Advanced Bioenergy and Biofuel Technologies

Topic Information

Dear Colleagues,

We are inviting submissions to a Topic "Advanced Bioenergy and Biofuel Technologies". Biomass-derived fuels offer promising solutions for reducing GHG emissions while enhancing energy security. Recent advancements in biofuel technologies such as pyrolysis and hydrothermal liquefaction have improved production efficiency, fuel stability, and the valorization of agricultural and forestry residues, municipal solid waste, and algae-based feedstocks.

In particular, torrefied biomass and biocarbon are gaining attention as renewable energy sources with high energy density and enhanced properties. Additionally, sustainable aviation fuel (SAF) and bio-marine fuels are emerging as key solutions for decarbonizing the aviation and maritime industries. However, ensuring a stable and sustainable supply of biomass feedstock remains a critical challenge.

This Topic seeks innovative research on the latest advancements in bioenergy and biofuels. Topics of interest include, but are not limited to, biomass pre-treatment, biofuel production and upgrading (torrefied biomass, biocarbon, SAF, bio-marine fuels, biogas, etc.), feedstock sustainability, waste-to-energy strategies, and life-cycle assessment. We welcome original research, reviews, and case studies that contribute to the sustainable development of bioenergy and biofuel technologies.

Dr. Jiho Yoo
Dr. Hokyung Choi
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Biomass biomass	-	4.2	2021	19.8 Days	CHF 1000	Submit
Catalysts catalysts	4.0	7.6	2011	16.6 Days	CHF 2200	Submit
Energies energies	3.2	7.3	2008	16.2 Days	CHF 2600	Submit
Processes processes	2.8	5.5	2013	16 Days	CHF 2400	Submit
Sustainability sustainability	3.3	7.7	2009	19.3 Days	CHF 2400	Submit
Molecules molecules	4.6	8.6	1996	16.1 Days	CHF 2700	Submit

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Published Papers (5 papers)

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All Biomass Catalysts Energies Processes Sustainability Molecules

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22 pages, 2265 KB  

Open AccessArticle

Utilization of Low-Viscosity Sustainable Quaternary Microemulsification Fuels Containing Waste Frying Oil–Diesel Fuel–Bio-Alcohols in a Turbocharged-CRDI Diesel Engine

by Huseyin Sanli

Sustainability 2025, 17(19), 8835; https://doi.org/10.3390/su17198835 - 2 Oct 2025

Abstract

In this study, low-viscosity (<5 mm²·s⁻¹, fits European Biodiesel Standard-EN 14214) quaternary microemulsification fuels were developed and tested in a CRDI diesel engine to evaluate their effects on engine performance, injection, combustion, and emission characteristics. The fuels were formulated [...] Read more.

In this study, low-viscosity (<5 mm²·s⁻¹, fits European Biodiesel Standard-EN 14214) quaternary microemulsification fuels were developed and tested in a CRDI diesel engine to evaluate their effects on engine performance, injection, combustion, and emission characteristics. The fuels were formulated using 50% petro-diesel, 30% waste frying oil (without converting biodiesel), and a combination of 10% n-butanol with either 10% methanol or 10% ethanol. Engine tests were conducted at constant speed of 2000 rpm and five different engine loads. The results indicated that both microemulsified fuels exhibited increased brake specific fuel consumption by about 20% and brake specific energy consumption by around 8% compared to petro-diesel, while thermal efficiency decreased by about 8%. Injection timing for both pilot and main injections occurred earlier with the emulsification fuels, and higher injection amount and injection rate values were observed at all loads. As engine load increased, the peak cylinder pressures of the emulsified fuels surpassed those of petro-diesel, although the crank angles at which these peak values were attained were similar. The combustion duration was shorter for both quaternary fuels, with similar maximum pressure rise rates to petro-diesel. Emulsification fuels caused higher exhaust emissions (especially THC) and this difference increased with increasing load. When comparing two formulations, the methanol-containing fuel demonstrated slightly better results than the ethanol-containing blend. These findings suggest that microemulsified fuels containing bio-alcohols and waste frying oil can be sustainable fuel alternatives for partial petro-diesel substitution if the injection settings are adapted in accordance with the properties of these fuels. Full article

(This article belongs to the Topic Advanced Bioenergy and Biofuel Technologies)

