where waste materials are transformed into sustainable energy resources. By promoting renewable energy generation, reducing greenhouse gas emissions, and improving waste management, these bioprocesses highlight the potential of biotechnology to address pressing environmental challenges while fostering sustainable industrial practices.
المصادر:
1. Raman S, Mohr A. Biofuels and the role of space in sustainable innovation journeys. Journal of Cleaner Production. 2013;65:224-233. doi:10.1016/j.jclepro.2013.07.057
2. Salam M, Grossule V, Elouali S, et al. Sustainable biowaste management: Uncovering the environmental footprint of traditional and emerging waste managing technologies. Environmental Chemistry and Ecotoxicology. July 2025. doi:10.1016/j.enceco.2025.07.012
3. Zhang Y, Li L, Xu P, Liu B, Shuai Y, Li B. Hydrogen production through biomass gasification in supercritical water: A review from exergy aspect. International Journal of Hydrogen Energy. 2019;44(30):15727-15736. doi:10.1016/j.ijhydene.2019.01.151
4. Ishaq H, Dincer I. Comparative assessment of renewable energy-based hydrogen production methods. Renewable and Sustainable Energy Reviews. 2020;135:110192. doi:10.1016/j.rser.2020.110192
5. Zhang Q, Hu M, Wang J, et al. Synthesis of silicotungstic Acid/Ni-ZR-O composite nanoparticle by using bimetallic Ni-ZR MOF for fatty acid esterification. Catalysts. 2022;13(1):40. doi:10.3390/catal13010040
6. Zhang Q, Yang B, Tian Y, et al. Fabrication of silicotungstic acid immobilized on Ce-based MOF and embedded in Zr-based MOF matrix for green fatty acid esterification. Green Processing and Synthesis. 2022;11(1):184-194. doi:10.1515/gps-2022-0021
7. Castillo AB, Cortes DJD, Sorino CF, Soriño CKP, El-Naas MH, Ahmed T. Bioethanol Production from Waste and Nonsalable Date Palm (Phoenix dactylifera L.) Fruits: Potentials and Challenges. Sustainability. 2023;15(4):2937. doi:10.3390/su15042937
8. Iqbal Z, Siddiqua A, Anwar Z, Munir M. Valorization of Delonix regia Pods for Bioethanol Production. Fermentation. 2023;9(3):289. doi:10.3390/fermentation9030289
9. Tsolcha ON, Patrinou V, Economou CN, Dourou M, Aggelis G, Tekerlekopoulou AG. Utilization of Biomass Derived from Cyanobacteria-Based Agro-Industrial Wastewater Treatment and Raisin Residue Extract for Bioethanol Production. Water. 2021;13(4):486. doi:10.3390/w13040486
10. Anniwaer A, Chaihad N, Zhang M, et al. Hydrogen-rich gas production from steam co-gasification of banana peel with agricultural residues and woody biomass. Waste Management. 2021;125:204-214. doi:10.1016/j.wasman.2021.02.042
11. Poornima, S.; Manikandan, S.; Prakash, R.; Deena, S.R.; Subbaiya, R.; Karmegam, N.; Govarthanan, M. Biofuel and biochemical production through biomass transformation using advanced thermochemical and biochemical processes—A review. Fuel 2024, 372, 132204.
12. Begum, Y.A.; Kumari, S.; Jain, S.K.; Garg, M.C. A review on waste biomass-to-energy: Integrated thermochemical and biochemical conversion for resource recovery. Environ. Sci. Adv. 2024, 3, 1197–1216.
13. Panwar, N.L.; Divyangkumar, N. An overview of recent advancements in biomass torrefaction. Environ. Dev. Sustain. 2024, 1, 1–48.
14. Hidalgo, D.; Urueña, A.; Díez, D.; Martín-Marroquín, J.M. Hydrothermal Carbonization of Industrial Sludge: Recent Advances, Challenges, and Perspectives. In Recent Trends in Management and Utilization of Industrial Sludge; Springer Nature: Cham, Switzerland, 2024; pp. 95–123.
15. El Bari, H.; Fanezoune, C.K.; Dorneanu, B.; Arellano-Garcia, H.; Majozi, T.; Elhenawy, Y.; Ashour, F.J. Catalytic fast pyrolysis of lignocellulosic biomass: Recent advances and comprehensive overview. Anal. Appl. Pyrolysis 2024, 178, 106390.
16. Li, J.; Xu, K.; Yao, X.; Liu, J. Investigation of biomass slow pyrolysis mechanisms based on the generation trends in pyrolysis products. Process Saf. Environ. Prot. 2024, 183, 327–338.
17. Shahbeik, H.; Panahi, H.K.S.; Dehhaghi, M.; Guillemin, G.J.; Fallahi, A.; Hosseinzadeh-Bandbafha, H.; Aghbashlo, M. Biomass to biofuels using hydrothermal liquefaction: A comprehensive review. Renew. Sustain. Energy Rev. 2024, 189, 113976.
18. Sher, F.; Hameed, S.; Omerbegović, N.S.; Chupin, A.; Hai, I.U.; Wang, B.; Yildiz, M.J. Cutting-edge biomass gasification technologies for renewable energy generation and achieving net zero emissions. Energy Convers. Manag. 2025, 323, 119213.
19. Costa, J.C.; Dias, I.M.; Mourão, L.C.; de Souza, G.B.; Pereira, M.B.; Freitas, F.F.; Alonso, C.G. Supercritical water gasification of food waste for hydrogen production. Renew. Sustain. Energy Rev. 2025, 208, 115091.
20. Durán-Valle, C.J.; López-Coca, I.M. Biochemical and Thermochemical Conversion Technologies for Agriculture Waste Transformation. In Transforming Agriculture Residues for Sustainable Development: From Waste to Wealth; Springer Nature: Cham, Switzerland, 2024; pp. 47–84.
21. Song, X.; Jia, X.; An, P.; Han, Z.; Xu, G. Development of science and technology in thermochemical reaction engineering. Chem. Ind. Eng. Prog. 2024, 43, 3513–3533.
22. Hidalgo, D.; Corona, F. Livestock Manure Valorization to Biochemical’s and Energy. In Manure Technology and Sustainable Development; Springer Nature: Singapore, 2023; pp. 211–239.
23. Li, X.; Wang, Z.; He, Y.; Wang, Y.; Wang, S.; Zheng, Z.; Ying, H. A comprehensive review of the strategies to improve anaerobic digestion: Their mechanism and digestion performance. Methane 2024, 3, 227–256.
24. Hmaissia, A.; Hernández, E.M.; Vaneeckhaute, C. Comparing sewage sludge vs. digested sludge for starting-up thermophilic two-stage anaerobic digesters: Operational and economic insights. Waste Manag. 2025, 194, 24–35.
25. Stoll, I.K.; Boukis, N.; Sauer, J. Syngas fermentation to alcohols: Reactor technology and application perspective. Chem. Ing. Tech. 2020, 92, 125–136.
26. Elisiário, M.P.; De Wever, H.; Van Hecke, W.; Noorman, H.; Straathof, A.J. Membrane bioreactors for syngas permeation and fermentation. Crit. Rev. Biotechnol. 2022, 42, 856–872.
