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Potentials of Sustainable Aviation Fuel Production from Biomass and Waste: How Australia’s Sugar Industry Can Become a Successful Global Example
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Pineapple Waste Biorefinery: An Integrated System for Production of Biogas and Marketable Products in South Africa
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Modified Hydrothermal Pretreatment Conditions Enhance Alcohol Solubility of Lignin from Wheat Straw Biorefining
Journal Description
Biomass
Biomass
is an international, peer-reviewed, open access journal on biomass conversion and biorefinery published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus, EBSCO, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 19.8 days after submission; acceptance to publication is undertaken in 3.7 days (median values for papers published in this journal in the first half of 2025).
- Journal Rank: CiteScore - Q1 (Forestry)
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Latest Articles
Resource Recovery from Green Tide Biomass: Sustainable Cascading Biorefinery Strategies for Ulva spp.
Biomass 2025, 5(3), 41; https://doi.org/10.3390/biomass5030041 - 2 Jul 2025
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This review examines sustainable cascading biorefinery strategies for the green alga Ulva, which is globally prevalent in eutrophic marine waters and often forms extensive “green tides.” These blooms cause substantial environmental and economic damage to coastal communities. The primary target products within
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This review examines sustainable cascading biorefinery strategies for the green alga Ulva, which is globally prevalent in eutrophic marine waters and often forms extensive “green tides.” These blooms cause substantial environmental and economic damage to coastal communities. The primary target products within an Ulva biorefinery typically encompass salts, lipids, proteins, cellulose, and ulvan. Each of these components possesses unique properties and diverse applications, contributing to the economic robustness of the biorefinery. Salts can be repurposed for agricultural or even human consumption. Lipids offer high-value applications in nutraceuticals and animal feed. Proteins present significant potential as plant-based nutritional supplements. Cellulose can be transformed into various advanced materials. Finally, ulvan, a polyanionic oligosaccharide unique to Ulva, holds promise due to its distinct properties, particularly in the biomedical field. Furthermore, state-of-the-art chemical modifications of ulvan are presented with the aim of tailoring its properties and broadening its potential applications. Future research should prioritize optimizing these integrated extraction and fractionation processes. Furthermore, a multi-product biorefining approach, integrated with robust Life Cycle Assessment studies, is vital for transforming this environmental challenge into a significant opportunity for sustainable resource valorization and economic growth.
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Open AccessArticle
Production, Characterization, and Application of KOH-Activated Biochar from Rice Straw for Azo Dye Adsorption
by
Megananda Eka Wahyu, Damayanti Damayanti and Ho Shing Wu
Biomass 2025, 5(3), 40; https://doi.org/10.3390/biomass5030040 - 1 Jul 2025
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This study explored the production and activation of biochar from rice straw residue for dye adsorption applications. Rice straw, a widely available but underutilized biomass, was processed to isolate lignin and generate biochar through pyrolysis at 450 °C and 550 °C. Activation using
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This study explored the production and activation of biochar from rice straw residue for dye adsorption applications. Rice straw, a widely available but underutilized biomass, was processed to isolate lignin and generate biochar through pyrolysis at 450 °C and 550 °C. Activation using chemical agents (e.g., KOH and NaOH) was performed to enhance surface area and porosity. Among the tested conditions, KOH activation at a char-to-agent ratio of 1:3 produced activated carbon at 800 °C with the highest BET surface area (835.2 m2/g), and high fixed carbon (44.4%) after HCl washing. Thermogravimetric analysis was used to investigate pyrolysis kinetics, with activation energies determined using the Kissinger, Flynn–Wall–Ozawa, and Kissinger–Akahira–Sunose models. The brown solid showed a higher activation energy (264 kJ/mol) compared to isolated lignin (194 kJ/mol), indicating that more energy is required for decomposition. The AC was evaluated for the adsorption of methylene blue (MB) and methyl orange (MO) from aqueous solutions. Both dyes followed the Langmuir isotherm model, indicating that monolayer adsorption occurred. The maximum adsorption capacities reached 222 mg/g for MB and 244 mg/g for MO at 303 K, with higher values at elevated temperatures. Adsorption followed a pseudo-second-order kinetic model and was governed by a physisorption mechanism, as supported by thermodynamic analysis (ΔH < 20 kJ/mol and Ea < 40 kJ/mol). These findings demonstrate that KOH-activated biochar from rice straw residue is a high-performance, low-cost adsorbent for dye removal, contributing to sustainable biomass utilization and wastewater treatment.