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28 pages, 4768 KB  

Open AccessArticle

Biogas and Hydrogen Production from Waste Biomass via Dark Fermentation Evaluating VFAs, COD, and HRT for Process Optimization

by Hoe-Gil Lee and Zachary Dulany

Biomass 2025, 5(3), 57; https://doi.org/10.3390/biomass5030057 - 18 Sep 2025

Cited by 1 | Viewed by 276

Abstract

Biomass energy transforms waste into biofuels and supports water purification. This study examines enhanced hydrogen production via dark fermentation, tracking volatile fatty acids (VFAs), chemical oxygen demand (COD), carbohydrates, and hydraulic retention time (HRT) to optimize biogas yield and quality. Investigations into acidogenesis [...] Read more.

Biomass energy transforms waste into biofuels and supports water purification. This study examines enhanced hydrogen production via dark fermentation, tracking volatile fatty acids (VFAs), chemical oxygen demand (COD), carbohydrates, and hydraulic retention time (HRT) to optimize biogas yield and quality. Investigations into acidogenesis and acetogenesis explore methods for breaking down long-chain VFAs into short-chain VFAs, which are critical for efficient hydrogen generation. Testing and analysis of VFAs, carbonates, COD, and HRT provide insights into bacterial activity that drives hydrogen production. The main VFAs produced were acetic, propionic, and butyric acids. DF1 and DF2 primarily generated acetic acid, consistent with cheese whey (CW)-based fermentations. DF1.1, using 5× diluted CW and a 30:70 inoculum-to-substrate ratio (I2SR), exhibited elevated butyric acid levels, similar to those observed with food waste. The first dark fermentation process (DF1) initially showed effective carbohydrate metabolism but later experienced spikes in succinic and lactic acids, which reduced hydrogen production. In contrast, the second dark fermentation process (DF2) maintained low lactic acid levels and increased acetate concentrations, indicating improved system performance. DF1.1 also demonstrated stable VFA production and lactic acid reduction. Greater CW dilution, higher initial pH, and increased HRT were key factors in minimizing acidification and enhancing hydrogen-producing pathways. Full article

(This article belongs to the Topic Advanced Bioenergy and Biofuel Technologies)

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17 pages, 1924 KB  

Open AccessArticle

Conversion of Furfural as a Bio-Oil Model Compound over Calcium-Based Materials as Sacrificial Low-Cost Catalysts for Bio-Oil Upgrading

by Moritz Böhme, Peter A. Jensen, Martin Høj, Brian B. Hansen, Magnus Z. Stummann and Anker D. Jensen

Catalysts 2025, 15(6), 554; https://doi.org/10.3390/catal15060554 - 3 Jun 2025

Viewed by 770

Abstract

The stabilization and upgrading of biomass and waste-derived pyrolysis oils requires development of reliable, active and low-cost upgrading catalysts. Basic natural materials can act as such catalysts and convert reactive oxygenates present in biomass pyrolysis oils. The conversion of furfural as a model [...] Read more.

The stabilization and upgrading of biomass and waste-derived pyrolysis oils requires development of reliable, active and low-cost upgrading catalysts. Basic natural materials can act as such catalysts and convert reactive oxygenates present in biomass pyrolysis oils. The conversion of furfural as a model compound has been conducted in an autoclave reactor at 200 °C to 300 °C using different calcium-based materials. CaCO₃, Ca(OH)₂, CaO, cement raw meal (CRM) and calcined cement raw meal (cCRM) were screened for their catalytic activity and characterized using X-ray powder diffraction (XRD) and X-ray fluorescence (XRF), nitrogen physisorption, carbon dioxide temperature programmed desorption (CO₂-TPD) and thermogravimetric analysis (TGA). CaCO₃ and CRM had low basicity and showed no catalytic activity at 200 to 300 °C. Notably, 90% conversion of furfural was achieved at 200 °C using Ca(OH)₂ with products being mostly furfural di- and trimers. For the basic CaO and cCRM, a temperature of 250 °C or above caused rapid polymerization of furfural. The proposed mechanism follows the Cannizzaro reaction of furfural, catalyzed by basic sites, polymerization of furfuryl alcohol, decarboxylation of furoic acid and decarbonylation of furfural, releasing CO, CO₂ and H₂O. Calcined cement raw meal showed the most promise for application as low-cost, sacrificial, basic catalyst. Full article