27. Chen, H.; Xia, A.; Yan, H.; Huang, Y.; Zhu, X.; Zhu, X.; Liao, Q. Mass transfer in heterogeneous biofilms: Key issues in biofilm reactors and AI-driven performance prediction. Environ. Sci. Ecotechnology 2024, 22, 100480.
28. Neto, A.S.; Wainaina, S.; Chandolias, K.; Piatek, P.; Taherzadeh, M.J. Exploring the Potential of Syngas Fermentation for Recovery of High-Value Resources: A Comprehensive Review. Curr. Pollut. Rep. 2025, 11, 7.
29. Shahzad, H.M.A.; Asim, Z.; Khan, S.J.; Almomani, F.; Mahmoud, K.A.; Mustafa, M.R.U.; Rasool, K. Thermochemical and biochemical conversion of agricultural waste for bioenergy production: An updated review. Discov. Environ. 2024, 2, 134.
30. Torri, C.; Rombolà, A.G.; Kiwan, A.; Fabbri, D. Biomass Valorization: Sustainable Methods for the Production of Chemicals; University of Pavia: Pavia, Italy, 2021; pp. 181–223.
31. Tayibi, S.; Monlau, F.; Marias, F.; Cazaudehore, G.; Fayoud, N.E.; Oukarroum, A.; Zeroual, Y.; Barakat, A.J. Coupling anaerobic digestion and pyrolysis processes for maximizing energy recovery and soil preservation according to the circular economy concept. Environ. Manag. 2021, 279, 111632.
32. Ebrahimi, A.; Houshfar, E. A comprehensive exergoeconomic analysis of pyrolysis, anaerobic digestion, and integrated Py-AD plants for sustainable energy and waste management. Fuel 2025, 384, 133928.
33. Okopi, S.I.; Zeng, J.; Fan, X.; Lu, J.; Cui, J.; Hu, Y.; Xu, F. Environmental sustainability assessment of a new food waste anaerobic digestion and pyrolysis hybridization system. Waste Manag. 2024, 179, 130–143.
34. W.; Robinson, J. Comparison of bio-oils derived from crop digestate treated through conventional and microwave pyrolysis as an alternative route for further waste valorization. Biomass Convers. Biorefinery 2024, 14, 15739–15754.
35. An, Q.; Liu, Y.; Cao, X.; Yang, P.; Cheng, L.; Ghazani, M.S.; Bi, X.J. Microwave catalytic pyrolysis of solid digestate for high quality bio-oil and biochar. Anal. Appl. Pyrolysis 2024, 182, 106683.
36. Sikarwar, V.S.; Pohořelý, M.; Meers, E.; Skoblia, S.; Moško, J.; Jeremiáš, M. Potential of coupling anaerobic digestion with thermochemical technologies for waste valorization. Fuel 2021, 294, 120533.
37. Couto, E.; Calijuri, M.L.; Assemany, P. Biomass production in high rate ponds and hydrothermal liquefaction: Wastewater treatment and bioenergy integration. Sci. Total Environ. 2020, 724, 138104.
38. Yang, L.; Si, B.; Tan, X.; Chu, H.; Zhou, X.; Zhang, Y.; Zhang, Y.; Zhao, F. Integrated anaerobic digestion and algae cultivation for energy recovery and nutrient supply from post-hydrothermal liquefaction wastewater. Bioresour. Technol. 2018, 266, 349–356.
39. Tatla, H.K.; Ismail, S.; Khan, M.A.; Dhar, B.R.; Gupta, R. Coupling hydrothermal liquefaction and anaerobic digestion for waste biomass valorization: A review in context of circular economy. Chemosphere 2024, 361, 142419.
40. Frugoli, G.Z.; Dias, M.E.S.; Tommaso, G. Anaerobic digestion of hydrothermal liquefaction wastewater and biochar from spent coffee grounds. Waste Biomass Valorization 2022, 13, 3877–3886.
41. Jha, S.; Okolie, J.A.; Nanda, S.; Dalai, A.K. A review of biomass resources and thermochemical conversion technologies. Chem. Eng. Technol. 2022, 45, 791–799.
42. World Bioenergy Association. Global Bioenergy Statistics 2020; World Bioenergy Association: Stockholm, Sweden, 2020; Volume 3, p. 49.
43. IEA. Renewables 2021: Biofuels. Available online: https://www.iea.org/reports/renewables-2021/biofuels?mode=transport®ion=World&publication=2021&flow=Consumption&product=Ethanol (accessed on 22 August 2022).
44. Lee, S.Y.; Sankaran, R.; Chew, K.W.; Tan, C.H.; Krishnamoorthy, R.; Chu, D.T.; Show, P.L. Waste to bioenergy: A review on the recent conversion technologies. BMC Energy 2019, 1, 4.
45. Xing, J.; Luo, K.; Wang, H.; Gao, Z.; Fan, J. A comprehensive study on estimating higher heating value of biomass from proximate and ultimate analysis with machine learning approaches. Energy 2019, 188, 116077.
46. Namkung, H.; Lee, Y.J.; Park, J.H.; Song, G.S.; Choi, J.W.; Kim, J.G.; Park, S.J.; Park, J.C.; Kim, H.T.; Choi, Y.C. Influence of herbaceous biomass ash pre-treated by alkali metal leaching on the agglomeration/sintering and corrosion behaviors. Energy 2019, 187, 115950.
47. Güleç, F.; Pekaslan, D.; Williams, O.; Lester, E. Predictability of higher heating value of biomass feedstocks via proximate and ultimate analyses—A comprehensive study of artificial neural network applications. Fuel 2022, 320, 123944.
48. Singh, A.; Nanda, S.; Guayaquil-Sosa, J.F.; Berruti, F. Pyrolysis of Miscanthus and characterization of value-added bio-oil and biochar products. Can. J. Chem. Eng. 2021, 99, S55–S68.
49. Khan, I.U.; Chen, H.; Yan, Z.; Chen, J. Extraction and quality evaluation of biodiesel from six familiar non-edible plants seeds. Processes 2021, 9, 840.
50. Kumar, A.; Samadder, S.R. An empirical model for prediction of household solid waste generation rate—A case study of Dhanbad, India. Waste Manag. 2017, 68, 3–15.
51. Nanda, S.; Berruti, F. Municipal solid waste management and landfilling technologies: A review. Environ. Chem. Lett. 2021, 19, 1433–1456.
52. Rajendran, N.; Gurunathan, B.; Han, J.; Krishna, S.; Ananth, A.; Venugopal, K.; Priyanka, R.S. Recent advances in valorization of organic municipal waste into energy using biorefinery approach, environment and economic analysis. Bioresour. Technol. 2021, 337, 125498.
53. Gunarathne, V.; Ashiq, A.; Ramanayaka, S.; Wijekoon, P.; Vithanage, M. Biochar from municipal solid waste for resource recovery and pollution remediation. Environ. Chem. Lett. 2019, 17, 1225–1235.
54. Fazeli, A.; Bakhtvar, F.; Jahanshaloo, L.; Sidik, N.A.C.; Bayat, A.E. Malaysia’s stand on municipal solid waste conversion to energy: A review. Renew. Sustain. Energy Rev. 2016, 58, 1007–1016.