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Open AccessArticle
Biochar-Enriched Organic Fertilizers from Sugar Industry Waste: A Sustainable Approach to Soil Fertility and Crop Growth
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Helitha Nilmalgoda, Jayashan Bandara, Isuru Wijethunga, Asanga Ampitiyawatta and Kaveenga Koswattage
Biomass 2025, 5(3), 39; https://doi.org/10.3390/biomass5030039 - 1 Jul 2025
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This study investigates biochar-enriched organic fertilizers made from bagasse, ash, spent wash, and cane tops, assessing their impact on corn growth over 45 days. A randomized complete block design with three replicates was used, testing six formulations with biochar levels at 0%, 10%,
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This study investigates biochar-enriched organic fertilizers made from bagasse, ash, spent wash, and cane tops, assessing their impact on corn growth over 45 days. A randomized complete block design with three replicates was used, testing six formulations with biochar levels at 0%, 10%, and 20%, along with soil-only and commercial fertilizer controls. Treatments T5 (bagasse + ash + spent wash + cane tops), T11 (T5 + 10% biochar), and T17 (T5 + 20% biochar) showed the best results for plant height, leaf development, and biomass production, with T17 performing the best for growth, biomass, and girth. The biochar in T17 had a pH of 9.37 ± 0.16, 18.00 ± 1.25% ash content, and a surface area of 144.58 m2/g. Nutrient analysis of the compost showed 2.85% potassium, 1.12% phosphorus, 1.85% nitrogen, 4.1% calcium, 0.23% magnesium, and 130 mg/kg zinc. The elemental composition was 68.50% carbon, 4.50% hydrogen, 6.00% nitrogen, and 25.30% oxygen, with 85.00% total organic carbon (TOC). This study concludes that T17 is the most effective formulation, offering both environmental and financial benefits, with composting potentially generating $11.16 million in profit, compared to the $19.32 million spent annually on waste management in Sri Lanka’s sugar industry.
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Open AccessEditorial
Updating the Aims and Scope of BIOMASS: Novel Endeavors and Perspectives
by
Dimitris P. Makris
Biomass 2025, 5(3), 38; https://doi.org/10.3390/biomass5030038 - 23 Jun 2025
Abstract
Biomass was launched in 2021, aiming at providing an open access reservoir of knowledge pertaining to the field of biomass and its harnessing [...]
Full article
Open AccessReview
Catalytic Biomass Gasification for Syngas Production: Recent Progress in Tar Reduction and Future Perspectives
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Gitanjali Jothiprakash, Prabha Balasubramaniam, Senthilarasu Sundaram and Desikan Ramesh
Biomass 2025, 5(3), 37; https://doi.org/10.3390/biomass5030037 - 20 Jun 2025
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Biomass gasification is an effective process for converting organic wastes into syngas. Syngas is a biofuel that possesses several potential applications in the energy sector. However, the major bottleneck for the commercialization of this technology is tar production in biomass gasification, which affects
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Biomass gasification is an effective process for converting organic wastes into syngas. Syngas is a biofuel that possesses several potential applications in the energy sector. However, the major bottleneck for the commercialization of this technology is tar production in biomass gasification, which affects gasifier performance and syngas yield/quality. Tar can be destructed by adopting in situ or ex situ modes of utilizing catalysts in biomass gasification. The added advantage of tar reduction is enhanced syngas energy content. Despite their advantages, catalysts face challenges such as high costs, declining performance over time, and difficulties in regeneration and recycling. Deactivation can also occur due to poisoning, fouling, and carbon buildup. While some natural materials have been tested as alternative materials, the financial sustainability and affordability of catalysts remain crucial for large-scale syngas production. This paper offers an overview of tar reduction strategies and the role of various catalysts in the gasification process and future perspectives on catalyst development for biomass gasification.
