The accumulation of value-added coproducts and the reduction of lignin levels are two essential traits for lignocellulosic biomass intended for bioenergy applications. Sorghum is a premier bioenergy crop candidate, distinguished by its substantial biomass productivity, minimal nutrient needs, and resilience to heat and drought. Brown midrib (BMR) mutants, genetic variants characterized by naturally low lignin content, are particularly promising due to their lower recalcitrance and higher polysaccharide content. While various genetic engineering strategies have been used to enhance the amount of high-value coproducts in sorghum, these traits have not been combined with low-lignin characteristics. We generated new sorghum lines by crossing engineered varieties that accumulate the coproducts protocatechuate (DHBA) or 4-hydroxybenzoate (4-HBA) with a low-lignin BMR line. These lines were field-tested at two different locations to determine biomass composition and yields. Findings indicated that DHBA production remained stable when stacked with the BMR trait, which also preserved low lignin levels without negatively impacting biomass yield. Conversely, the combination of 4-HBA accumulation and the BMR trait led to yield losses relative to the unmodified BMR and reduced 4-HBA titers under certain growth conditions. While this research demonstrates that stacking low lignin with coproduct accumulation in sorghum is feasible, further investigation into the specific cultivation conditions of the modified crops remains necessary to optimize biomass yields and coproduct titers.
This bibliometric and critical review examines the evolution of scientific research on biochar application in energy-crop systems, emphasizing biomass productivity, soil quality, and soil carbon sequestration from 2007 to 2025. The bibliometric assessment comprised 409 records retrieved from the Web of Science Core Collection and integrated publication trends, thematic evolution, scientific collaboration networks, and agronomic and environmental evidence. Scientific production increased markedly during the period, despite interannual variability, accompanied by a shift from biochar production and physicochemical characterization toward field-scale agronomic performance, soil–biochar interactions, pyrogenic carbon persistence, life-cycle assessment, greenhouse gas mitigation, and engineered biochars. Physicochemical characterization nevertheless remained essential for interpreting biochar functionality. Field evidence indicates that crop responses depend on feedstock origin, pyrolysis conditions, biochar properties, application rate, soil characteristics, crop species, and experimental duration. Long-term studies and assessments of pyrogenic carbon stability support the potential of biochar to increase soil carbon stocks and contribute to durable carbon sequestration, although the magnitude and permanence of these effects vary across pedoclimatic conditions and management systems. Major research gaps include limited standardization of biochar characterization, insufficient long-term field validation under tropical conditions, incomplete evaluation of the environmental safety of modified biochars, and the absence of harmonized indicators integrating biomass productivity, soil carbon dynamics, greenhouse gas emissions, and carbon permanence. Overall, current evidence supports biochar as a soil amendment and carbon-management strategy for low-carbon bioenergy systems when material properties and application practices are aligned with site-specific agronomic constraints and validated under representative field conditions.
The financial potential of Napier grass (Pennisetum purpureum) as a feedstock for biogas-based electricity generation was evaluated by integrating field-derived biomass-yield and specific methane-yield datasets with a farmer-level economic analysis in a tropical coastal region of southern Thailand. Four species—Dwarf, Pak Chong 1, Bana, and Suvarnabhumi (a newly developed Thai species)—were cultivated under two fertilization treatments and three harvest intervals (60, 90, and 120 days). The system was assessed for sustaining a 1 MW biogas power plant, incorporating transportation distances of 10–30 km and key financial indicators, including Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PBP). The results showed that SV-F52-C60 required the smallest cultivation area (134 ± 34 ha) and was retained as the integrated system-level recommendation, whereas PC-F52-C90 achieved the highest farmer-level financial return. Under the high biomass-price scenario of 42.86/t and a transportation distance of 10 km, SV-F52-C60 generated a net profit of3,748/ha/year, with an NPV of 21,526/ha, an IRR of 241.7
Bioenergy and biofuels sourced from biomass are recognized as sustainable, renewable alternatives to fossil fuels, with the potential to reduce greenhouse gas emissions. This study explores how the circularity and sustainability of the biomass supply chain can be evaluated, specifically focusing on rice straw utilization in Vietnam, a topic that has not been comprehensively explored. To assess different sustainability and circularity supply chain alternatives for biomass to enhance utilisation of it for energy production in the Vietnamese agriculture context, an integrated Decision Support System based on a life cycle thinking approach and the multi-criteria decision making methods is employed. The study examines five supply chain alternatives for utilizing rice straw in bioenergy production in Vietnam, including anaerobic digestion for biogas and use in a CHP plant. Key sustainability and circularity indicators were analysed, including Global Warming Potential, Internal Rate of Return, job creation, and waste recycling rates. The results showed that the digestate pyrolysis alternative achieved the highest scores for sustainability and circularity. The captured and liquefied CO₂ alternative exhibited the lowest Global Warming Potential at 2.27 k.ton gCO₂eq/year, while the microalgae alternative had the highest GWP at 107 k.ton gCO₂eq/year. The digestate pyrolysis alternative also yielded the highest IRR at 20.46