55. Ouda, O.K.; Cekirge, H.M.; Raza, S.A. An assessment of the potential contribution from waste-to-energy facilities to electricity demand in Saudi Arabia. Energy Convers. Manag. 2013, 75, 402–406.
56. Clavier, K.A.; Paris, J.M.; Ferraro, C.C.; Townsend, T.G. Opportunities and challenges associated with using municipal waste incineration ash as a raw ingredient in cement production—A review. Resour. Conserv. Recycl. 2020, 160, 104888.
57. Mishra, S.; Tiwary, D.; Ohri, A.; Agnihotri, A.K. Impact of municipal solid waste landfill leachate on groundwater quality in Varanasi, India. Groundw. Sustain. Dev. 2019, 9, 100230.
58. Nanda, S.; Isen, J.; Dalai, A.K.; Kozinski, J.A. Gasification of fruit wastes and agro-food residues in supercritical water. Energy Convers. Manag. 2016, 110, 296–306.
59. Kiran, E.U.; Trzcinski, A.P.; Ng, W.J.; Liu, Y. Bioconversion of food waste to energy: A review. Fuel 2014, 134, 389–399.
60. Ren, Y.; Wang, C.; He, Z.; Qin, Y.; Li, Y.Y. Enhanced biomethanation of lipids by high-solid co-digestion with food waste: Biogas production and lipids degradation demonstrated by long-term continuous operation. Bioresour. Technol. 2022, 348, 126750.
61. Kiran, E.U.; Liu, Y. Bioethanol production from mixed food waste by an effective enzymatic pretreatment. Fuel 2015, 159, 463–469.
62. Qin, Z.; Duns, G.J.; Pan, T.; Xin, F. Consolidated processing of biobutanol production from food wastes by solventogenic Clostridium sp. strain HN4. Bioresour. Technol. 2018, 264, 148–153.
63. Yasin, N.H.M.; Mumtaz, T.; Hassan, M.A.; Rahman, N.A. Food waste and food processing waste for biohydrogen production: A review. J. Environ. Manag. 2013, 130, 375–385.
64. Patra, B.R.; Nanda, S.; Dalai, A.K.; Meda, V. Slow pyrolysis of agro-food wastes and physicochemical characterization of biofuel products. Chemosphere 2021, 285, 131431.
65. Patra, B.R.; Nanda, S.; Dalai, A.K.; Meda, V. Taguchi-based process optimization for activation of agro-food waste biochar and performance test for dye adsorption. Chemosphere 2021, 285, 131531.
66. Nguyen, B.T.; Trinh, N.N.; Bach, Q.V. Methane emissions and associated microbial activities from paddy salt-affected soil as influenced by biochar and cow manure addition. Appl. Soil Ecol. 2020, 152, 103531.
67. Khoshnevisan, B.; Duan, N.; Tsapekos, P.; Awasthi, M.K.; Liu, Z.; Mohammadi, A.; Angelidaki, I.; Tsang, D.C.; Zhang, Z.; Pan, J.; et al. A critical review on livestock manure biorefinery technologies: Sustainability, challenges, and future perspectives. Renew. Sustain. Energy Rev. 2021, 135, 110033.
68. Yao, Y.; Huang, G.; An, C.; Chen, X.; Zhang, P.; Xin, X.; Shen, J.; Agnew, J. Anaerobic digestion of livestock manure in cold regions: Technological advancements and global impacts. Renew. Sustain. Energy Rev. 2020, 119, 109494.
69. Dareioti, M.A.; Vavouraki, A.I.; Tsigkou, K.; Zafiri, C.; Kornaros, M. Dark fermentation of sweet sorghum stalks, cheese whey and cow manure mixture: Effect of pH, pretreatment and organic load. Processes 2021, 9, 1017.
70. Yan, Q.; Liu, X.; Wang, Y.; Li, H.; Li, Z.; Zhou, L.; Qu, Y.; Li, Z.; Bao, X. Cow manure as a lignocellulosic substrate for fungal cellulase expression and bioethanol production. AMB Exp. 2018, 8, 190.
71. Su, G.; Ong, H.C.; Zulkifli, N.W.M.; Ibrahim, S.; Chen, W.H.C.; Chong, C.T.; Ok, Y.S. Valorization of animal manure via pyrolysis for bioenergy: A review. J. Clean. Prod. 2022, 343, 130965.
72. Liu, Q.; Xua, R.; Yan, C.; Han, L.; Lei, H.; Ruan, R.; Zhang, X. Fast hydrothermal co-liquefaction of corn stover and cow manure for biocrude and hydrochar production. Bioresour. Technol. 2021, 340, 125630.
73. Nanda, S.; Dalai, A.K.; Gökalp, I.; Kozinski, J.A. Valorization of horse manure through catalytic supercritical water gasification. Waste Manag. 2016, 52, 147–158.
74. Itoh, T.; Iwabuchi, K.; Maemoku, N.; Sasaki, I.; Taniguro, K. A new torrefaction system employing spontaneous self-heating of livestock manure under elevated pressure. Waste Manag. 2019, 85, 66–72.
75. Cheong, D.Y.; Harvey, J.T.; Kim, J.; Lee, C. Improving biomethanation of chicken manure by co-digestion with ethanol plant effluent. Int. J. Env. Res. Public Health 2019, 16, 5023.
76. Yong, T.L.K.; Matsumura, Y. Catalytic gasification of poultry manure and eucalyptus wood mixture in supercritical water. Ind. Eng. Chem. Res. 2012, 51, 5685–5690.
77. Sarker, T.R.; Nanda, S.; Dalai, A.K.; Meda, V. A review of torrefaction technology for upgrading lignocellulosic biomass to solid biofuels. BioEnergy Res. 2021, 14, 645–669. [Google Scholar] [CrossRef]
78. Basu, P.; Sadhukhan, A.K.; Gupta, P.; Rao, S.; Dhungana, A.; Acharya, B. An experimental and theoretical investigation on torrefaction of a large wet wood particle. Bioresour. Technol. 2014, 159, 215–222.
79. Chen, W.H.; Peng, J.; Bi, X.T. A state-of-the-art review of biomass torrefaction, densification and applications. Renew. Sustain. Energy Rev. 2015, 44, 847–866.
80. Acharya, B.; Dutta, A.; Minaret, J. Review on comparative study of dry and wet torrefaction. Sustain. Energy Technol. Assess. 2015, 12, 26–37.