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Open AccessArticle
Characterization of Liquefaction Products from Lignocellulosic and Aquatic Biomass
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Telma Moreira, Maria Margarida Mateus, Luís C. Duarte and Maria Joana Neiva Correia
Biomass 2025, 5(2), 36; https://doi.org/10.3390/biomass5020036 - 13 Jun 2025
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Biomass liquefaction is a promising thermochemical route to convert lignocellulosic residues into bio-oil. This study evaluates the liquefaction behavior of 13 biomasses with varying particle sizes (0.3–2.0 mm) and moisture contents (5–11%) under mild solvolysis conditions. High-performance liquid chromatography (HPLC-RID) and thermogravimetric analysis
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Biomass liquefaction is a promising thermochemical route to convert lignocellulosic residues into bio-oil. This study evaluates the liquefaction behavior of 13 biomasses with varying particle sizes (0.3–2.0 mm) and moisture contents (5–11%) under mild solvolysis conditions. High-performance liquid chromatography (HPLC-RID) and thermogravimetric analysis (TGA) were used to characterize bio-oil composition and biomass properties, respectively. Maximum conversion (72%) was achieved for Miscanthus, while Ulva lactuca reached only 23% due to its low carbohydrate content. Hemicellulose-rich feedstocks showed higher yields, whereas high lignin content generally reduced conversion. Furfural was the main compound identified in the aqueous phase (up to 51 g/L), reflecting extensive pentose degradation. Laboratory and industrial-scale liquefaction of cork and eucalyptus revealed scale-dependent differences. Industrial cork bio-oil showed increased xylose (0.70 g/L) and furfural (0.40 g/L), while industrial eucalyptus exhibited elevated levels of acetic (0.46 g/L) and formic acids (0.71 g/L), indicating enhanced deacetylation and demethoxylation reactions. These findings offer valuable insights for optimizing feedstock selection and process conditions in biomass liquefaction. The valorization of lignocellulosic residues into bio-oil contributes to the development of scalable, low-carbon technologies aligned with circular economy principles and bio-based industrial strategies.
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Open AccessArticle
One-Pot Microwave-Assisted Synthesis of Fluorescent Carbon Dots from Tomato Industry Residues with Antioxidant and Antibacterial Activities
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Patrícia D. Barata, Alexandra I. Costa, Sónia Martins, Magda C. Semedo, Bruno G. Antunes and José V. Prata
Biomass 2025, 5(2), 35; https://doi.org/10.3390/biomass5020035 - 10 Jun 2025
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Tomato waste (TW) was employed as a sustainable source for the synthesis of fluorescent carbon dots (CDs) via a microwave-assisted hydrothermal carbonization (Mw-HTC) method, aiming at its valorization. Several amines were used as nitrogen additives to enhance the fluorescence quantum yield (QY) of
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Tomato waste (TW) was employed as a sustainable source for the synthesis of fluorescent carbon dots (CDs) via a microwave-assisted hydrothermal carbonization (Mw-HTC) method, aiming at its valorization. Several amines were used as nitrogen additives to enhance the fluorescence quantum yield (QY) of CDs, and a set of reaction conditions, including additive/TW mass ratio (0.04–0.32), dwell time (15–60 min), and temperature (200–230 °C) of the HTC process, were scrutinized. The structural analysis of the tomato waste carbon dots (TWCDs) was undertaken by FTIR and 1H NMR techniques, revealing their most relevant features. In solid state, transmission electron microscopy (TEM) analysis showed the presence of nearly spherical nanoparticles with an average lateral size of 8.1 nm. Likewise, the topographical assessment by atomic force microscopy (AFM) also indicated particles’ heights between 3 and 10 nm. Their photophysical properties, revealed by UV–Vis, steady-state, and time-resolved fluorescence spectroscopies, are fully discussed. Higher photoluminescent quantum yields (up to 0.08) were attained when the biomass residues were mixed with organic aliphatic amines during the Mw-HTC process. Emission tunability is a characteristic feature of these CDs, which display an intensity average fluorescence lifetime of 8 ns. The new TWCDs demonstrated good antioxidant properties by the ABTS radical cation method (75% inhibition at TWCDs’ concentration of 5 mg/mL), which proved to be related to the dwell time used in the CDs synthesis. Moreover, the synthesized TWCDs suppressed the growth of Escherichia coli and Staphylococcus aureus at concentrations higher than 2000 μg/mL, encouraging future antibacterial applications.
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Open AccessArticle
Subcritical Water Processing of Grape Pomace (Vitis vinifera L.): Kinetic Evaluation of Sugar Production and By-Product Formation
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Luiz Eduardo Nochi Castro, William Gustavo Sganzerla, Larissa Resende Matheus, Vanessa Cosme Ferreira, Mauricio Ariel Rostagno and Tania Forster-Carneiro
Biomass 2025, 5(2), 34; https://doi.org/10.3390/biomass5020034 - 3 Jun 2025
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This study investigates the competitive dynamics of reducing sugar production and degradation during the subcritical water processing (SWP) of lyophilized grape pomace (LGP), with the goal of optimizing sugar yield. Under the SWP conditions tested (150 °C, 150 bar, pH 7, S/F of
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This study investigates the competitive dynamics of reducing sugar production and degradation during the subcritical water processing (SWP) of lyophilized grape pomace (LGP), with the goal of optimizing sugar yield. Under the SWP conditions tested (150 °C, 150 bar, pH 7, S/F of 30 g water g−1 LGP, and a flow rate of 5 mL min−1), we achieved a reducing sugar yield of 296.0 mg sugars g−1 LGP, effectively balancing sugar production and degradation. Sugar yield decreased as the temperature increased from 150 °C to 210 °C, due to the degradation of monosaccharides into by-products like furfural and 5-HMF. A first-order reaction model was developed to better understand the kinetic competition between sugar formation and degradation at varying temperatures. The highest sugar yield occurred at 150 °C, where sugar production was maximized, and degradation was minimized. These findings offer valuable insights for subcritical water processing in the valorization of LGP into fermentable sugars while minimizing the formation of undesirable by-products.