(This article belongs to the Topic Advanced Bioenergy and Biofuel Technologies)

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14 pages, 3084 KB  

Open AccessArticle

Catalytic Hydrodeoxygenation of Pyrolysis Volatiles from Pine Nut Shell over Ni-V Bimetallic Catalysts Supported on Zeolites

by Yujian Wu, Xiwei Xu, Xudong Fan, Yan Sun, Ren Tu, Enchen Jiang, Qing Xu and Chunbao Charles Xu

Catalysts 2025, 15(5), 498; https://doi.org/10.3390/catal15050498 - 20 May 2025

Viewed by 641

Abstract

Bio-oil is a potential source for the production of alternative fuels and chemicals. In this work, Ni-V bimetallic zeolite catalysts were synthesized and evaluated in in situ catalytic hydrodeoxygenation (HDO) of pyrolysis volatiles of pine nut shell for upgraded bio-oil products. The pH [...] Read more.

Bio-oil is a potential source for the production of alternative fuels and chemicals. In this work, Ni-V bimetallic zeolite catalysts were synthesized and evaluated in in situ catalytic hydrodeoxygenation (HDO) of pyrolysis volatiles of pine nut shell for upgraded bio-oil products. The pH and lower heating value (LHV) of the upgraded bio-oil products were improved by in situ catalytic HDO, while the moisture content and density of the oil decreased. The O/C ratio of the upgraded bio-oil products decreased significantly, and the oxygenated compounds in the pyrolysis volatiles were converted efficiently via deoxygenation over Ni-V zeolite catalysts. The highest HDO activity was obtained with NiV/MesoY, where the obtained bio-oil had the lowest O/C atomic ratio (0.27), a higher LHV (27.03 MJ/kg) and the highest selectivity (19.6%) towards target arenes. Owing to the more appropriate pore size distribution and better dispersion of metal active sites, NiV/MesoY enhanced the transformation of reacting intermediates, obtaining the dominant products of phenols and arenes. A higher HDO temperature improved the catalytic activity of pyrolysis volatiles to form more deoxygenated arenes. Higher Ni loading could generate more metal active sites, thus promoting the catalyst’s HDO activity for pyrolysis volatiles. This study contributes to the development of cost-efficient and eco-friendly HDO catalysts, which are required for producing high-quality biofuel products. Full article

(This article belongs to the Topic Advanced Bioenergy and Biofuel Technologies)

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22 pages, 1205 KB  

Open AccessReview

Integrated Approach for Biomass Conversion Using Thermochemical Routes with Anaerobic Digestion and Syngas Fermentation

by Dolores Hidalgo, Ana Urueña, Jesús M. Martín-Marroquín and David Díez

Sustainability 2025, 17(8), 3615; https://doi.org/10.3390/su17083615 - 16 Apr 2025

Cited by 7 | Viewed by 1853

Abstract

This review focuses on the integration of thermochemical and biochemical processes as a transformative approach to biomass conversion. By combining technologies such as anaerobic digestion, hydrothermal liquefaction, pyrolysis, and syngas fermentation, this review highlights how hybrid systems maximize resource recovery and improve energy [...] Read more.

This review focuses on the integration of thermochemical and biochemical processes as a transformative approach to biomass conversion. By combining technologies such as anaerobic digestion, hydrothermal liquefaction, pyrolysis, and syngas fermentation, this review highlights how hybrid systems maximize resource recovery and improve energy efficiency. Key examples include the use of digestate from anaerobic digestion as a feedstock for pyrolysis or hydrothermal carbonization, enhancing biochar and hydrochar production while improving nutrient recycling. Similarly, the integration of syngas fermentation with gasification demonstrates how thermochemical products can be further valorized into biofuels under milder biochemical conditions. This review also addresses the reuse of by-products, such as the aqueous phase from hydrothermal processes, in nutrient recovery and algae cultivation, showcasing the circular potential of these systems. By emphasizing the technical and economic synergies of integrating diverse technologies, this paper outlines a clear pathway for industrial-scale adoption, contributing to sustainable energy production and reduced greenhouse gas emissions. Full article

(This article belongs to the Topic Advanced Bioenergy and Biofuel Technologies)

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