81. Osman WNAW, Rosli MH, Mazli WNA, Samsuri S. Comparative review of biodiesel production and purification. Carbon Capture Science & Technology. 2024;13:100264. doi:10.1016/j.ccst.2024.100264
82. Zhang C, Singh RP, Yadav P, et al. Recent advances in biotechnology and bioengineering for efficient microalgal biofuel production. Fuel Processing Technology. 2025;270:108199. doi:10.1016/j.fuproc.2025.108199
83. Ahmed N, Shakoor N. Advancing Agriculture through IoT, Big Data, and AI: A Review of Smart Technologies Enabling Sustainability. Smart Agricultural Technology. February 2025:100848. doi:10.1016/j.atech.2025.100848
84. Shah V, Patel N, Prajapati P, Jouhara H. Unlocking biogas potential: A comprehensive study on pretreatment techniques of organic substrate for enhanced anaerobic digestion. Energy. 2025;335:138244. doi:10.1016/j.energy.2025.138244
85. Chowdhury P, Mahi NA, Yeassin R, Chowdhury NUR, Farrok O. Biomass to biofuel: Impacts and mitigation of environmental, health, and socioeconomic challenges. Energy Conversion and Management X. 2025;25:100889. doi:10.1016/j.ecmx.2025.100889
86. Sofán-Germán SJ, Doria-Oviedo ME, Rhenals-Julio JD, Mendoza-Fandiño JM. Life Cycle Assessment of Biomass Waste and Coal Co-Firing: Advancing Circular Economy in Energy Production. Recycling. 2025; 10(4):151. https://doi.org/10.3390/recycling10040151
87. Kaur S, Kumar R, Singh K, Singh S. Systematic review of hydrogen, biomass, biogas, and solar photovoltaics in hybrid renewable energy systems: Advancements, challenges, and future directions. International Journal of Hydrogen Energy. 2025;137:160-189. doi:10.1016/j.ijhydene.2025.04.525
88. Alcocer-García H, Sánchez-Ramírez E, García-García E, Ramírez-Márquez C, Ponce-Ortega JM. Unlocking the Potential of Biomass Resources: A Review on Sustainable Process Design and Intensification. Resources. 2025; 14(9):143. https://doi.org/10.3390/resources14090143
89. El-Fawal EM, El Naggar AMA, El-Zahhar AA, Alghandi MM, Morshedy AS, El Sayed HA, Mohammed AEME. Biofuel production from waste residuals: comprehensive insights into biomass conversion technologies and engineered biochar applications. RSC Adv. 2025 Apr 22;15(15):11942-11974. doi: 10.1039/d5ra00857c. Erratum in: RSC Adv. 2025 May 16;15(21):16468. doi: 10.1039/d5ra90054a.
90. Saravanan A, Ragini YP, Karishma S, Hemavathy RV, Jyotsna M. A review on advancing sustainable energy: The role of biomass and bioenergy in a circular economy. Sustainable Futures. 2025;10:100835. doi:10.1016/j.sftr.2025.100835
91. Llanos-Lizcano R, Senila L, Modoi OC. Evaluation of Biochemical Methane Potential and Kinetics of Organic Waste Streams for Enhanced Biogas Production. Agronomy. 2024; 14(11):2546. https://doi.org/10.3390/agronomy14112546
92. Sahith N V, J AK, Sruthi S V. Microbial biofuels: a comprehensive review of advances toward sustainable energy and environmental mitigation. International Journal of Ambient Energy. 2025;46(1). doi:10.1080/01430750.2025.2571520
93. Nabaterega R, Vesuwe RN, Iorhemen OT, Thring RW. Biodiesel production unpacked: Data-driven analysis of key operational factors. Biomass and Bioenergy. 2025;205:108457. doi:10.1016/j.biombioe.2025.108457
94. Naseef HH, Tulaimat RH. Transesterification and esterification for biodiesel production: A comprehensive review of catalysts and palm oil feedstocks. Energy Conversion and Management X. February 2025:100931. doi:10.1016/j.ecmx.2025.100931
95. Babu KKBS, Nataraj M, Tayappa M, Vyas Y, Mishra RK, Acharya B. Production of biochar from waste biomass using slow pyrolysis: Studies of the effect of pyrolysis temperature and holding time on biochar yield and properties. Materials Science for Energy Technologies. 2024;7:318-334. doi:10.1016/j.mset.2024.05.002
96. Gao Y, Wang M, Raheem A, et al. Syngas Production from Biomass Gasification: Influences of Feedstock Properties, Reactor Type, and Reaction Parameters. ACS Omega. 2023;8(35):31620-31631. doi:10.1021/acsomega.3c03050
97. Shrestha S, Pandey R, Aryal N, Lohani SP. Recent advances in co-digestion conjugates for anaerobic digestion of food waste. Journal of Environmental Management. 2023;345:118785. doi:10.1016/j.jenvman.2023.118785
98. Kazmi A, Sultana T, Ali A, Nijabat A, Li G, Hou H. Innovations in bioethanol production: A comprehensive review of feedstock generations and technology advances. Energy Strategy Reviews. 2025;57:101634. doi:10.1016/j.esr.2024.101634
99. Farouk SM, Tayeb AM, Abdel-Hamid SMS, Osman RM. Recent advances in transesterification for sustainable biodiesel production, challenges, and prospects: a comprehensive review. Environmental Science and Pollution Research. 2024;31(9):12722-12747. doi:10.1007/s11356-024-32027-4
100. Liu Y, Sun Y, Wu X, et al. In-situ hydrodeoxygenation of a lignin-derived monomer using Ar dielectric barrier discharge plasma: From conversion performance to mechanism analysis. Journal of the Energy Institute. 2025;124:102344. doi:10.1016/j.joei.2025.102344
101. Prestipino M, Corigliano O, Galvagno A, Piccolo A, Fragiacomo P. Exploring the potential of wet biomass gasification with SOFC and ICE cogeneration technologies: process design, simulation and comparative thermodynamic analysis. Applied Energy. 2025;392:125998. doi:10.1016/j.apenergy.2025.125998
102. Song YJ, Oh KS, Lee B, Pak DW, Cha JH, Park JG. Characteristics of Biogas Production from Organic Wastes Mixed at Optimal Ratios in an Anaerobic Co-Digestion Reactor. Energies. 2021;14(20):6812. doi:10.3390/en14206812
103. Tsegaye KN, Alemnew M, Berhane N. Saccharomyces cerevisiae for lignocellulosic ethanol production: a look at key attributes and genome shuffling. Frontiers in Bioengineering and Biotechnology. 2024;12. doi:10.3389/fbioe.2024.1466644
104. Monika N, Banga S, Pathak VV. Biodiesel production from waste cooking oil: A comprehensive review on the application of heterogenous catalysts. Energy Nexus. 2023;10:100209. doi:10.1016/j.nexus.2023.100209
105. Parvari E, Mahajan D, Hewitt EL. A Review of Biomass Pyrolysis for Production of Fuels: Chemistry, Processing, and Techno-Economic Analysis. Biomass. 2025; 5(3):54. https://doi.org/10.3390/biomass5030054
106. Natarajan A, Venugopal D, Thangavelu L. Investigation of biomass gasification simulation using air, steam and oxygen as gasifying agent. Thermal Science. 2022;26(6 part B):5109-5119. doi:10.2298/tsci220207092n
107. Sarwar H, Vuppaladadiyam A, Venkatachalapati A, et al. Pre-treatment of organic biomass in the context of stand-alone and integrated anaerobic digestion–pyrolysis for enhanced product recovery: A critical review of challenges and opportunities. Biomass and Bioenergy. 2025;204:108386. doi:10.1016/j.biombioe.2025.108386
108. Kataya G, Cornu D, Bechelany M, Hijazi A, Issa M. Biomass Waste Conversion Technologies and Its Application for Sustainable Environmental Development—A Review. Agronomy. 2023; 13(11):2833. https://doi.org/10.3390/agronomy13112833
1. Raman S, Mohr A. Biofuels and the role of space in sustainable innovation journeys. Journal of Cleaner Production. 2013;65:224-233. doi:10.1016/j.jclepro.2013.07.057
2. Salam M, Grossule V, Elouali S, et al. Sustainable biowaste management: Uncovering the environmental footprint of traditional and emerging waste managing technologies. Environmental Chemistry and Ecotoxicology. July 2025. doi:10.1016/j.enceco.2025.07.012
3. Zhang Y, Li L, Xu P, Liu B, Shuai Y, Li B. Hydrogen production through biomass gasification in supercritical water: A review from exergy aspect. International Journal of Hydrogen Energy. 2019;44(30):15727-15736. doi:10.1016/j.ijhydene.2019.01.151
4. Ishaq H, Dincer I. Comparative assessment of renewable energy-based hydrogen production methods. Renewable and Sustainable Energy Reviews. 2020;135:110192. doi:10.1016/j.rser.2020.110192
5. Zhang Q, Hu M, Wang J, et al. Synthesis of silicotungstic Acid/Ni-ZR-O composite nanoparticle by using bimetallic Ni-ZR MOF for fatty acid esterification. Catalysts. 2022;13(1):40. doi:10.3390/catal13010040
6. Zhang Q, Yang B, Tian Y, et al. Fabrication of silicotungstic acid immobilized on Ce-based MOF and embedded in Zr-based MOF matrix for green fatty acid esterification. Green Processing and Synthesis. 2022;11(1):184-194. doi:10.1515/gps-2022-0021
7. Castillo AB, Cortes DJD, Sorino CF, Soriño CKP, El-Naas MH, Ahmed T. Bioethanol Production from Waste and Nonsalable Date Palm (Phoenix dactylifera L.) Fruits: Potentials and Challenges. Sustainability. 2023;15(4):2937. doi:10.3390/su15042937
8. Iqbal Z, Siddiqua A, Anwar Z, Munir M. Valorization of Delonix regia Pods for Bioethanol Production. Fermentation. 2023;9(3):289. doi:10.3390/fermentation9030289
9. Tsolcha ON, Patrinou V, Economou CN, Dourou M, Aggelis G, Tekerlekopoulou AG. Utilization of Biomass Derived from Cyanobacteria-Based Agro-Industrial Wastewater Treatment and Raisin Residue Extract for Bioethanol Production. Water. 2021;13(4):486. doi:10.3390/w13040486
10. Anniwaer A, Chaihad N, Zhang M, et al. Hydrogen-rich gas production from steam co-gasification of banana peel with agricultural residues and woody biomass. Waste Management. 2021;125:204-214. doi:10.1016/j.wasman.2021.02.042
11. Poornima, S.; Manikandan, S.; Prakash, R.; Deena, S.R.; Subbaiya, R.; Karmegam, N.; Govarthanan, M. Biofuel and biochemical production through biomass transformation using advanced thermochemical and biochemical processes—A review. Fuel 2024, 372, 132204.
12. Begum, Y.A.; Kumari, S.; Jain, S.K.; Garg, M.C. A review on waste biomass-to-energy: Integrated thermochemical and biochemical conversion for resource recovery. Environ. Sci. Adv. 2024, 3, 1197–1216.
13. Panwar, N.L.; Divyangkumar, N. An overview of recent advancements in biomass torrefaction. Environ. Dev. Sustain. 2024, 1, 1–48.
14. Hidalgo, D.; Urueña, A.; Díez, D.; Martín-Marroquín, J.M. Hydrothermal Carbonization of Industrial Sludge: Recent Advances, Challenges, and Perspectives. In Recent Trends in Management and Utilization of Industrial Sludge; Springer Nature: Cham, Switzerland, 2024; pp. 95–123.
15. El Bari, H.; Fanezoune, C.K.; Dorneanu, B.; Arellano-Garcia, H.; Majozi, T.; Elhenawy, Y.; Ashour, F.J. Catalytic fast pyrolysis of lignocellulosic biomass: Recent advances and comprehensive overview. Anal. Appl. Pyrolysis 2024, 178, 106390.
16. Li, J.; Xu, K.; Yao, X.; Liu, J. Investigation of biomass slow pyrolysis mechanisms based on the generation trends in pyrolysis products. Process Saf. Environ. Prot. 2024, 183, 327–338.
17. Shahbeik, H.; Panahi, H.K.S.; Dehhaghi, M.; Guillemin, G.J.; Fallahi, A.; Hosseinzadeh-Bandbafha, H.; Aghbashlo, M. Biomass to biofuels using hydrothermal liquefaction: A comprehensive review. Renew. Sustain. Energy Rev. 2024, 189, 113976.
18. Sher, F.; Hameed, S.; Omerbegović, N.S.; Chupin, A.; Hai, I.U.; Wang, B.; Yildiz, M.J. Cutting-edge biomass gasification technologies for renewable energy generation and achieving net zero emissions. Energy Convers. Manag. 2025, 323, 119213.
19. Costa, J.C.; Dias, I.M.; Mourão, L.C.; de Souza, G.B.; Pereira, M.B.; Freitas, F.F.; Alonso, C.G. Supercritical water gasification of food waste for hydrogen production. Renew. Sustain. Energy Rev. 2025, 208, 115091.
20. Durán-Valle, C.J.; López-Coca, I.M. Biochemical and Thermochemical Conversion Technologies for Agriculture Waste Transformation. In Transforming Agriculture Residues for Sustainable Development: From Waste to Wealth; Springer Nature: Cham, Switzerland, 2024; pp. 47–84.
21. Song, X.; Jia, X.; An, P.; Han, Z.; Xu, G. Development of science and technology in thermochemical reaction engineering. Chem. Ind. Eng. Prog. 2024, 43, 3513–3533.
22. Hidalgo, D.; Corona, F. Livestock Manure Valorization to Biochemical’s and Energy. In Manure Technology and Sustainable Development; Springer Nature: Singapore, 2023; pp. 211–239.
23. Li, X.; Wang, Z.; He, Y.; Wang, Y.; Wang, S.; Zheng, Z.; Ying, H. A comprehensive review of the strategies to improve anaerobic digestion: Their mechanism and digestion performance. Methane 2024, 3, 227–256.
24. Hmaissia, A.; Hernández, E.M.; Vaneeckhaute, C. Comparing sewage sludge vs. digested sludge for starting-up thermophilic two-stage anaerobic digesters: Operational and economic insights. Waste Manag. 2025, 194, 24–35.
25. Stoll, I.K.; Boukis, N.; Sauer, J. Syngas fermentation to alcohols: Reactor technology and application perspective. Chem. Ing. Tech. 2020, 92, 125–136.
26. Elisiário, M.P.; De Wever, H.; Van Hecke, W.; Noorman, H.; Straathof, A.J. Membrane bioreactors for syngas permeation and fermentation. Crit. Rev. Biotechnol. 2022, 42, 856–872.