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Open AccessArticle
Evaluation of Heavy Metal Adsorption Efficiency of Biochars Derived from Agricultural Waste
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Velyana Georgieva, Lenia Gonsalvesh, Sonia Mileva, Mariyana Hamanova and Hyusein Yemendzhiev
Biomass 2025, 5(2), 33; https://doi.org/10.3390/biomass5020033 - 3 Jun 2025
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This study investigates the potential of biochars derived from agricultural waste biomass for the removal of heavy metal ions from aqueous solutions. Biochars were produced via slow pyrolysis at 793 K using almond shells (AS), walnut shells (WS), pistachio shells (PS), and rice
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This study investigates the potential of biochars derived from agricultural waste biomass for the removal of heavy metal ions from aqueous solutions. Biochars were produced via slow pyrolysis at 793 K using almond shells (AS), walnut shells (WS), pistachio shells (PS), and rice husks (RH) as feedstocks. The physicochemical properties and adsorption performance of the resulting materials were evaluated with respect to Cd(II), Mn(II), Co(II), Ni(II), Zn(II), total Iron (Fetot), total Arsenic (Astot), and total Chromium (Crtot) in model solutions. Surface morphology, porosity, and surface chemistry of the biochars were characterized by scanning electron microscopy (SEM), nitrogen adsorption at 77 K (for specific surface area and pore structure), Fourier-transform infrared spectroscopy (FTIR), and determination of the point of zero charge (pHpzc). Based on their textural properties, biochars derived from WS, PS, and AS were classified as predominantly microporous, while RH-derived biochar exhibited mesoporous characteristics. The highest Brunauer–Emmett–Teller (SBET) surface area was recorded for PS biochar, while RH biochar showed the lowest. The pistachio shell biochar exhibited the highest specific surface area (440 m2/g), while the rice husk biochar was predominantly mesoporous. Batch adsorption experiments were conducted at 25 °C, with an adsorbent dose of 3 g/L and a contact time of 24 h. The experiments in multicomponent systems revealed removal efficiencies exceeding 87% for all tested metals, with maximum values reaching 99.9% for Cd(II) and 97.5% for Fetot. The study highlights strong correlations between physicochemical properties and sorption performance, demonstrating the suitability of these biochars as low-cost sorbents for complex water treatment applications.
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Open AccessReview
Advancements in Sustainable Biochar Production from Waste: Pathways for Renewable Energy Generation and Environmental Remediation
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Sara Mrhari Derdag and Naaila Ouazzani
Biomass 2025, 5(2), 32; https://doi.org/10.3390/biomass5020032 - 26 May 2025
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In response to significant environmental challenges, biochar has garnered attention for its applications across diverse fields. Characterized by high carbon content resulting from the thermal degradation of biomass, biochar offers a sustainable strategy for waste valorization and environmental remediation. This paper offers a
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In response to significant environmental challenges, biochar has garnered attention for its applications across diverse fields. Characterized by high carbon content resulting from the thermal degradation of biomass, biochar offers a sustainable strategy for waste valorization and environmental remediation. This paper offers a comprehensive overview of biochar production from residual biomass, emphasizing feedstock selection, conversion pathways, material properties, and application potential. Key production techniques, including pyrolysis, gasification, and hydrothermal carbonization, are critically evaluated based on operational conditions, energy efficiency, product yield, and environmental implications. The functional performance of biochar is further discussed in the context of soil enhancement, wastewater treatment, renewable energy generation, and catalytic processes, such as biohydrogen production. By transforming waste into value-added products, biochar technology supports circular economy principles and promotes resource recovery. Ongoing research aimed at optimizing production processes and understanding application-specific mechanisms is crucial to fully realizing the environmental potential of biochar.
