Global Change Biology Bioenergy最新文献

Understanding nitrogen-use strategies in Miscanthus sinensis is essential for optimizing biomass production while minimizing environmental impact, and providing sustainable bioenergy and ecosystem services. Nitrogen recycling in M. sinensis is known to be efficient, but the extent of intra-specific variability and its translation into distinct functional strategies remain unknown to date. Our objective was to assess the intergenotypic variation in nitrogen uptake and recycling and their relation to biomass yield in a diploid M. sinensis progeny. Endogenous remobilization fluxes were calculated for 80 genotypes from seasonal nitrogen dynamics under nitrogen deficient conditions, showing substantial intergenotypic variation, ranging from 0.2 to 85 kg N ha⁻¹ in spring and 5 to 158 kg N ha⁻¹ in autumn. Recycling efficiency, defined as the remobilized nitrogen relative to maximum nitrogen quantity, did not correlate with biomass yield, indicating that nitrogen recycling was independent of plant size. Exogenous nitrogen uptake varied widely (5–241 kg N ha⁻¹) and was strongly correlated with biomass yield (r = 0.72), making it the dominant factor influencing productivity, while principal component analysis highlighted the contribution of nitrogen recycling traits. Three functional groups emerged from hierarchical clustering on the principal components. The first group comprised nitrogen-acquisitive genotypes with high uptake and productivity, suitable for low-input bioenergy systems and potential ecosystem services like nitrate removal in water catchment areas. The second group followed a conservative strategy, with efficient belowground nitrogen storage and endogenous recycling, supporting resilience to environmental stress. The third group comprised nitrogen-deficient genotypes with low uptake, remobilization, and productivity. These findings demonstrate that substantial variation in nitrogen economy traits defined distinct functional groups in M. sinensis, providing a framework for breeding ideotypes that sustain biomass under nitrogen-limited conditions through enhanced uptake or remobilization, while delivering ecosystem services through contrasting remobilization strategies that can support nutrient retention, soil nitrogen conservation, and water quality regulation.

Miscanthus is a particularly promising lignocellulosic biomass as it can also grow under marginal conditions and can be used for a wide range of products including energy and material applications. The latter, including applications in the construction, textile, chemical, or agricultural sector, is becoming increasingly relevant today. In general, it is hypothesised that biobased products are advantageous in terms of their greenhouse gas (GHG) performance when compared to conventional—in particular fossil—alternatives. To investigate this, the life cycle assessment methodology is typically applied. However, assessments are subject to uncertainty and variability due to assumptions and methodological choices. Given the increasing interest in miscanthus-derived material applications, this study aims to draw more general conclusions about their GHG performance and relative mitigation potential. This should support a better understanding of their contribution to climate change mitigation objectives and guide the selection of promising products or product groups. A systematic review of peer-reviewed literature was conducted. In total, 20 studies reporting on 188 comparisons of the GHG performance of miscanthus-derived and alternative products were assessed. Most comparisons indicated potential GHG mitigation through miscanthus-derived products, with the majority ranging between 20% and 100% savings. Key parameters defining the relative performance include the selection of the reference product, consideration of soil carbon changes, changes in product and process design, as well as the incorporation of indirect Land Use Change (iLUC) impacts. Overall, we conclude that miscanthus-derived material applications have the potential to contribute to GHG emission mitigation if iLUC effects are minimised. Given the limited availability of agricultural land, miscanthus-derived products with high absolute GHG mitigation potential per unit of biomass used and long product lifetime are preferable. For future development, potential environmental trade-offs need to be monitored.

The cultivation of sterile giant miscanthus (Miscanthus × giganteus, M × g) for bioenergy and bioproducts has expanded into grain-cropped land in the United States (US) as local markets developed for this high-yielding perennial grass (10–30 Mg DM ha⁻¹). However, the magnitude of spatial and temporal variability in yield within US Corn Belt fields, along with impacts on economic return and sustainable land management, is poorly understood. This study established a diagnostic model relating remote sensing-derived vegetation indices to ground truth data from 105 hand-harvested stem biomass samples, which were strategically selected to represent the full range of vegetation index observations. The high-resolution satellite-sensed vegetation indices captured > 90% of the yield variation measured within fields. This model was then used to predict yield variability and assess economic performance across four of the first commercial M × g fields in the Corn Belt state of Iowa, US. Significant spatial variability in biomass dry matter (DM) yields (9.3–18.1 Mg DM ha⁻¹) and net profits ($83 to $1211.5 ha⁻¹) was observed. All fields were profitable in all site-years. When low profit occurred, it was explained by limited management experience of the crop in Iowa. The breakeven yield at a selling price of $130 Mg⁻¹ varied from 9.0–12.1 Mg ha⁻¹ at 15% moisture content (7.6–10.3 Mg DM ha⁻¹). Breakeven prices ranged from $73 to $122.4 Mg⁻¹, matching ranges used in the Department of Energy Billion Ton Report (US Department of Energy, 2023). Notably, M × g yield and profits were commensurate with grain crops particularly with favorable precipitation. This study provides insight on the M × g management “learning curve”, performance on marginal land and in drought conditions, and demonstrates that addressing yield gaps, reducing costs, and implementing precision agriculture strategies can enhance profitability. These findings emphasize the value of remote sensing technologies in guiding sustainable and competitive commercial-scale M × g production.

Increasing the production of bioproducts from lignocellulosic feedstocks requires improvement in both field production and biorefinery efficiency. When plant traits arise that improve field production but decrease biofuel yield, these trade-offs can represent challenges in the entire production process. To examine trade-offs between field and production traits, we examined factors underlying switchgrass resistance to fungal rust pathogens in field conditions and factors that impede yeast fermentation in the lab using repeated measurements on a switchgrass genetic diversity panel. We found that the same switchgrass genotypes that showed high fungal pathogen resistance also showed recalcitrance to yeast fermentation. These switchgrass genotypes were mostly from the Atlantic genetic group, which had high levels of specialized metabolites of the saponin class. Among 1589 metabolites identified through metabolomics, we found that saponins were among the most likely to explain variation in both rust infection and fermentation yield using random forest feature selection, and that only four of these were sufficient to explain 57.9% of the variation in rust susceptibility. Through follow-up testing in recalcitrant biomass, we found that the bacterium Zymomonas mobilis does not suffer the same inhibition as the yeast Saccharomyces cerevisiae, and that the addition of ergosterol (thought to be the fungal cellular target of saponin inhibition) rescues yeast fermentation. Several lines of evidence point to a central role for saponins as key metabolites protecting switchgrass from fungal pathogens and interfering with yeast fermentation, underscoring an ongoing need for collaboration between plant breeders and biofuel production scientists.

This work investigates the potential for logging residues (branches and tops that can be extracted during roundwood harvesting) to replace fossil-based feedstocks and energy use in industry, using Sweden as a case study. National and regional supply–demand balances are calculated and costs for extraction and transportation of logging residues to current and future users are estimated. The results show that there is an excess of unutilized logging residues in northern Sweden (just below 10 TWh/y), while the supply potential is already utilized in the south. In southern Sweden, the use of logging residues for district heating is extensive, while simultaneously, the refinery industry is undergoing a transition to renewable feedstocks. This creates a gap between the regional supply and demand of around 15 TWh/year going into the future. Meanwhile, the middle and northern parts of Sweden could be largely self-sufficient and rely on regional logging residues to supply the estimated future biomass demands of around 9 TWh/y. Thus, a regional supply–demand imbalance can be expected in the future, where the excess resource is located in the north, while large demands are expected in the south. With current utilization patterns, the costs for logging residue extraction and transportation are around 50% higher in the north than in the south of Sweden, mainly attributable to the shorter transportation distances. To supply refineries with logging residue-based feedstock from northern Sweden, costs for transportation can be reduced by about 5–10 €/MWh utilizing distributed methanol synthesis before long-distance ship and train transportation. However, the transportation cost reduction is small compared to the cost of the methanol synthesis step, highlighting that the added value for the refinery of receiving methanol compared to chipped logging residues needs to make up the difference to motivate a supply chain based on distributed methanol synthesis.

Biomass waste gasification is widely recognized as a sustainable and efficient method for converting organic waste into valuable energy, making it a focal point in global research. This study conducts a bibliometric analysis of publications related to this field, focusing on articles indexed in the Elsevier Scopus database from 1977 to 2023 using search terms “biomass waste,” “biomass residue,” “waste biomass,” and “gasification”. Initially, 981 articles were identified, with subsequent refined analyses narrowing the focus to 592 publications, using VOSviewer for in-depth examination. The analysis revealed that the year 2023 saw the highest publication count with 73 articles, followed by the year 2022 and the year 2020, with 61 and 54 articles, respectively. China, the USA, and India emerged as the leading contributors, accounting for 9.68%, 7.07%, and 6.75% of the total publications, respectively. Top institutions by citations are the University of Saskatchewan (259), Hamad Bin Khalifa University (169), and Paul Scherrer Institut (113). The most prolific researchers in the field include Gulyurtlu, I., Cabrita, I., and Dalai, Ajay K., with citation counts of 1296, 1290, and 1020, respectively. The journals Energy, Fuel, and Energies were identified as authors' most preferred publishing choice with 26, 23, and 22 publications, respectively. The keywords “Gasification,” “Biomass,” and “Syngas” were the most frequently occurring, with 194, 147, and 52 occurrences. Keyword analysis also revealed five thematic clusters. These findings offer a detailed overview of the research landscape in biomass waste gasification, emphasizing key contributors, emerging trends, and thematic areas, providing valuable insights for guiding future research in this domain.

Continuous-flow anaerobic digestion (AD) of wheat straw (WS) is often limited by volatile fatty acid (VFA) accumulation at low inoculum-to-substrate ratios (ISRs). Here, biochar (8.0 g/L) recovered methane production in overloaded systems (ISR 0.5, HRT 12 days), increasing yields by 658.45 mL/g-VS. Microbial analysis revealed a shift from Methanomicrobiaceae to Methanosarcinaceae dominance upon biochar addition, correlating with mcrA gene upregulation. This strategy enhances the AD of refractory feedstocks without diluting the organic load. The results offer insights into optimizing biogas systems treating low-biodegradability feedstocks at low ISRs, highlighting biochar's potential to stabilize performance and enrich functional microbial communities under stress conditions.

Perennial biomass crops represent a rapidly deployable technology to contribute to climate change mitigation, both reducing greenhouse gas emissions through providing alternative energy sources to fossil fuels, and direct photosynthetic removal of CO₂ from the atmosphere and sequestration into biomass and soil organic carbon (SOC). The giant perennial grass, Miscanthus × giganteus is one of the leading commercial crops currently deployed at scale, with its associated overwinter leaf litter production and decomposition providing a key pathway to SOC sequestration. However, challenges in the scalability of propagative material from this sterile, naturally occurring hybrid have led to great interest from breeding programs to develop novel varieties better suited to replication and specific end-use requirements. This study compares leaf litter production and decomposition from six Miscanthus genotypes to better understand their comparative potential contribution to carbon cycling across a range of morphologies. Our results showed that, despite genotypic differences in growing season leaf production, differences in overwinter retention rates resulted in similar absolute amounts being dropped to the ground, excepting M. × sinensis (our sinensis × sinensis hybrid) which both produced and dropped significantly greater litter material than the other genotypes, 14.9 Mg DM ha⁻¹ compared with an average across the other genotypes of 2.8 Mg ha⁻¹, and was associated with one of the lowest decomposition rates. Major shifts in the litter microbiome were observed during the first 6 months of decomposition with important plant material decomposers likely migrating from soil communities; these changes appeared to be statistically consistent across all genotypes. Excepting M. × sinensis, the relative consistency of litter production suggests that breeding programs may focus on yields without paying a penalty in leaf carbon cycling, though if outright leaf litter production for carbon sequestration and soil surface protection were the primary goal, M. × sinensis may represent an optimal choice.

Chilling temperatures are a major constraint on the early-season performance of C₄ bioenergy crops in temperate regions. To dissect the temporal architecture of chilling resilience, we conducted an integrative, time-resolved analysis of two Miscanthus sinensis genotypes contrasting in chilling tolerance, Ms12 (LCT) and Ms16 (HCT). Through stepwise chilling and recovery treatments, we profiled genotype-specific changes in shoot physiology, hormone accumulation, gene expression, and importantly cell wall composition, a key yet understudied determinant of chilling resilience in perennial grasses. The high chilling-tolerant genotype (HCT) maintained its shoot growth, photosynthetic performance, and membrane stability by activating a delayed but sustained program involving secondary wall reinforcement, ABA–JA hormonal crosstalk, and raffinose family oligosaccharide (RFO) accumulation in response to the extreme conditions. While, low chilling-tolerant genotype (LCT) initiated a rapid transcriptional and hormonal response, which lacked persistence and failed to support structural recovery or metabolic buffering. In-depth transcriptomic profiling revealed divergent dynamics between studied genotypes. The LCT genotype mounted an early transcriptional burst, while the HCT genotype showed prolonged induction of the cell wall biosynthesis, energy metabolism, and stress-response genes. FTIR (Fourier-transform infrared spectroscopy) and sugar quantification confirmed genotype-specific remodeling of cell wall polymers. Moreover, hormone profiling showed that only the HCT genotype sustained ABA and JA signaling through the recovery process. RFOs accumulation, tightly linked to transcriptional activation of GolS (galactinol synthase) and RS (raffinose synthase) genes, was also more pronounced in the HCT genotype. Our findings demonstrate that chilling resilience in M. sinensis depends not on early response magnitude, but on the integration and temporal coordination of stress mitigation and recovery pathways. This work establishes a multiscale framework for identifying traits and regulatory modules underpinning chilling tolerance in perennial grasses, with direct relevance to climate-resilient biomass plant breeding.