27. Chen, H.; Xia, A.; Yan, H.; Huang, Y.; Zhu, X.; Zhu, X.; Liao, Q. Mass transfer in heterogeneous biofilms: Key issues in biofilm reactors and AI-driven performance prediction. Environ. Sci. Ecotechnology 2024, 22, 100480.
28. Neto, A.S.; Wainaina, S.; Chandolias, K.; Piatek, P.; Taherzadeh, M.J. Exploring the Potential of Syngas Fermentation for Recovery of High-Value Resources: A Comprehensive Review. Curr. Pollut. Rep. 2025, 11, 7.
29. Shahzad, H.M.A.; Asim, Z.; Khan, S.J.; Almomani, F.; Mahmoud, K.A.; Mustafa, M.R.U.; Rasool, K. Thermochemical and biochemical conversion of agricultural waste for bioenergy production: An updated review. Discov. Environ. 2024, 2, 134.
30. Torri, C.; Rombolà, A.G.; Kiwan, A.; Fabbri, D. Biomass Valorization: Sustainable Methods for the Production of Chemicals; University of Pavia: Pavia, Italy, 2021; pp. 181–223.
31. Tayibi, S.; Monlau, F.; Marias, F.; Cazaudehore, G.; Fayoud, N.E.; Oukarroum, A.; Zeroual, Y.; Barakat, A.J. Coupling anaerobic digestion and pyrolysis processes for maximizing energy recovery and soil preservation according to the circular economy concept. Environ. Manag. 2021, 279, 111632.
32. Ebrahimi, A.; Houshfar, E. A comprehensive exergoeconomic analysis of pyrolysis, anaerobic digestion, and integrated Py-AD plants for sustainable energy and waste management. Fuel 2025, 384, 133928.
33. Okopi, S.I.; Zeng, J.; Fan, X.; Lu, J.; Cui, J.; Hu, Y.; Xu, F. Environmental sustainability assessment of a new food waste anaerobic digestion and pyrolysis hybridization system. Waste Manag. 2024, 179, 130–143.
34. W.; Robinson, J. Comparison of bio-oils derived from crop digestate treated through conventional and microwave pyrolysis as an alternative route for further waste valorization. Biomass Convers. Biorefinery 2024, 14, 15739–15754.
35. An, Q.; Liu, Y.; Cao, X.; Yang, P.; Cheng, L.; Ghazani, M.S.; Bi, X.J. Microwave catalytic pyrolysis of solid digestate for high quality bio-oil and biochar. Anal. Appl. Pyrolysis 2024, 182, 106683.
36. Sikarwar, V.S.; Pohořelý, M.; Meers, E.; Skoblia, S.; Moško, J.; Jeremiáš, M. Potential of coupling anaerobic digestion with thermochemical technologies for waste valorization. Fuel 2021, 294, 120533.
37. Couto, E.; Calijuri, M.L.; Assemany, P. Biomass production in high rate ponds and hydrothermal liquefaction: Wastewater treatment and bioenergy integration. Sci. Total Environ. 2020, 724, 138104.
38. Yang, L.; Si, B.; Tan, X.; Chu, H.; Zhou, X.; Zhang, Y.; Zhang, Y.; Zhao, F. Integrated anaerobic digestion and algae cultivation for energy recovery and nutrient supply from post-hydrothermal liquefaction wastewater. Bioresour. Technol. 2018, 266, 349–356.
39. Tatla, H.K.; Ismail, S.; Khan, M.A.; Dhar, B.R.; Gupta, R. Coupling hydrothermal liquefaction and anaerobic digestion for waste biomass valorization: A review in context of circular economy. Chemosphere 2024, 361, 142419.
40. Frugoli, G.Z.; Dias, M.E.S.; Tommaso, G. Anaerobic digestion of hydrothermal liquefaction wastewater and biochar from spent coffee grounds. Waste Biomass Valorization 2022, 13, 3877–3886.
41. Jha, S.; Okolie, J.A.; Nanda, S.; Dalai, A.K. A review of biomass resources and thermochemical conversion technologies. Chem. Eng. Technol. 2022, 45, 791–799.
42. World Bioenergy Association. Global Bioenergy Statistics 2020; World Bioenergy Association: Stockholm, Sweden, 2020; Volume 3, p. 49.
43. IEA. Renewables 2021: Biofuels. Available online: https://www.iea.org/reports/renewables-2021/biofuels?mode=transport®ion=World&publication=2021&flow=Consumption&product=Ethanol (accessed on 22 August 2022).
44. Lee, S.Y.; Sankaran, R.; Chew, K.W.; Tan, C.H.; Krishnamoorthy, R.; Chu, D.T.; Show, P.L. Waste to bioenergy: A review on the recent conversion technologies. BMC Energy 2019, 1, 4.
45. Xing, J.; Luo, K.; Wang, H.; Gao, Z.; Fan, J. A comprehensive study on estimating higher heating value of biomass from proximate and ultimate analysis with machine learning approaches. Energy 2019, 188, 116077.
46. Namkung, H.; Lee, Y.J.; Park, J.H.; Song, G.S.; Choi, J.W.; Kim, J.G.; Park, S.J.; Park, J.C.; Kim, H.T.; Choi, Y.C. Influence of herbaceous biomass ash pre-treated by alkali metal leaching on the agglomeration/sintering and corrosion behaviors. Energy 2019, 187, 115950.
47. Güleç, F.; Pekaslan, D.; Williams, O.; Lester, E. Predictability of higher heating value of biomass feedstocks via proximate and ultimate analyses—A comprehensive study of artificial neural network applications. Fuel 2022, 320, 123944.
48. Singh, A.; Nanda, S.; Guayaquil-Sosa, J.F.; Berruti, F. Pyrolysis of Miscanthus and characterization of value-added bio-oil and biochar products. Can. J. Chem. Eng. 2021, 99, S55–S68.
49. Khan, I.U.; Chen, H.; Yan, Z.; Chen, J. Extraction and quality evaluation of biodiesel from six familiar non-edible plants seeds. Processes 2021, 9, 840.
50. Kumar, A.; Samadder, S.R. An empirical model for prediction of household solid waste generation rate—A case study of Dhanbad, India. Waste Manag. 2017, 68, 3–15.
51. Nanda, S.; Berruti, F. Municipal solid waste management and landfilling technologies: A review. Environ. Chem. Lett. 2021, 19, 1433–1456.
52. Rajendran, N.; Gurunathan, B.; Han, J.; Krishna, S.; Ananth, A.; Venugopal, K.; Priyanka, R.S. Recent advances in valorization of organic municipal waste into energy using biorefinery approach, environment and economic analysis. Bioresour. Technol. 2021, 337, 125498.
53. Gunarathne, V.; Ashiq, A.; Ramanayaka, S.; Wijekoon, P.; Vithanage, M. Biochar from municipal solid waste for resource recovery and pollution remediation. Environ. Chem. Lett. 2019, 17, 1225–1235.
54. Fazeli, A.; Bakhtvar, F.; Jahanshaloo, L.; Sidik, N.A.C.; Bayat, A.E. Malaysia’s stand on municipal solid waste conversion to energy: A review. Renew. Sustain. Energy Rev. 2016, 58, 1007–1016.