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Open AccessArticle
Waste Nutshell Particulate Biocomposites with Geopolymer Matrix
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Filip Brleković, Katarina Mužina, Tatjana Haramina and Stanislav Kurajica
Biomass 2025, 5(2), 31; https://doi.org/10.3390/biomass5020031 - 22 May 2025
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The objective of this study was to explore the potential of creating advanced insulating biocomposites using waste almond and hazelnut shells as particulate fillers, combined with a geopolymer binder, to develop sustainable materials with minimal environmental impact. Optimal conditions for the preparation of
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The objective of this study was to explore the potential of creating advanced insulating biocomposites using waste almond and hazelnut shells as particulate fillers, combined with a geopolymer binder, to develop sustainable materials with minimal environmental impact. Optimal conditions for the preparation of biocomposites were determined by measuring the compressive strengths. The aforementioned optimal conditions included a geopolymer to waste nutshell mass ratio of 2, room-temperature curing, and the use of metakaolin geopolymers activated with potassium solutions. Notably, the highest compressive strengths of 4.1 MPa for hazelnut shells biocomposite and 6.4 MPa for almond shells biocomposite were obtained with milk of lime pretreatment at 80 °C for 1 h. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and Fourier transform infrared spectroscopy (FTIR) analyses revealed better adhesion, as well as improved geopolymer gel polymerization. Furthermore, thermal conductivity and diffusivity measurements demonstrated values characteristic of insulating materials, reinforcing their potential for eco-friendly construction applications.
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Open AccessArticle
Sub-Pilot-Scale and Bench-Scale Reactor Tests and Thermodynamic Integrated Process Analysis of Production of H2 from Woody Biomass via Chemical Looping
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Ranjani Siriwardane, Jarrett Riley, Chris Atallah and Michael Bobek
Biomass 2025, 5(2), 30; https://doi.org/10.3390/biomass5020030 - 20 May 2025
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A thermodynamic integrated process assessment and experimental evaluation of the conversion of woody biomass to H2 using chemical looping approaches were explored in this work. Both a two- and three-reactor approach were evaluated for effectiveness with a CaFe2O4 oxygen
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A thermodynamic integrated process assessment and experimental evaluation of the conversion of woody biomass to H2 using chemical looping approaches were explored in this work. Both a two- and three-reactor approach were evaluated for effectiveness with a CaFe2O4 oxygen carrier (OC). Experimental test campaigns consisted of semi-batch operations where a single reactor was loaded with a batch charge of the OC and fuel. Multi-reactor approaches were experimentally simulated by switching the gas atmosphere around the batch charge of the OC. The experiments showed that woody biomass was capable of reducing CaFe2O4, enabling the production of H2 from steam oxidation. High steam conversion rates to H2 of >75% were demonstrated. Reduced CaFe2O4 catalyzed tar cracking, multi-cycle tests showed stable reactivity, and sub-pilot-scale tests showed improved reactivity and H2 yield, accompanied by improved attrition resistance after over 30 cycles. The three-reactor configuration showed the highest potential for H2 yield between the case studies, while the two-reactor configuration had the lowest auxiliary feed requirement. Both approaches showed increased yields and lower utilities than the baseline steam gasification technology.
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Open AccessArticle
Exploring Biomass Waste-Derived Biochar as a Catalyst for Levulinic Acid Conversion to γ-Valerolactone: Insights into Synthesis, Characterization, and Catalytic Performance
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Joao Carlos Alves Macedo, Maryam Shirinkar, Richard Landers and André Henrique Rosa
Biomass 2025, 5(2), 29; https://doi.org/10.3390/biomass5020029 - 17 May 2025
Cited by 1
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The transition from fossil resources to renewable raw materials derived from lignocellulosic waste is crucial for economic and environmental sustainability. Advancing toward a bio-based economy necessitates the development of innovative heterogeneous catalysts. This study explores the use of modified sugarcane bagasse biochar, embedded
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The transition from fossil resources to renewable raw materials derived from lignocellulosic waste is crucial for economic and environmental sustainability. Advancing toward a bio-based economy necessitates the development of innovative heterogeneous catalysts. This study explores the use of modified sugarcane bagasse biochar, embedded with ruthenium and iron particles, as a green catalyst for converting levulinic acid (LA) to γ-valerolactone (GVL). The efficiency of both raw and modified biochar in the LA to GVL conversion process, utilizing formic acid (FA) exclusively as the hydrogen source, was systematically assessed through characterization techniques, including XRD, TGA, XPS, and SEM/EDS. The gelification method using alginate enhanced the ruthenium and iron content on the surface of the biochar. The results demonstrate that the modified material has significant potential for efficient LA-to-GVL conversion, achieving a yield of 73.0 ± 9.2% under optimized conditions (0.5 g of BC500Fe/3%Ru at 180 °C for 3 h, with 4 mmol LA, 8 mmol FA, and 10 mL of water). Iron on the biochar surface facilitated the formation of adsorption sites for LA, supporting the notion of this novel catalyst for LA conversion in an aqueous medium in the presence of FA. This research underscores the potential of this green catalyst in advancing sustainable biomass conversion and contributes to the ongoing shift towards a bio-based economy.
