Biomass, Volume 5, Issue 3 (September 2025) – 6 articles

Beer production produces significant amounts of brewers’ spent grain (BSG), a lignocellulosic by-product with important environmental and economic impacts. Despite its high moisture content and rapid microbial breakdown, BSG has a stable, nutrient-rich composition, especially high in protein, fiber, and polyphenolic compounds. While its perishability limits direct use in food systems, BSG is often repurposed as livestock feed. Recent advances in bioprocessing and extraction technologies have expanded their use across different sectors. This review explores the composition of crude BSG and evaluates innovative valorization methods, including recovering bioactive compounds with pharmaceutical and nutraceutical value, and converting them into biofuels such as biogas, biodiesel, and bioethanol. Special focus is given to methods involving enzymatic hydrolysis, fermentation, and chemical extraction to isolate proteins, peptides, amino acids, sugars, and polyphenols. By analyzing emerging applications and industrial scalability challenges, this review highlights BSG’s growing role within circular economy models and its potential to promote sustainable innovations in both the brewing industry and the wider bioeconomy. Full article

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. Full article

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 E_a < 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. Full article

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. Full article

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. Full article