55. Ouda, O.K.; Cekirge, H.M.; Raza, S.A. An assessment of the potential contribution from waste-to-energy facilities to electricity demand in Saudi Arabia. Energy Convers. Manag. 2013, 75, 402–406.
56. Clavier, K.A.; Paris, J.M.; Ferraro, C.C.; Townsend, T.G. Opportunities and challenges associated with using municipal waste incineration ash as a raw ingredient in cement production—A review. Resour. Conserv. Recycl. 2020, 160, 104888.
57. Mishra, S.; Tiwary, D.; Ohri, A.; Agnihotri, A.K. Impact of municipal solid waste landfill leachate on groundwater quality in Varanasi, India. Groundw. Sustain. Dev. 2019, 9, 100230.
58. Nanda, S.; Isen, J.; Dalai, A.K.; Kozinski, J.A. Gasification of fruit wastes and agro-food residues in supercritical water. Energy Convers. Manag. 2016, 110, 296–306.
59. Kiran, E.U.; Trzcinski, A.P.; Ng, W.J.; Liu, Y. Bioconversion of food waste to energy: A review. Fuel 2014, 134, 389–399.
60. Ren, Y.; Wang, C.; He, Z.; Qin, Y.; Li, Y.Y. Enhanced biomethanation of lipids by high-solid co-digestion with food waste: Biogas production and lipids degradation demonstrated by long-term continuous operation. Bioresour. Technol. 2022, 348, 126750.
61. Kiran, E.U.; Liu, Y. Bioethanol production from mixed food waste by an effective enzymatic pretreatment. Fuel 2015, 159, 463–469.
62. Qin, Z.; Duns, G.J.; Pan, T.; Xin, F. Consolidated processing of biobutanol production from food wastes by solventogenic Clostridium sp. strain HN4. Bioresour. Technol. 2018, 264, 148–153.
63. Yasin, N.H.M.; Mumtaz, T.; Hassan, M.A.; Rahman, N.A. Food waste and food processing waste for biohydrogen production: A review. J. Environ. Manag. 2013, 130, 375–385.
64. Patra, B.R.; Nanda, S.; Dalai, A.K.; Meda, V. Slow pyrolysis of agro-food wastes and physicochemical characterization of biofuel products. Chemosphere 2021, 285, 131431.
65. Patra, B.R.; Nanda, S.; Dalai, A.K.; Meda, V. Taguchi-based process optimization for activation of agro-food waste biochar and performance test for dye adsorption. Chemosphere 2021, 285, 131531.
66. Nguyen, B.T.; Trinh, N.N.; Bach, Q.V. Methane emissions and associated microbial activities from paddy salt-affected soil as influenced by biochar and cow manure addition. Appl. Soil Ecol. 2020, 152, 103531.
67. Khoshnevisan, B.; Duan, N.; Tsapekos, P.; Awasthi, M.K.; Liu, Z.; Mohammadi, A.; Angelidaki, I.; Tsang, D.C.; Zhang, Z.; Pan, J.; et al. A critical review on livestock manure biorefinery technologies: Sustainability, challenges, and future perspectives. Renew. Sustain. Energy Rev. 2021, 135, 110033.
68. Yao, Y.; Huang, G.; An, C.; Chen, X.; Zhang, P.; Xin, X.; Shen, J.; Agnew, J. Anaerobic digestion of livestock manure in cold regions: Technological advancements and global impacts. Renew. Sustain. Energy Rev. 2020, 119, 109494.
69. Dareioti, M.A.; Vavouraki, A.I.; Tsigkou, K.; Zafiri, C.; Kornaros, M. Dark fermentation of sweet sorghum stalks, cheese whey and cow manure mixture: Effect of pH, pretreatment and organic load. Processes 2021, 9, 1017.
70. Yan, Q.; Liu, X.; Wang, Y.; Li, H.; Li, Z.; Zhou, L.; Qu, Y.; Li, Z.; Bao, X. Cow manure as a lignocellulosic substrate for fungal cellulase expression and bioethanol production. AMB Exp. 2018, 8, 190.
71. Su, G.; Ong, H.C.; Zulkifli, N.W.M.; Ibrahim, S.; Chen, W.H.C.; Chong, C.T.; Ok, Y.S. Valorization of animal manure via pyrolysis for bioenergy: A review. J. Clean. Prod. 2022, 343, 130965.
72. Liu, Q.; Xua, R.; Yan, C.; Han, L.; Lei, H.; Ruan, R.; Zhang, X. Fast hydrothermal co-liquefaction of corn stover and cow manure for biocrude and hydrochar production. Bioresour. Technol. 2021, 340, 125630.
73. Nanda, S.; Dalai, A.K.; Gökalp, I.; Kozinski, J.A. Valorization of horse manure through catalytic supercritical water gasification. Waste Manag. 2016, 52, 147–158.
74. Itoh, T.; Iwabuchi, K.; Maemoku, N.; Sasaki, I.; Taniguro, K. A new torrefaction system employing spontaneous self-heating of livestock manure under elevated pressure. Waste Manag. 2019, 85, 66–72.
75. Cheong, D.Y.; Harvey, J.T.; Kim, J.; Lee, C. Improving biomethanation of chicken manure by co-digestion with ethanol plant effluent. Int. J. Env. Res. Public Health 2019, 16, 5023.
76. Yong, T.L.K.; Matsumura, Y. Catalytic gasification of poultry manure and eucalyptus wood mixture in supercritical water. Ind. Eng. Chem. Res. 2012, 51, 5685–5690.
77. Sarker, T.R.; Nanda, S.; Dalai, A.K.; Meda, V. A review of torrefaction technology for upgrading lignocellulosic biomass to solid biofuels. BioEnergy Res. 2021, 14, 645–669. [Google Scholar] [CrossRef]
78. Basu, P.; Sadhukhan, A.K.; Gupta, P.; Rao, S.; Dhungana, A.; Acharya, B. An experimental and theoretical investigation on torrefaction of a large wet wood particle. Bioresour. Technol. 2014, 159, 215–222.
79. Chen, W.H.; Peng, J.; Bi, X.T. A state-of-the-art review of biomass torrefaction, densification and applications. Renew. Sustain. Energy Rev. 2015, 44, 847–866.
80. Acharya, B.; Dutta, A.; Minaret, J. Review on comparative study of dry and wet torrefaction. Sustain. Energy Technol. Assess. 2015, 12, 26–37.
