Biomass

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 g_H2/kg_Feed to 35.7 g_H2/kg_Feed. 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. Full article

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. Full article

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. Full article

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. Full article

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). Full article

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 Full article

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. Full article

This study assesses Queensland’s sugar industry potential for sustainable aviation fuel (SAF) production via biomass-to-liquids (BtL) processes. Using surplus sugarcane bagasse, preliminary estimates suggest that individual mills could support 60–130 MW_th gasifiers, while clustered approaches enable larger capacities. Annual BtL syncrude production could reach 440 mL, increasing to ~1000 mL with additional feedstocks. These findings highlight both the industrial-scale viability of SAF production and the logistical and engineering challenges that must be addressed to align with Australia’s renewable energy and fuel security goals. Full article

Stochastic models can be used for predicting the availability of residual woody forest biomass, considering the variability and uncertainty associated with climatic, operational, and economic factors. These models, such as ARIMA, GARCH, state transition models, and Monte Carlo simulations, are widely used to capture seasonal patterns, dynamic variations, and complex uncertainties. Their application supports critical decisions in forest and energy operations planning. The implementation of the models was carried out in Python, using specialized packages such as Statsmodels for ARIMA, Arch for GARCH, and PyMC3 for state transition models. Probabilistic calculations were performed with Numpy and Scipy, while Matplotlib and Seaborn were used for data visualization. Hypothetical data simulating real-world scenarios were analyzed, divided into training and testing sets, with cross-validation and metrics such as RMSE, MAPE, and R2. ARIMA demonstrated high accuracy in capturing seasonality, while GARCH effectively modeled volatility. Monte Carlo simulations provided the most reliable forecasts, capturing uncertainties across multiple scenarios. The models excelled in predicting periods of high biomass availability with robust projections. The results confirm the efficacy of stochastic models in predicting residual biomass, with a positive impact on sustainable planning. However, challenges such as data dependency and computational resources still need to be addressed, pointing to directions for future research and methodological improvements. Full article

Sustainable agricultural practices are essential to address global food security challenges while minimizing environmental impacts. This study aimed to evaluate integrated farming systems with varying levels of integration (from lower to higher)—maize monoculture + livestock (MM), maize + cover crop + mixed prairie + livestock (MCP), and maize + red clover + mixed prairie + livestock (MRP)—to assess their contributions to circularity and sustainability. The research examined biomass and protein production, nutrient cycling, energy use, food needs covered, and workload over two cropping cycles. The findings revealed that highly integrated systems (MRP and MCP) significantly enhance biomass production, energy efficiency, and nutrient recycling compared to the MM system (p < 0.05). MRP produced 4 times more biomass than MM (9.4 t ha⁻¹), while MCP achieved a 0.99 Nitrogen Recycling Index compared with 0.38 in MM, underscoring the benefits of grazing and increasing agrobiodiversity. Integrated systems also improved soil health (+17.4% organic matter in MRP and MCP, +91.5% nitrogen in MCP), reduced dependency on synthetic inputs, and boosted protein production (animal-derived protein in MRP and MCP = 395.4 kg, MM = 73.7 kg), thus meeting food needs for large populations. However, they required increased labor and technical expertise, presenting adoption barriers for smallholders. The synergy between agroecological practices and circularity offers a pathway to sustainable intensification, fostering economic, environmental, and social resilience. In this way, the results highlighted the potential of integrated farming systems to transform agricultural systems. Full article

The aim of this study is the quantitative and qualitative characterization of food waste from the restaurant sector in Riobamba, Ecuador as part of circular economy efforts. A weekly analysis of waste generation data collected from 13 participating restaurants showed that the average daily food waste generated was 18.48 kg/restaurant/day. The highest percentage (55%) was produced by organic waste, which was primarily composed of waste from vegetables. Plastics represented most of the recyclable waste (21%), and 24% of the waste was disposable. With a low dry matter content of 24.33 ± 5.12% and an average moisture level of 75.68 ± 5.12%, the high organic content indicates its potential for value-adding through biological recycling processes like anaerobic digestion and composting. Fruit and vegetable waste had high moisture levels (80.3 ± 2.54% and 81.2 ± 2.75%, respectively), which made them perfect for composting and biogas production. However, the moisture and dry matter contents differed greatly amongst the waste categories. The increased dry matter concentration of animal protein waste (54.5 ± 4.30%) indicated that it may be converted into products with added value, such as animal meal and oils. Plant protein waste needs to be processed quickly to avoid spoiling because of its extraordinarily high moisture content (95.7 ± 3.20%) and low dry matter (4.3 ± 3.20%). The findings underscore the necessity for focused measures, such as composting, anaerobic digestion, and enhanced recycling, to optimize resource recovery and mitigate environmental consequences. Full article