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Open AccessArticle
Conversion of Sewage Sludge with Combined Pyrolysis and Gasification via the Enhanced Carbon-To-X-Output Technology
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Wolfgang Gebhard, Sebastian Zant, Johannes Neidel, Andreas Apfelbacher and Robert Daschner
Biomass 2025, 5(2), 28; https://doi.org/10.3390/biomass5020028 - 17 May 2025
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Sustainably produced hydrogen has the potential to substitute fossil fuels and significantly reduce CO2 emissions. Fraunhofer UMSICHT develops a new thermochemical conversion technology to gasify ash-rich biogenic residues and waste materials that are difficult to treat with conventional gasifiers, enabling their conversion
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Sustainably produced hydrogen has the potential to substitute fossil fuels and significantly reduce CO2 emissions. Fraunhofer UMSICHT develops a new thermochemical conversion technology to gasify ash-rich biogenic residues and waste materials that are difficult to treat with conventional gasifiers, enabling their conversion into higher-quality energy carriers such as hydrogen and syngas. Ash-rich feedstocks are difficult to convert in conventional gasification methods, as they tend to agglomerate and form slag, leading to blockages in the reactor and process disturbances. In this experimental study, hydrogen-rich syngas is produced from biogenic residual and waste materials (sewage sludge) using the Enhanced Carbon-To-X-Output (EXO) process. The EXO process is a three-stage thermochemical conversion process that consists of a combination of multi-stage gasification and a subsequent reforming step. The influence of temperature in the reforming step on the gas composition and hydrogen yield is systematically investigated. The reformer temperature of the process is gradually increased from 500 °C to 900 °C. The feedstock throughput of the pilot plant is approximately 10 kg/h. The results demonstrate that the temperature of the reforming step has a significant impact on the composition and yield of syngas as well as the hydrogen yield. By increasing the reformer temperature, the syngas yield could be enhanced. The hydrogen yield increased from 15.7 gH2/kgFeed to 35.7 gH2/kgFeed. The hydrogen content in the syngas significantly increased from 23.6 vol.% to 39 vol.%. The produced syngas can be effectively utilized for sustainable hydrogen production, as a feedstock for subsequent syntheses, or for power and heat generation.
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Open AccessArticle
Cellulose Valorization via Electrochemical Oxidation: Efficient Formate Generation for Green Energy Storage
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Shuhan Xiao and Yang Yang
Biomass 2025, 5(2), 27; https://doi.org/10.3390/biomass5020027 - 16 May 2025
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Achieving efficient electrocatalytic oxidation of cellulose-derived biomass is a pivotal strategy for advancing bioenergy utilization and achieving carbon neutrality. This study addresses the challenges of low conversion efficiency caused by cellulose’s high crystallinity and excessive energy consumption in conventional processes by proposing a
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Achieving efficient electrocatalytic oxidation of cellulose-derived biomass is a pivotal strategy for advancing bioenergy utilization and achieving carbon neutrality. This study addresses the challenges of low conversion efficiency caused by cellulose’s high crystallinity and excessive energy consumption in conventional processes by proposing a novel integrated system combining solid heteropoly acid catalytic pretreatment and electrocatalytic oxidation. By preparing the (C16TA)H2PW solid acid catalyst, we successfully achieved hydrolysis of microcrystalline cellulose under 180 °C for 60 min, attaining a glucose yield of 40.1%. Furthermore, a non-noble metal electrocatalyst system based on foam copper (CuF) was developed, with the Co3O4/CuF electrode material demonstrating a Faradaic efficiency of 85.3% for formate production at 1.66 V (vs. RHE) in 1 mol L−1 KOH electrolyte containing the pretreated cellulose mixture, accompanied by a partial current density of 153.2 mA cm−2. The mechanism study indicates that hydroxyl radical-mediated C-C bond selective cleavage dominates the formate generation. This integrated system overcomes the limitations of poor catalyst stability and low product selectivity in biomass conversion, offering a sustainable strategy for green manufacturing of high-value chemicals from cellulose.