81. Osman WNAW, Rosli MH, Mazli WNA, Samsuri S. Comparative review of biodiesel production and purification. Carbon Capture Science & Technology. 2024;13:100264. doi:10.1016/j.ccst.2024.100264
82. Zhang C, Singh RP, Yadav P, et al. Recent advances in biotechnology and bioengineering for efficient microalgal biofuel production. Fuel Processing Technology. 2025;270:108199. doi:10.1016/j.fuproc.2025.108199
83. Ahmed N, Shakoor N. Advancing Agriculture through IoT, Big Data, and AI: A Review of Smart Technologies Enabling Sustainability. Smart Agricultural Technology. February 2025:100848. doi:10.1016/j.atech.2025.100848
84. Shah V, Patel N, Prajapati P, Jouhara H. Unlocking biogas potential: A comprehensive study on pretreatment techniques of organic substrate for enhanced anaerobic digestion. Energy. 2025;335:138244. doi:10.1016/j.energy.2025.138244
85. Chowdhury P, Mahi NA, Yeassin R, Chowdhury NUR, Farrok O. Biomass to biofuel: Impacts and mitigation of environmental, health, and socioeconomic challenges. Energy Conversion and Management X. 2025;25:100889. doi:10.1016/j.ecmx.2025.100889
86. Sofán-Germán SJ, Doria-Oviedo ME, Rhenals-Julio JD, Mendoza-Fandiño JM. Life Cycle Assessment of Biomass Waste and Coal Co-Firing: Advancing Circular Economy in Energy Production. Recycling. 2025; 10(4):151. https://doi.org/10.3390/recycling10040151
87. Kaur S, Kumar R, Singh K, Singh S. Systematic review of hydrogen, biomass, biogas, and solar photovoltaics in hybrid renewable energy systems: Advancements, challenges, and future directions. International Journal of Hydrogen Energy. 2025;137:160-189. doi:10.1016/j.ijhydene.2025.04.525
88. Alcocer-García H, Sánchez-Ramírez E, García-García E, Ramírez-Márquez C, Ponce-Ortega JM. Unlocking the Potential of Biomass Resources: A Review on Sustainable Process Design and Intensification. Resources. 2025; 14(9):143. https://doi.org/10.3390/resources14090143
89. El-Fawal EM, El Naggar AMA, El-Zahhar AA, Alghandi MM, Morshedy AS, El Sayed HA, Mohammed AEME. Biofuel production from waste residuals: comprehensive insights into biomass conversion technologies and engineered biochar applications. RSC Adv. 2025 Apr 22;15(15):11942-11974. doi: 10.1039/d5ra00857c. Erratum in: RSC Adv. 2025 May 16;15(21):16468. doi: 10.1039/d5ra90054a.
90. Saravanan A, Ragini YP, Karishma S, Hemavathy RV, Jyotsna M. A review on advancing sustainable energy: The role of biomass and bioenergy in a circular economy. Sustainable Futures. 2025;10:100835. doi:10.1016/j.sftr.2025.100835
91. Llanos-Lizcano R, Senila L, Modoi OC. Evaluation of Biochemical Methane Potential and Kinetics of Organic Waste Streams for Enhanced Biogas Production. Agronomy. 2024; 14(11):2546. https://doi.org/10.3390/agronomy14112546
92. Sahith N V, J AK, Sruthi S V. Microbial biofuels: a comprehensive review of advances toward sustainable energy and environmental mitigation. International Journal of Ambient Energy. 2025;46(1). doi:10.1080/01430750.2025.2571520
93. Nabaterega R, Vesuwe RN, Iorhemen OT, Thring RW. Biodiesel production unpacked: Data-driven analysis of key operational factors. Biomass and Bioenergy. 2025;205:108457. doi:10.1016/j.biombioe.2025.108457
94. Naseef HH, Tulaimat RH. Transesterification and esterification for biodiesel production: A comprehensive review of catalysts and palm oil feedstocks. Energy Conversion and Management X. February 2025:100931. doi:10.1016/j.ecmx.2025.100931
95. Babu KKBS, Nataraj M, Tayappa M, Vyas Y, Mishra RK, Acharya B. Production of biochar from waste biomass using slow pyrolysis: Studies of the effect of pyrolysis temperature and holding time on biochar yield and properties. Materials Science for Energy Technologies. 2024;7:318-334. doi:10.1016/j.mset.2024.05.002
96. Gao Y, Wang M, Raheem A, et al. Syngas Production from Biomass Gasification: Influences of Feedstock Properties, Reactor Type, and Reaction Parameters. ACS Omega. 2023;8(35):31620-31631. doi:10.1021/acsomega.3c03050
97. Shrestha S, Pandey R, Aryal N, Lohani SP. Recent advances in co-digestion conjugates for anaerobic digestion of food waste. Journal of Environmental Management. 2023;345:118785. doi:10.1016/j.jenvman.2023.118785
98. Kazmi A, Sultana T, Ali A, Nijabat A, Li G, Hou H. Innovations in bioethanol production: A comprehensive review of feedstock generations and technology advances. Energy Strategy Reviews. 2025;57:101634. doi:10.1016/j.esr.2024.101634
99. Farouk SM, Tayeb AM, Abdel-Hamid SMS, Osman RM. Recent advances in transesterification for sustainable biodiesel production, challenges, and prospects: a comprehensive review. Environmental Science and Pollution Research. 2024;31(9):12722-12747. doi:10.1007/s11356-024-32027-4
100. Liu Y, Sun Y, Wu X, et al. In-situ hydrodeoxygenation of a lignin-derived monomer using Ar dielectric barrier discharge plasma: From conversion performance to mechanism analysis. Journal of the Energy Institute. 2025;124:102344. doi:10.1016/j.joei.2025.102344
101. Prestipino M, Corigliano O, Galvagno A, Piccolo A, Fragiacomo P. Exploring the potential of wet biomass gasification with SOFC and ICE cogeneration technologies: process design, simulation and comparative thermodynamic analysis. Applied Energy. 2025;392:125998. doi:10.1016/j.apenergy.2025.125998
102. Song YJ, Oh KS, Lee B, Pak DW, Cha JH, Park JG. Characteristics of Biogas Production from Organic Wastes Mixed at Optimal Ratios in an Anaerobic Co-Digestion Reactor. Energies. 2021;14(20):6812. doi:10.3390/en14206812
103. Tsegaye KN, Alemnew M, Berhane N. Saccharomyces cerevisiae for lignocellulosic ethanol production: a look at key attributes and genome shuffling. Frontiers in Bioengineering and Biotechnology. 2024;12. doi:10.3389/fbioe.2024.1466644
104. Monika N, Banga S, Pathak VV. Biodiesel production from waste cooking oil: A comprehensive review on the application of heterogenous catalysts. Energy Nexus. 2023;10:100209. doi:10.1016/j.nexus.2023.100209
105. Parvari E, Mahajan D, Hewitt EL. A Review of Biomass Pyrolysis for Production of Fuels: Chemistry, Processing, and Techno-Economic Analysis. Biomass. 2025; 5(3):54. https://doi.org/10.3390/biomass5030054
106. Natarajan A, Venugopal D, Thangavelu L. Investigation of biomass gasification simulation using air, steam and oxygen as gasifying agent. Thermal Science. 2022;26(6 part B):5109-5119. doi:10.2298/tsci220207092n
107. Sarwar H, Vuppaladadiyam A, Venkatachalapati A, et al. Pre-treatment of organic biomass in the context of stand-alone and integrated anaerobic digestion–pyrolysis for enhanced product recovery: A critical review of challenges and opportunities. Biomass and Bioenergy. 2025;204:108386. doi:10.1016/j.biombioe.2025.108386
108. Kataya G, Cornu D, Bechelany M, Hijazi A, Issa M. Biomass Waste Conversion Technologies and Its Application for Sustainable Environmental Development—A Review. Agronomy. 2023; 13(11):2833. https://doi.org/10.3390/agronomy13112833