Pineapple (Ananas comosus) is one of the most economically important fruit cultivars in South Africa. The fruit is locally consumed, processed into various industrial products or exported to foreign markets. Approximately 115,106 metric tons of pineapple fruit are harvested in South Africa. The pineapple value chain generates significant amounts of waste, in the form of pomace, peel, crown, stem, core and base. If not properly treated, pineapple waste (PAW) could have a profound detrimental impact on the environment. This calls for advanced technological platforms to transform PAW into useful bio-based products. A biorefinery is a potent strategy to convert PAW into multiple food and non-food products while effectively disposing of the waste. The objective of this review is to explore possible pathways for the valorization of PAW into energy and material products in a biorefinery. The paper looks at 10 products including biogas, biohythane, bioethanol, biobutanol, biohydrogen, pyrolytic products, single-cell proteins, animal feed, vermicompost and bioactive compounds. Several platforms (i.e., biochemical, chemical, physical and thermochemical) are available to convert PAW into valuable goods. Amongst them, the biochemical route appears to be the most favorable option for the valorization of PAW. Anaerobic digestion and fermentation are well-established biochemical technologies for PAW valorization. These methods are simple, low-cost, eco-friendly and sustainable. The focal point of emerging research is the enhanced efficacy of biorefinery platforms. The commercialization of PAW biorefining is a potential gamechanger that could revitalize the entire South African economy. Full article

India’s rapidly growing automobile industry has intensified the need for sustainable fuel alternatives to reduce dependency on imported fossil fuels and mitigate greenhouse gas (GHG) emissions. This study examines the potential of second-generation biorefineries as a comprehensive solution for efficient biomass valorization in India. With a projected bioethanol demand of 10,160 million liters by 2025 for India’s 20% ethanol blending target, there is an urgent need to develop sustainable production pathways. The biorefinery approach enables simultaneous production of multiple valuable products, including bioethanol, biochemicals, and bioproducts, from the same feedstock, thereby enhancing economic viability through additional revenue streams while minimizing waste. This paper systematically analyzes available biomass resources across India, evaluates integrated conversion technologies (biochemical, thermochemical, and synergistic approaches), and examines current policy frameworks supporting biorefinery implementation. Our findings reveal that second-generation biorefineries can significantly contribute to reducing GHG emissions by up to 2.7% of gross domestic product (GDP) by 2030 while creating rural employment opportunities and strengthening energy security. However, challenges in supply chain logistics, technological optimization, and policy harmonization continue to hinder large-scale commercialization. The paper concludes by proposing strategic interventions to overcome these barriers and accelerate the transition toward a sustainable circular bioeconomy in India. Full article

This study explores the extraction and utilization of tannins from Acacia sp. bark residues for water treatment applications. As a by-product of forest management, Acacia sp. bark is valorized through tannin-based coagulant production, contributing to the circular (bio)economy. A systematic review with bibliometric analysis was first conducted to assess the technical–scientific landscape, identifying methodologies and technologies applied to extract and produce natural tannin-based coagulants from Acacia sp. bark residues for water treatment. From the portfolio of analyzed publications, and which followed the thematic axis addressed and the inclusion criteria, only a single study focuses on performing a life cycle assessment (LCA). Due to the relevance of the topic and the clear lack of existing literature, an environmental assessment of the extraction and production of condensed tannins was performed using the LCA methodology from a gate-to-gate perspective. Among the six process stages, spray drying and adsorption (purification) were the primary sources of environmental impact due to their high energy consumption and makeup ethanol use, respectively. The most effective strategy to enhance environmental performance would be reducing water consumption in extraction, thereby lowering energy demand in spray drying. Since both extraction and spray drying require significant energy, decreasing water use and allowing higher moisture content in the condensed tannin extract would mitigate energy consumption. The LCA study thus proved essential in guiding process development toward a reduced environmental footprint. Full article

The energy crisis has highlighted the need for a significant change in Kosovo’s lignite-based electrical energy system, particularly greater investments in renewable energy sources. These sources would provide greater price stability, centralized accessibility, and relatively affordable investment costs. This research tries to analyze the basic attitudes behind the behavior of the students from the agricultural faculty in Kosovo in order to acquire a better understanding of their preferences for renewable energy source purchases, using the Best–Worst Scaling (BWS) method and cluster analysis. Students’ perspectives on renewable energy show strong environmental and price conscientiousness in BWS methods (first and second rank), while the rate of eco-skeptic students reaches only 23% in the cluster analysis, which is a very promising sign of the younger generation’s growing dedication to sustainability. Students, as future decision-makers, can play a critical role in making the transition to a more sustainable and resilient agricultural system. Green transition in Kosovo can be reached by combining the importance of dissemination and marketing tools with the pressing demand for renewable energy solutions, which might be interesting not only for Kosovo, but (considering the expectable enlargement) also for the EU. Full article

China has abundant biomass and renewable energy resources suitable for producing green methanol via biomass thermochemical conversion. Given China’s increasing demand for sustainable fuel alternatives and the urgency to reduce carbon emissions, optimizing biomass utilization through gasification is critical. Research has highlighted the potential of integrating biomass gasification with water electrolysis to enhance efficiency in green methanol production, leveraging China’s vast biomass reserves to establish a cleaner energy pathway. Four main biomass gasification technologies—fixed-bed, fluidized-bed, pressurized fluidized-bed, and entrained-flow—have been investigated. Fixed-bed and bubbling fluidized-bed gasification face low gas yield and scaling issues; whereas, circulating fluidized-bed gasification (CFB) offers better gas yield, carbon efficiency, and scalability, though it exhibits high tar and methane in syngas. Pressurized fluidized-bed gasification improves gasification intensity, reaction rate, and equipment footprint, yet stable feedstock delivery under pressure remains challenging. Entrained-flow gasification achieves high carbon conversion and low tar but requires finely crushed biomass, restricted by biomass’ low combustion temperature and fibrous nature. Current industrially promising routes include oxygen-enriched and steam-based CFB gasification with tar cracking, which reduces tar but requires significant energy and investment; oxygen-enriched combustion to produce CO₂ for methanol synthesis, though oxygen in flue gas can poison catalysts; and a new high oxygen equivalence ratio CFB gasification technology proposed here, which lowers tar formation and effectively removes oxygen from syngas, thereby enabling efficient green methanol production. Overcoming feedstock challenges, optimizing operating conditions, and controlling tar and catalyst poisoning remain key hurdles for large-scale commercialization. Full article

Cotton biomass residues consist of an important portion of the agricultural byproducts. In this work, we systematically analyzed and compared the morphology and thermal properties of nine cotton biomass byproducts. The unique tubular and/or porous morphology of some samples (e.g., main stems, branch stems, and petioles) implied their structural advantage in the development of electric supercapacitors and pollutant absorbents. The higher heating values of the nine samples ranged between 17 and 20 MJ kg⁻¹, higher than some of the other common agricultural byproducts (e.g., rice husk and sugarcane bagasse). The moisture content showed a positive correlation (p > 0.05) to the dehydration temperature of the differential scanning calorimetric plots. The residual char after thermogravimetric analysis could be separated into a high-yield cluster (34.4–26.6%) of leaf blades, bracts/peduncles, burrs, defatted meal, and petioles, and a low-yield cluster (20.5–13.6%) of main stems, branch stems, cotton gin waste, and cottonseed hull. These observations and data are useful for a better understanding of the fundamental chemistry of cotton biomass byproducts. Growing knowledge is useful for improving their recycling strategies and may shed light on the exploration of new value-added products or applications from these cotton biomass byproducts for a circular economy with sustainable agriculture. Full article

Microalgae have emerged as a valuable source of essential nutrients and bioactive compounds, such as proteins, polyphenols, and polysaccharides, which are critical for overall health. Recent research has demonstrated the therapeutic potential of microalgae in addressing a variety of health conditions, including inflammation, oxidative stress, Type 2 diabetes mellitus (T2DM), and neurological disorders. The aim of this paper is to investigate the chemical composition, nutritional value, and biological properties of microalgae. Relevant information was gathered through a comprehensive search of scientific databases, including PubMed, Science Direct, Google Scholar, and the Cochrane Library. Key microalgal strains such as Spirulina platensis, Chlorella vulgaris, Haematococcus pluvialis, and Dunaliella salina have shown notable health-promoting properties. For instance, Spirulina platensis is rich in proteins, vitamins, and polyunsaturated fatty acids, while Chlorella vulgaris offers significant levels of chlorophyll and carotenoids. Haematococcus pluvialis is recognized for its high astaxanthin content and Dunaliella salina for its beta-carotene content. These microalgae strains have demonstrated beneficial effects in managing type 2 diabetes mellitus, alleviating oxidative stress, and offering neuroprotective potential. This paper provides an overview of microalgae’s nutritional composition, their medicinal properties, and their promising role in treating chronic diseases, with a particular focus on their applications in antidiabetic and neuroprotective therapies. Full article

Decentralized energy generation by renewable fuels is an alternative to energy dependency and reduction in greenhouse gas emissions, with biogas emerging as a promising option. Brazil, as the second largest ethanol producer, generates several by-products in the production of this biofuel that could be used for biogas production. In this study, the potential for biogas production and electricity generation from biogas was evaluated. Furthermore, an economic analysis was conducted with calculations of discounted net present value (NPV), internal rate of return (IRR), return on investment (ROI), Levelized Cost of Electricity (LCOE), and sensitivity analysis related to the implementation of vinasse anaerobic digestion, and vinasse and filter cake co-digestion in seven sugarcane mills in Paraná state, Brazil. The results demonstrated that co-digestion and higher sugarcane milling capacities benefit biogas generation and economic aspects. Additionally, implementing anaerobic digestion for electricity production was viable in all scenarios, indicating that biogas from the sugarcane sector could be a viable alternative for decentralized energy generation. Full article