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Open AccessReview
Valorization of Algal Biomass to Biofuel: A Review
by
Vijitha Amalapridman, Peter A. Ofori and Lord Abbey
Biomass 2025, 5(2), 26; https://doi.org/10.3390/biomass5020026 - 5 May 2025
Cited by 1
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Concerns about sustainable energy sources arise due to the non-renewable nature of petroleum. Escalating demand for fossil fuels and price inflation negatively impact the energy security and economy of a country. The generation and usage of biofuel could be suggested as a sustainable
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Concerns about sustainable energy sources arise due to the non-renewable nature of petroleum. Escalating demand for fossil fuels and price inflation negatively impact the energy security and economy of a country. The generation and usage of biofuel could be suggested as a sustainable alternative to fossil fuels. Several studies have investigated the potential of using edible crops for biofuel production. However, the usage of algae as suitable feedstock is currently being promoted due to its ability to withstand adverse environmental conditions, capacity to generate more oil per area, and potential to mitigate energy crises and climate change with no detrimental impact on the environment and food supply. Furthermore, the biorefinery approach in algae-based biofuel production controls the economy of algal cultivation. Hence, this article critically reviews different cultivation systems of algae with critical parameters including harvesting methods, intended algae-based biofuels with relevant processing techniques, other applications of valorized algal biomass, merits and demerits, and limitations and challenges in algae-based biofuel production.
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Open AccessReview
Microalgae as Functional Food Ingredients: Nutritional Benefits, Challenges, and Regulatory Considerations for Safe Consumption
by
Francisco Eleazar Martínez-Ruiz, Gabriela Andrade-Bustamante, Ramón Jaime Holguín-Peña, Prabhaharan Renganathan, Lira A. Gaysina, Natalia V. Sukhanova and Edgar Omar Rueda Puente
Biomass 2025, 5(2), 25; https://doi.org/10.3390/biomass5020025 - 25 Apr 2025
Cited by 2
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The projected global population is expected to reach 9.7 billion by 2050, necessitating a significant increase in food production. Malnutrition remains a global health challenge that contributes to over 3.5 million deaths annually and accounts for 45% of all child mortalities. Microalgae, including
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The projected global population is expected to reach 9.7 billion by 2050, necessitating a significant increase in food production. Malnutrition remains a global health challenge that contributes to over 3.5 million deaths annually and accounts for 45% of all child mortalities. Microalgae, including cyanobacteria, are a promising solution because of their rich composition of bioactive compounds such as polyunsaturated fatty acids, carotenoids, proteins, vitamins, and minerals. These biomolecules provide various health benefits, including antioxidant, antidiabetic, anticancer, anti-inflammatory, and cardioprotective properties, making microalgal biomass a valuable ingredient in functional food formulations. However, the large-scale adoption of microalgae for food production faces several challenges, including species-specific variations in biochemical composition, inconsistencies in biomass yield, structural alterations during extraction and purification, sensory issues, and bioprocessing inefficiencies. Furthermore, regulatory challenges and concerns regarding bioavailability and safety continue to limit their widespread acceptance. Despite these limitations, microalgal bioactives have significant potential for the development of next-generation nutraceuticals and functional foods. This review examines the bioactive compounds found in microalgae, detailing their biological activities and functional applications in the food industry. Additionally, it explores the key challenges preventing their integration into food products and proposes strategies to overcome these challenges, ultimately facilitating the commercialization of microalgae as a sustainable and health-promoting food source.
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Open AccessArticle
Cassia grandis L.f. Pods as a Source of High-Value-Added Biomolecules: Optimization of Extraction Conditions and Extract Rheology
by
Filipe M. M. Cordeiro, Salomé G. Bedoya, Daniel A. P. Santos, Rebeca S. Santos, Thomas V. M. Bacelar, Filipe S. Buarque, George Simonelli, Ana C. M. Silva and Álvaro S. Lima
Biomass 2025, 5(2), 24; https://doi.org/10.3390/biomass5020024 - 25 Apr 2025
Abstract
High-value-added biomolecules such as phenolic compounds and flavonoids from secondary metabolism and macromolecules such as sugars are the main constituents of several plants. Thus, this work aims to optimize the extraction of these biomolecules present in the pods of Cassia grandis L.f. Initially,
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High-value-added biomolecules such as phenolic compounds and flavonoids from secondary metabolism and macromolecules such as sugars are the main constituents of several plants. Thus, this work aims to optimize the extraction of these biomolecules present in the pods of Cassia grandis L.f. Initially, the effect of choline-based ionic liquids—ILs (choline chloride [Ch]Cl, dihydrogen citrate [Ch][DHC], and bitartrate [Ch][BIT]) as extracting agents for phenolic compounds and flavonoids was evaluated based on their efficiency and selectivity. Then, a 23 full factorial design with six central points was performed using the IL concentration, the solid–liquid ratio, and the temperature as independent variables. The extract obtained in the best condition was subjected to pervaporation, after which the concentrates and the crude extract were used to determine the physical properties (density, viscosity, and refractive index). The hydrophobic–hydrophilic balance of the extracting agent and the biomolecules are the extraction process’s driving force. The best extraction condition was formed by [Ch][DHC] at 15 wt%, with a solid–liquid ratio of 1:15, at 45 °C for 30 min, resulting in 153.71 ± 5.81 mg·g−1 of reducing sugars; 483.51 ± 13.10 mg·g−1 of total sugars; 11.79 ± 0.54 mg·g−1 of flavonoids; and 38.10 ± 2.90 mg·g−1 of total phenolic compounds. All the physical properties of the biomolecules are temperature-dependent; for density and refractive index, a linear correlation is observed, while for viscosity, the correlation is exponential. Increasing the temperature decreases all properties, and the extract concentration for 8× presents the highest values of density (1.283 g·cm−3), viscosity (9224 mPa·s), and refractive index (1.467).
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(This article belongs to the Topic Recovery and Use of Bioactive Materials and Biomass)
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Open AccessArticle
Modified Hydrothermal Pretreatment Conditions Enhance Alcohol Solubility of Lignin from Wheat Straw Biorefining
by
Tor Ivan Simonsen, Demi Tristan Djajadi and Sune Tjalfe Thomsen
Biomass 2025, 5(2), 23; https://doi.org/10.3390/biomass5020023 - 24 Apr 2025
Abstract
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Lignin-rich residues from lignocellulosic biorefineries remain underutilized, limiting their economic viability. This study demonstrates how modifying hydrothermal pretreatments with temperatures and additives enhances the lignin-rich residue’s solubility in alcohol, a key step toward its valorization in biofuel and material applications. Effective carbohydrate removal
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Lignin-rich residues from lignocellulosic biorefineries remain underutilized, limiting their economic viability. This study demonstrates how modifying hydrothermal pretreatments with temperatures and additives enhances the lignin-rich residue’s solubility in alcohol, a key step toward its valorization in biofuel and material applications. Effective carbohydrate removal greatly enhanced the residue’s alcohol solubility, supporting both saccharification and lignin utilization. Notably, a 5% hydrogen peroxide treatment doubled the residue’s alcohol solubility, reaching ~40%, while maintaining similar saccharification yields. Low concentrations of surfactants and oxidizers enhanced the alcohol solubility independently of the saccharification yield, while alkali improved both. These findings highlight that minor pretreatment adjustments, such as low-concentration additives, can optimize lignin’s utilization in biorefineries, while maintaining a high carbohydrate conversion
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Open AccessArticle
Extraction, Isolation, and TEMPO-NaBr-NaClO Oxidation Modification of Cellulose from Coffee Grounds
by
Mourad Ouhammou, Abdellah Mourak, Aziz Ait-Karra, Jaouad Abderrahim, Najat Elhadiri and Mostafa Mahrouz
Biomass 2025, 5(2), 22; https://doi.org/10.3390/biomass5020022 - 3 Apr 2025
Abstract
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This study investigates the extraction, isolation, and chemical modification of cellulose from coffee ground residues using TEMPO-NaBr-NaClO oxidation. These residues represent a promising renewable source of cellulose, which is obtained after the removal of impurities such as lignin (24%), hemicellulose (42%), and other
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This study investigates the extraction, isolation, and chemical modification of cellulose from coffee ground residues using TEMPO-NaBr-NaClO oxidation. These residues represent a promising renewable source of cellulose, which is obtained after the removal of impurities such as lignin (24%), hemicellulose (42%), and other compounds. The TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-catalyzed oxidation selectively converts primary hydroxyl groups into carboxylate groups (-COOH) under mild conditions in aqueous media, achieving an oxidation yield of up to 67%. Structural and morphological analyses, including scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD), confirm the successful chemical modification of the cellulose. The results indicate a reduction in crystallinity index from native cellulose (80%) to oxidized cellulose (65%), reflecting partial disruption of the microfibril structure and the introduction of new chemical functionalities. FTIR analysis reveals the appearance of characteristic carboxylate bands, confirming the conversion of hydroxyl groups into carboxyl groups. Energy-dispersive X-ray (EDX) analysis further highlights a significant increase in oxygen content, indicating the efficiency of the oxidation process. The TEMPO-oxidized cellulose is water-soluble, enabling the production of valuable polyelectrolytes and intermediates. These chemical modifications improve the cellulose’s reactivity, broadening its potential applications in various fields, including biocomposites, sustainable packaging materials, and functional films. This work demonstrates the feasibility of utilizing coffee ground residues as a renewable, eco-friendly source of modified cellulose for high-value applications.
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