Global Change Biology Bioenergy最新文献

Nutrient inputs influence the sustainability of bioenergy crop production through contemporary (shortly after addition) and legacy effects (persisting over years) on microbial nitrogen (N) and carbon cycling, which contribute to greenhouse gas emissions. However, the relative importance of contemporary and legacy effects and how that could vary by crop functional types is poorly understood. Considering its rhizomatous roots and perennial growth, we hypothesized that Miscanthus × giganteus (M×g) would be more sensitive to legacy N fertilization and the historical context of its environment than an annual crop like maize. To test this hypothesis, we examined the effects of legacy and contemporary N inputs on nitrous oxide (N₂O) and carbon dioxide (CO₂) emissions, as well as key N cycling genes in soils where M×g and maize were grown. A 150-day soil incubation experiment was conducted using soils from a long-term M×g and maize fertility experiment with three historic N fertilization rates (0, 112, and 336 kg N ha⁻¹ year⁻¹) and a contemporary amendment (60 mg N kg⁻¹) with negative control (0 mg N kg⁻¹). We observed significant increases in cumulative N₂O emissions in Mxg soils relative to maize soils, particularly at higher legacy fertilization rates, while contemporary N had no significant effect. Bacterial amoA gene abundance, which plays a significant role in nitrification in nutrient-rich soils, also increased with higher legacy fertilization rates in M×g soils but was unaffected by the contemporary N. In maize soils, legacy and contemporary N did not significantly affect N₂O emissions, but cumulative CO₂ emissions and amoA gene abundance significantly increased. The abundances of norB genes were not significantly influenced by either legacy fertilization or contemporary N amendments in either soil. Our findings demonstrate the greater importance of fertilization history over contemporary N in mediating soil N₂O emissions, particularly for perennial bioenergy crops.

Miscanthus holds a promise as a biocrop due to its high yield, perenniality and ability to grow on infertile soils. However, the current commercial biomass production of Miscanthus is mostly limited to a single sterile triploid clone of M. × giganteus. Nevertheless, parental species of M. × giganteus, Miscanthus sacchariflorus and Miscanthus sinensis contain vast genetic diversity for crop improvement. With M. sacchariflorus having a natural geographic distribution in cold-temperate northeast China and eastern Russia, we hypothesised that it has substantial variation in physiological response to chilling. Using a semi-high-throughput method, we phenotyped 209 M. sacchariflorus genotypes belonging to six genetic groups for non-photochemical quenching (NPQ) and photosystem II efficiency (ΦPSII) kinetics under warm and chilling treatments in three growing seasons. In response to the chilling treatment, all genetic groups exhibited an increase in NPQ induction rate indicating faster activation of NPQ in light. Notably, under chilling, the Korea/NE China/Russia 2x and N China 2x groups stood out for the highest NPQ rate in light and the highest steady-state NPQ in light. This NPQ phenotype may contribute adaptation to chilling during bright, cold mornings of spring and early autumn in temperate climates, when faster NPQ would better protect from oxidative stress. Such enhanced adaptation could expand the growing season and thus productivity at a given location or expand the range of economically viable growing locations to higher latitudes and altitudes. A genome-wide association study identified 126 unique SNPs associated with NPQ and ΦPSII traits. Among the identified candidate genes were enzymes involved in the ascorbate recycle and shikimate pathway, gamma-aminobutyric acid and cation efflux transporters. Identifying natural variation and genes involved in NPQ and ΦPSII kinetics considerably enlarges the toolbox for breeding and/or engineering Miscanthus with optimised photosynthesis under warm and chilling conditions for sustainable feedstock production for bioenergy.

Chilling affects the productivity and geographical distribution of most crops. Using a semi-high-throughput approach to investigate photosynthesis-related traits, we characterised variation existing in the bioenergy crop Miscanthus under chilling and warm conditions and identified potential genes associated with it. Under chilling, two genetic groups from the northern edge of Miscanthus distribution stood out for faster activation of photoprotection. This trait may contribute adaptation to chilling in temperate climates, when faster photoprotection would better defend from oxidative stress. Enhanced chilling adaptation could expand the growing season and thus productivity or enlarge the range of growing locations.

Biochar amendments in rice-wheat systems are sustainable for reducing GHGs (greenhouse gases) and improving soil health but the widespread adoption of biochar faces economic challenges. To address limitation, a novel biochar-based urea was formulated for environmental and cost advantages. A pot experiment within a rice-wheat rotation was conducted to evaluate comparative effects of biochar-based urea (CKBU), biochar + urea (BCU), and biochar-based urea + biochar (BCBU) over conventional mineral fertilizer (CKU) on soil ammonia (NH₃) volatilization, GHG emissions, soil structure, and crop productivity. Furthermore, fertilizer N fate was tracked using the ¹⁵N isotope during wheat season. The results indicated that compared to CKU, CKBU, BCU, and BCBU treatments significantly mitigated NH₃ volatilization by 22%–31% during the rice season, and a 19% reduction was observed under the BCBU treatment during the wheat season due to the response of N-cycling microorganisms. Regarding GHG emissions, the CKBU, BCU, and BCBU treatments significantly decreased the global warming potential (GWP) value by 49%–55% during the rice season and by 26%–45% during the wheat season, compared to CKU. Additionally, CKBU enhanced ¹⁵N use efficiency by 29% during wheat season, without affecting the rice season. The economic performance indicated that applying BU alone offered a net economic benefit, whereas biochar amendment led to a net economic loss. However, biochar amendment improved SOC and aggregation structure, with a significant increase in macroaggregate distribution over 50% compared to CKU and CKBU. Therefore, BU with small portions of biochar can be as effective in reducing NH₃ emissions and mitigating GHG emissions as the use of a large quantity of biochar. Additionally, the BCBU did not show additional synergistic benefits regarding emission reduction or yield enhancement. Therefore, shifting biochar to BU could be a cost-effective approach to achieving sustainable productivity in rice-wheat crop rotation systems.

Wastewater treatment plants have two persistent financial and energetic drains, the carbon dioxide content of biogas, which limits its commercial sale, and the presence of trace organics in the wastewater effluent, which damages the aquatic ecosystem, like the Great Barrier Reef. Biogas is a renewable methane resource that is underutilized due to the variable CO₂ content (~40%). Biogas is energy intensive to purify and limited by the economy of scale (> 8.85 GJ/h) to large-scale purification methods, thus small-scale processes require development. Electrocatalytic microbes native to wastewater have been shown to convert CO₂ to CH₄ and acetate, however complete conversion of the CO₂ content to CH₄ is energy intensive. Here we show a low power bioelectrochemical fuel cell design to purify biogas to pipeline quality methane (98%), manufacture methane and/or acetate, and remove trace organics, using HCO₃⁻ as the transport charge carrier from dissolved CO₂ from the biogas through an anion exchange membrane. This decreased the power required to separate CO₂ from methane in biogas on a molar basis, resulting in a net energy recovery similar to current industrial systems. Magnesium anode use resulted in an energy positive system. Tests evaluated the influence of cathode potential on the current density, HCO₃⁻ ion flux and the rates and efficiencies of methane production, resulting in optimization at −0.7 V versus standard hydrogen electrode (SHE). A techno-economic analysis modeled a positive return on investment for scaled-up production to purify small biogas streams that are otherwise financially unrecoverable. Carbon sequestration by production of methane, acetate and solid fertilizers demonstrated profitable and energy efficient waste-to-resource conversion.

Practical strategies for bioenergy planning in the face of climate change should rely on ready-to-use yield projections. Perennial grasses grown in marginal lands (MLs) provide abundant feedstocks to be converted into different energy vectors. The aim of this study was to provide a model-based assessment of how much energy, in the form of biomethane and bioethanol, can be achieved by Miscanthus and giant reed across Italy. Marginal lands were here conceived as low profitable non-irrigated areas, without mechanization and/or nature conservation constraints. Marginal lands eligible for simulations were selected crossing environmental factors and ecological requirements of the two crops. The biophysical model Arungro was calibrated considering rainfed/full-irrigated systems using multiple-site and multiple-year datasets. The model was connected to a georeferenced database, with information on (i) current/future climate, (ii) agronomic practices, (iii) soil physics/hydrology, (iv) MLs, and (v) crop suitability to environment and simulations were performed at 500 × 500 m spatial resolution across all Italian regions. Under baseline conditions (i.e., 1981–2010), the total area of MLs available for energy crops (i.e., 49,100 km²) allowed to obtain 23,500 (giant reed) and 23,700 (Miscanthus) Giga-m³ CH4-STP of biomethane and 18,600 (giant reed) and 24,400 (Miscanthus) Giga-liters of bioethanol. While the amount of energy carriers is expected to increase, on average, of +4.6% in 2055 and + 0.4% (mean of +9.2%—South, −2.4%—Center, −5.4%—North Italy) in 2085 for Miscanthus, giant reed-based productions are projected to be more stable across the country and time frames (+6.7% in 2055; +2.8% in 2085). This study contributed to define a modular and detailed procedure aimed at quantifying attainable energy yields from bioenergy grasses in MLs. The consideration of fine-resolution multiple-scale heterogeneity allowed for an in-depth investigation of biomass productivity, attainable energy yields, and related stability under current/climate change scenarios, highlighting critical spots and opportunities within the country.

Abdalla, K., Uther, H., Kurbel, V. B., Wild, A. J., Lauerer, M., Pausch, J. 2024. Moderate Drought Constrains Crop Growth Without Altering Soil Organic Carbon Dynamics in Perennial Cup-Plant and Silage Maize. Global Change Biology Bioenergy 16:e70007, https://doi.org/10.1111/gcbb.70007

In the article by Abdalla et al. (2024), we found an error in the unit of soil organic carbon (SOC) stocks in Figure 3d–f. Specifically, the original unit was given as g C m⁻², but it should be kg C m⁻². In addition, it was not clearly stated in the figure legend that these data represent an average of 9 soil depths of 10 cm each (0–90 cm profile).

Another minor error in the unit of Figure 5b, where the unit of the microbial biomass nitrogen was given in mg C kg⁻¹ soil, which should be mg N kg⁻¹ soil.

We apologise for any inconvenience this error may cause.

Agricultural lands hold significant potential for CO₂ sequestration, particularly when utilizing biomass crops and agricultural residues. Among these, Miscanthus × giganteus (mxg) stands out due to its high productivity and carbon sequestration capabilities. Recognizing the importance of such biomass crops, the Intergovernmental Panel on Climate Change (IPCC) has identified Bioenergy with Carbon Capture and Storage (BECCS) as a crucial strategy for achieving net-zero CO₂ emissions by 2050. This study examines the carbon uptake potential of mxg during its establishment year at the Sustainable Advanced Bioeconomy Research (SABR) farm in Iowa, USA, where mxg was planted at a density exceeding previous studies. Using eddy covariance (EC) measurements, we quantified the net ecosystem carbon exchange (NEE), and derived gross primary productivity (GPP), and ecosystem respiration (R_eco). Our findings reveal that SABR's mxg exhibited a significant carbon uptake of −621 g C m⁻², a threefold increase compared to a similar EC site in the “corn-belt” (University of Illinois Energy Research Farm; UIEF), which was established with lower planting density and pre-commercial planting equipment. Favorable growing conditions and advanced planting technologies at SABR likely contributed to this high carbon uptake. Comparisons with other global EC studies indicated a strong correlation between higher planting densities and greater carbon uptake. These results suggest that increasing mxg planting density can enhance carbon uptake, but further studies are necessary to evaluate the impacts under varying environmental conditions and management practices. Additionally, economic analyses are essential to determine the viability of higher planting densities. Our study underscores the potential of optimized mxg management practices to contribute significantly to CO₂ uptake and supports the development of BECCS as a viable climate change mitigation strategy.

Thermochemical conversion of giant reed biomass during periodic variations has been carried out in a semi-batch tubular reactor at 550°C. This study was carried out after the incineration of giant reed along the river banks. Four periodic variations, late spring (HS-4), late summer (HS-1), late autumn (HS-2), and late winter (HS-3) were considered to investigate the effect of harvest time on biomass fuel properties, pyrolysis product distribution, non-condensable gas characterization, and bio-oil organic phase (BOP) fuel properties. The considered biomasses herein had average calorific values of 18.86 ± 0.05, 19.73 ± 0.05, 19.23 ± 0.04, and 18.44 ± 0.04 MJ/kg during HS-1, HS-2, HS-3, and HS-4, respectively. The biomass, bio-oil organic phase, biochar, and pyrolysis gas were characterized using thermogravimetric analysis (TGA), gas chromatography–mass spectroscopy (GCMS), Fourier transform infrared spectroscopy (FTIR), micro-GC, and scanning electron microscopy (SEM/EDS). The organic phase of bio-oil was isolated using a 125 mL separating funnel, allowing natural stratification of the immiscible phases. BOP yield increased from 5 to 11 wt% during HS-4 and HS-3, respectively. Higher heating values (HHV) of the BOP ranged from 19.4 ± 0.03 to 22.6 ± 0.02 MJ/kg in relation to the active growth stage and senescence-dormant phase. Physical and chemical properties (TAN, density, viscosity, water content, and CHNS) and chemical compound groups of organic phase bio-oil were analyzed. The produced BOP was rich in phenolics for all considered periods. The effect of harvest time showed that biomass and bio-oil organic phase fuel properties are improved during the senescence-dormant period. As a result, giant reed biomass should be harvested during autumn to avoid incineration that releases carbon dioxide into the atmosphere and will also reduce the occurrence of artificial flooding.

Promoting the bioeconomy to aid in the achievement of sustainability goals has increased demand for biomass as feedstock. Residual biomass from agricultural production is an attractive option, as it is a by-product that does not compete with food production. However, crop residues are important for the preservation of soil quality, especially for the maintenance of soil organic carbon. Therefore, their use can conflict with environmental goals and initiatives that aim to preserve soil fertility and carbon stocks. Nevertheless, the adoption of intermediate crops could compensate for the negative effects of crop residue removal. Moreover, if crop residues are used for a bioeconomy pathway such as biogas production, the resulting digestate derived from the anaerobic digestion process could be returned to the soil, providing an input of highly recalcitrant carbon. In this study, we modeled the effects of removal of crop residues, the cultivation of intermediate crops, and the application of digestate on Swedish soil organic carbon stocks. Our results suggest that the inclusion of intermediate crops could raise the carbon stocks at equilibrium by an average of 1.93 t C ha⁻¹ (~3% increase) with a notable spatial variation. Digestate application showed a higher average increase (3.3 t C ha⁻¹, ~5%) with an even higher variation. The removal of crop residues was detrimental in some areas, resulting in a loss of carbon, which could not be compensated for entirely by the introduction of intermediate crops or digestate recycling. Combining these two practices showed overall positive effects on soil organic carbon stocks; however, the results cannot be generalized at any spatial location, and we emphasize the importance of assessments tailored to local conditions.

This study aimed to isolate, purify, and characterize a lipase from the gut symbiont Bacillus megaterium F25 (GenBank accession: MF597792) of the aquatic insect Rhantus suturalis, with a focus on its potential applications in biodiesel and food industries. Under optimized culture conditions, B. megaterium F25 could produce 583 U/L of lipase in shaking flask culture. The purified lipase (PL) exhibited a specific activity with 113.89 U/mg, and its molecular weight was determined as 34 kDa. The activity of PL was enhanced by methanol, ethanol, Tween-80, Triton X-100, Ca²⁺, and Mg²⁺, while β-mercaptoethanol, EDTA, SDS, Fe²⁺, Mn²⁺, and Cu²⁺ were inhibitory. PL showed optimal activity and stability at neutral and slightly acidic pHs, as well as in a temperature range of 20°C–30°C. PL displayed strong hydrolytic activity toward plant oils and animal fats, indicating its potency for both the food industry and the remediation of oil-contaminated environments. When tested as a catalyst, PL provided biodiesel production with a transesterification yield of 86.8% under optimized conditions (36 h reaction time, 4 mL enzyme solution, 30°C, pH 7.0, and waste cooking oil:methanol ratio of 10 mL/40 mL). This is the first report on the lipase-producing potential of gut microbial symbionts of aquatic insects. