Biomass, Volume 6, Issue 1 (February 2026) – 17 articles

Renewable energy systems are increasingly critical for achieving decarbonization and long-term energy security, particularly in rural regions with abundant local resources. While solar and wind technologies have become cost-competitive, their intermittency limits reliability when deployed independently. Biomass, by contrast, offers dispatchable renewable power but faces economic challenges related to feedstock logistics. This study evaluates a biomass-led hybrid renewable energy system (HRES) for Grenada County, Mississippi, integrating biomass, solar photovoltaic (PV), and wind resources to enhance system reliability and reduce environmental impacts. System performance and optimization were assessed using the System Advisor Model (SAM) and the Hybrid Optimization of Multiple Energy Resources (HOMER). The proposed configuration comprises approximately 80% biomass, 10% solar PV, and the remaining share from wind, producing a total annual electricity output of about 423 GWh, sufficient to meet regional demand. The subsystem-level levelized cost of energy (LCOE) was estimated at 12.10 cents/kWh for biomass, 4.07 cents/kWh for solar PV, and 8.62 cents/kWh for wind, with the overall hybrid cost influenced primarily by biomass feedstock transportation and storage. Environmental impact assessment based on U.S. EPA eGRID and IPCC factors indicates that the hybrid system achieves a weighted emission intensity of approximately 28.4 kg CO₂-eq/MWh, representing a reduction of over 94% compared to the regional grid. When scaled to annual generation, this corresponds to roughly 197,000 metric tons of avoided CO₂-equivalent emissions per year, alongside 80–95% reductions in acidification and eutrophication impacts. The results demonstrate that biomass-anchored hybrid systems can provide a reliable, low-carbon pathway for rural energy development, with further cost reductions achievable through targeted policy incentives and financing support. Full article

This study investigates the potential of tomato waste (TW) and hot pepper waste (HPW) biomass from local food industries in Algeria as sustainable feedstocks for fluidized-bed air gasification. Conversion efficiency, syngas composition and energy content were evaluated under different operating conditions, including gasification temperature (750 and 850 °C) and bed material (silica sand, olivine, and a ZSM-5 zeolite catalyst/silica sand mixture). The results demonstrate that gasification of these biomasses in a bubbling fluidized-bed reactor is an effective waste-valorization route, producing a syngas rich in hydrogen and methane, suitable for power generation and biofuel applications. Under all operating conditions, hot pepper waste generated a syngas with higher energy content than tomato pomace. Full article

In this study, barley biomass from the brewing industry was used to obtain fraction-rich arabinoxylans, polysaccharides that, due to their chemical and structural properties, can form films. The effect of adding three plasticizers at a concentration of 20% w/w on the mechanical, optical, and barrier properties of the thermoplasticized films was evaluated. Tensile strength (TS) and percent elongation (%E) tests were performed to determine the mechanical properties, water vapor transmission rate (WVTR) and water vapor permeability (WVP) were evaluated by gravimetric methods, the ΔE and color index (CI) were calculated with the chromatic coordinates of the CIE-L*a*b system, and structural morphology was determined by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR-ATR). The results show that plasticizers decrease the TS values and increase the %E, obtaining more flexible films compared to films made without plasticizers. The structural characteristics of plasticizers directly influence the CI of films. The values corresponding to %E and PVA were higher in the arabinoxylan films thermoplasticized with glycerol. Films’ stability was evaluated using electrochemical impedance spectroscopy. The results show that there are significant differences when the films are coated with polylactic acid. Full article

This paper explores the complex interrelationships between biomass composition, thermochemical conversion pathways, carbon yield and other characteristics in order to expand the knowledge for biomass conversion processes and adapt them to specific requirements. A comprehensive characterization, chemical and thermal analysis of peach stone biomass, was performed. Thermogravimetric analysis, elemental analysis and low-temperature nitrogen sorption were also carried out in order to establish the composition and textural characteristics of the precursor material and obtained product. Carbon adsorbents were obtained from the studied biomass precursor under different conditions via one-step hydro-pyrolysis process by using steam activation at 800 °C. After research was conducted, it was established that cellulose is the main component, which influences the quantity and quality of the obtained adsorbent. The high content of hemicellulose reveals peach stones as a good candidate, especially for hydrothermal carbonization. High cellulose content (40%) in the biomass precursor is a prerequisite for the formation of porous texture in carbon adsorbent during hydro-pyrolysis. It was also shown that the carbon yield (26.70%) can be predicted and is highly dependent on the precursor composition. These results highlight the potential of peach stones as a valuable precursor for the production of sustainable, high-performance carbon adsorbents for environmental remediation. Full article

This manuscript provides a comprehensive review of the enzymatic hydrolysis of lignocellulosic biomass, emphasizing how chemical composition, structural features, inhibitory compounds, and process configurations collectively influence the conversion of structural polysaccharides into fermentable sugars. Variability among herbaceous, woody, and residual biomasses results in differences in cellulose, hemicellulose, lignin content, and crystallinity, which strongly affect enzyme accessibility. The review discusses key inhibitory mechanisms, including nonproductive cellulase adsorption onto lignin, interference from phenolic derivatives and pretreatment by-products, and inhibition caused by accumulating mono- and oligosaccharides. Process configurations such as SHF, SSF, PSSF, and consolidated bioprocessing are compared, with SSF often achieving superior performance by mitigating end-product inhibition. The manuscript also highlights the growing relevance of computational modeling and simulation tools, which support kinetic prediction, the evaluation of transport limitations, and the optimization of operating conditions in high-solids systems. Additionally, recent advances in artificial intelligence are presented as powerful approaches for modeling nonlinear hydrolysis behavior, estimating kinetic parameters, identifying rate-limiting steps, and improving predictive accuracy in complex bioprocesses. Overall, the integration of experimental insights with advanced modeling, simulation, and AI-based strategies is essential for overcoming current limitations and enhancing the technical feasibility and industrial competitiveness of lignocellulosic bioconversion. Full article

Kinetic models are important tools for guiding the design and optimization of lipase-catalyzed processes. These processes follow the Ping Pong bi bi mechanism, for which mechanistic kinetic equations can be derived. However, when there are several competing reactions, fully mechanistic models contain a large number of parameters, making it difficult to obtain reliable estimates, so simplified models are necessary. We present a two-step approach to developing semi-mechanistic models of such processes. The first step involves the estimation of the selectivities of the enzyme, using profiles for the reaction species plotted against the degree of reaction, while the second step involves empirical fitting to the same data, but plotted as a function of time. We demonstrate this two-step approach through four case studies based on the literature data for the lipase-catalyzed esterification of fatty acids with trimethylolpropane to produce biolubricants. The semi-mechanistic models were able to describe the data well. Our approach has the advantage of allowing selectivities to be estimated without confounding effects from phenomena such as enzyme denaturation and inhibition. It therefore provides a promising framework for developing models of enzyme-catalyzed processes that obey Ping Pong bi bi kinetics. Full article

Kappaphycus alvarezii is an important source of carrageenan, a polysaccharide widely utilized for its gelling and stabilizing properties. However, understanding advancements in its application is crucial for broadening its biotechnological uses and promoting sustainable practices. This study aimed to conduct a systematic review of the applications of carrageenan from K. alvarezii, following PRISMA guidelines. A search was conducted in the CAPES Journals Portal and Scopus databases from 2010 to 2025, using the descriptors “Kappaphycus alvarezii” and “carrageenan.” Out of 491 analyzed articles, 38 met the inclusion criteria, categorized into health/medicine (n = 11), human food (n = 10), general industry (n = 8), animal nutrition (n = 6), and agriculture (n = 3). The findings reveal various applications, including scaffolds, antimicrobial agents, encapsulants, and wound dressings in health/medicine; edible films and food additives in human food; biomaterials and bioproducts, as well as applications in biorefinery in general industry; applications in aquaculture and livestock in animal nutrition; and as a defense inducer or biostimulant in agriculture. Despite a limited number of articles specifically addressing the direct applications of carrageenan from K. alvarezii, its uses are extensive across various industries. Full article

This study analyzes the valorization of oil palm biomass residues within the framework of industrial symbiosis (IS), emphasizing their role in circular economy strategies and sustainable industrial development. Through a systematic literature review and snowball sampling, 156 articles indexed in Scopus and Web of Science were examined, classifying evidence by country, type of residue, derived products, economic sector (ISIC Rev. 4), and technological approach. The results show a strong geographical concentration of IS experiences in Asia, particularly Malaysia, Indonesia, and Thailand, where residues such as empty fruit bunches (EFB), palm kernel shells (PKS), oil palm mesocarp fibers, palm oil mill effluent (POME), and oil palm trunks (OPT) are integrated into processes for bioenergy, biochemicals, composite materials, construction products, biochar, and bioplastics. In contrast, applications in Latin America and Africa remain incipient, with high potential but limited industrial implementation due to infrastructural and regulatory gaps. Technological trends point toward thermo-chemical and biological conversion routes (pyrolysis, gasification, hydrothermal carbonization, anaerobic digestion), development of advanced materials and catalysts, and the emergence of integrated biorefinery models supported by computational optimization tools. The analysis highlights that palm biomass residues, far from being an environmental liability, constitute strategic resources for low-carbon value chains. However, scaling IS initiatives requires clear public policies, economic incentives, and stronger coordination between industry, government, and academia. The study provides a structured overview of current knowledge, identifies research gaps, and outlines future directions for leveraging oil palm residues as a key input for sustainable IS. Full article

The massive influx of pelagic Sargassum in the Caribbean poses a serious environmental, social, and economic problem, as the stranded biomass is often treated as waste and deposited in landfills. This literature review synthesizes recent research highlighting its potential for valorization in various industries, turning this challenge into an opportunity. Sargassum has low levels of protein and lipids. Still, it is particularly rich in carbohydrates, such as alginates, fucoidans, mannitol, and cellulose, as well as secondary metabolites, including phenolic compounds, flavonoids, pigments, and phytosterols with antioxidant and bioactive properties. These biochemical characteristics allow for its application in renewable energy (bioethanol, biogas, biodiesel, and combustion), agriculture (fertilizers and biostimulants), construction (composite materials, cement additives, and insulation), bioremediation (adsorption of heavy metals and dyes), and in the health sector (antioxidants, anti-inflammatories, and pharmacological uses). A major limitation is its high bioaccumulation capacity for heavy metals, particularly arsenic, which increases environmental and health risks and limits its direct use in food and feed. Therefore, innovative pretreatment and bioprocessing are essential to mitigate these risks. The most promising approach for its utilization is a biorefinery model, which allows for the sequential extraction of multiple high-value compounds and energy products to maximize benefits, reduce costs, and sustainably transform Sargassum from a coastal pest into a valuable industrial resource. Full article

The untreated discharge of dairy industry wastewater, characterized by high organic and nutrient loads, poses a severe eutrophication threat, leading to oxygen depletion and the disruption of aquatic ecosystems, which necessitates advanced treatment strategies. Anaerobic digestion (AD) represents an effective and sustainable alternative, converting organic matter into biogas while minimizing sludge production and contributing to Circular Economy strategies. This study investigated the effects of fat concentration and operational temperature on the anaerobic digestion of dairy effluents. Three types of effluents, skimmed, semi-skimmed, and whole substrates, were evaluated under mesophilic 35 °C and thermophilic 55 °C conditions to degrade substrates with different fat content. Low-fat effluents exhibited higher COD removal, shorter lag phases, and stable activity under mesophilic conditions, while high-fat substrates delayed start-up due to accumulation of fatty acids and brief methanogen inhibition. Thermophilic digestion accelerated hydrolysis and methane production but demonstrated increased sensitivity to lipid-induced inhibition. Kinetic modeling confirmed that the modified Gompertz model accurately described mesophilic digestion with rapid microbial adaptation, while the Cone model better captured thermophilic, hydrolysis-limited kinetics. The thermophilic operation significantly enhanced methane productivity, yielding 105–191 mL CH₄ g⁻¹VS compared to 54–70 mL CH₄ g⁻¹VS under mesophilic conditions by increasing apparent hydrolysis rates and reducing lag phases. However, the mesophilic process demonstrated superior operational stability and robustness during start-up with fat-rich effluents, which otherwise suffered delayed methane formation due to lipid hydrolysis and volatile fatty acid (VFA) inhibition. Overall, the synergistic interaction between temperature and fat concentration revealed a trade-off between methane productivity and process stability, with thermophilic digestion increasing methane yields up to 191 mL CH₄ g⁻¹ VS but reducing COD removal and robustness during start-up, whereas mesophilic operation ensured more stable performance despite lower methane yields. Full article

Sewage sludge was pyrolyzed at mass rate of 500 g/h in a bench-scale rotary kiln for methane-rich syngas production. The tested process variables were the pyrolysis temperature (600, 700 and 800 °C) and the CaO addition to the process (0 and 0.2 CaO/dried sewage sludge). Product distribution (char, condensable product, and gas) as well as their chemical composition were determined. At CaO/dried sewage sludge mass ratio equal to 0, with the increasing pyrolysis temperature from 600 to 800 °C, the gas yield increased from 31.4% to 45.6 wt.%, while the char yield decreased from 41.3 to 37.5 wt.%. At CaO/dried sewage sludge mass ratio equal to 0.2, significantly different product distribution and chemical composition were detected. In fact, syngas showed a net CO₂ concentration reduction (under 10 mol %), while methane concentration increased at 600 and 700 °C up to 54 and 42 mol %, respectively. The total gas yield increased, probably because of the CaO behavior as catalyst of volatiles conversion reactions (cracking and reforming). In fact, the condensable product yield decreased up to 7 wt.% at 800 °C. At CaO/dried sewage sludge equal to 0.2 and pyrolysis temperature of 700 °C, the maximum methane yield of 150 g/kg _SS was detected. Full article

Spent coffee grounds (SCGs) are abundantly produced worldwide as a by-product of coffee brewing, and production is surging following the rise in global coffee consumption. Although the adsorption properties of raw SCGs have been investigated in previous studies, limited attention has been paid to the use of SCG-derived hydrochars as engineered adsorbents. In this work, hydrochars produced via hydrothermal carbonization (HTC) of SCGs at different temperatures were systematically assessed for their capacity to remove methylene blue (MB) dye from aqueous solution. The effect of HTC temperature and soft alkaline activation on MB adsorption were evaluated through adsorption batch tests. The soft alkaline activation increased the experimental adsorption capacity from <20 mg g⁻¹ for untreated hydrochars to approximately 100 mg g⁻¹ at 20 °C, while Langmuir isotherm analysis yielded a monolayer capacity of 147.1 mg g⁻¹ at the same temperature; experimental uptake further increased to 215.6 mg g⁻¹ at 40 °C and high dye concentrations. Kinetic, isotherm, and thermodynamic tests were performed on selected materials to describe their adsorption behavior and potential mechanisms. Microscopic, diffraction, spectroscopic, and porosimetric analyses were performed to investigate the structural differences among the tested materials. This study shows that temperature regulation and soft alkaline activation can strongly improve the adsorption capacity of the hydrochars, producing competitive low-cost adsorbents from a waste material in compliance with the principles of the circular economy. Full article

Aiming to obtain chemicals from renewable sources to mitigate global warming, the catalytic pyrolysis of tamarind pulp, obtained from juice industries, was studied. Catalysts based on HZSM-5 zeolite prepared from rice husk ash using ultrasound, microwaves, and a combination of both were used. The catalysts were characterized by elemental analysis, X-ray diffraction, specific surface area and porosity measurements, scanning electron microscopy, and acidity measurements. The specific surface areas and the micropore volumes were slightly affected by the treatments, with microwave alone or combined with ultrasound having the strongest effect. The number of acid sites increased, and the relative number of strong sites decreased with the treatments. The relative amount of Bronsted to Lewis sites was increased by ultrasound and decreased by microwave, alone or combined. These catalysts decreased oxygenated products and increased BTEX production during tamarind pulp pyrolysis. Product distribution was similar for all cases, meaning that HZSM-5 with the following characteristics is a selective catalyst for BTEX in tamarind pulp pyrolysis: specific surface area = 310–347 m²/g; micropore volume = 0.099–0.105 cm³ g⁻¹; acidity = 327 to 571 µmol NH₃ g_cat⁻¹; and ratio of Bronsted to Lewis acid sites = 0.034 to 0.044. Full article

Brazil possesses a large bioenergy resource, embedded in agro-industrial, livestock, and urban residues; this study quantifies its technical magnitude and associated energy value. An assessment was conducted by substrate, combining official statistics with literature-based yields and recovery factors. Biogas volumes were converted into biomethane using representative upgrading efficiencies, and thermal and electrical equivalents were derived from standard lower heating values and conversion efficiencies. Uncertainty bounds reflect the variability of feedstock yields and process performance. The national technical potential is estimated at roughly 80–85 billion Nm³/year of biogas, corresponding to ~43–45 billion Nm³/year of biomethane and around 168–174 TWh/year of electricity. Contributions are led by the sugar–energy complex (~one-third), followed by livestock and other agro-industrial residues (~one-third), while urban sanitation supplies ~8–10%. Potentials are concentrated in the Southeast, Center-West, and South, and current production represents only ~2–3% of the assessed potential. The findings indicate that realizing this potential requires targeted measure standardization for grid injection, support for pretreatment and co-digestion, access to credit, and alignment with instruments such as RenovaBio and “Metano Zero” to unlock significant methane-mitigation, air-quality, and decentralized energy-security benefits. Full article

The valorization of agro-industrial waste could be a strategy to improve organic waste management. The production of activated carbon (AC) is a path to use for this waste, with the aim of reducing its negative effects. AC is characterized by a high internal surface area, chemical stability, and oxygen-containing functional groups in its structure. This work is focused on the valorization of agro-industrial waste such as pineapple peel and coconut shells. These are made up of sucrose, glucose, fructose, and other essential nutrients, as well as cellulose, hemicellulose, and lignin. Activated Carbon was obtained with slow pyrolysis at 400 °C, for 4 h in a stainless-steel tubular reactor with physical activation. The obtained samples were analyzed using SEM, TGA, FTIR, and BET to verify the morphology, thermal degradation, functional groups and pores ratio of the AC, highlighting the presence of materials pore >10 µm. The TGA residual materials gave 16.3% of pineapple peel AC ashes and 0.2% of coconut AC. A C=C, C-H_X, CO, and OH stretching were observed in 400–4000 cm⁻¹. The peak intensity decreased once the biodiesel was treated with AC, because the traces of water and functional groups interacted actively, resulting a high content of bases. Activated carbon was used for dry cleaning of the obtained biodiesel from residual oil, which was effective in reducing pH and moisture levels in the biodiesel samples. Pore distribution was determined by BET, 5.6 nm for pineapple peel and 39.8243 nm for coconut shells. The obtained activated carbon offers a sustainable alternative to traditional carbon sources and contributes to the circular economy by recycling waste biomass. Full article

Waste valorization is a necessary activity for the development of the circular economy. Pyrolysis as a waste valorization pathway has been extensively studied, as it allows for obtaining different fractions with diverse and valuable applications. The joint analysis of results generated by thermogravimetry (TGA) and analytical pyrolysis (Py-GC/MS) allows for the characterization of waste materials and the assessment of their potential as sources of energy, value-added chemicals and biochar, as well as providing awareness for avoiding potential harmful emissions if the process is performed without proper control or management. In the present study, these techniques were employed on three greenhouse plant residues (broccoli, tomato, and zucchini). Analytical pyrolysis was conducted at eight temperatures ranging from 100 to 800 °C, investigating the evolution of compounds grouped by their functional groups, as well as the predominant compounds of each biomass. It was concluded that the decomposition of biomass initiates between 300–400 °C, with the highest generation of volatiles occurring around 500–600 °C, where pyrolytic compounds span a wide range of molecular weights. The production of organic acids, ketones, alcohols, and furan derivatives peaks around 500 °C, whereas alkanes, alkenes, benzene derivatives, phenols, pyrroles, pyridines, and other nitrogenous compounds increase with temperature up to 700–800 °C. The broccoli biomass exhibited a higher yield of alcohols and furan derivatives, while zucchini and tomato plants, compared to broccoli, were notable for their nitrogen-containing groups (pyridines, pyrroles, and other nitrogenous compounds). Full article

This review examines how the integration of circular bioeconomy principles with digital technologies can drive climate change mitigation, improve resource efficiency, and facilitate sustainable biorefinery development. This highlights the urgent need to transition away from fossil fuels and introduces the bio-circular economy as a regenerative model focused on biomass valorization, reuse, recycling, and biodegradability. This study compares linear, circular, and bio-circular approaches and analyzes key policy frameworks in Europe, Latin America, and Asia linked to several UN Sustainable Development Goals. A central focus is the role of digitalization, particularly artificial intelligence (AI), the Internet of Things (IoT), and blockchain. Examples include AI-based biomass yield prediction and biorefinery optimization, IoT-enabled real-time monitoring of material and energy flows, and blockchain technology for supply chain traceability and transparency. Applications in agricultural waste valorization, bioplastics, bioenergy, and nutraceutical extraction are also discussed in this review. Sustainability tools, such as automated life-cycle assessment (LCA) and Industry 4.0 integration, are outlined. Finally, future perspectives emphasize autonomous smart biorefineries, biotechnology–nanotechnology convergence, and international collaboration supported by open data platforms. Full article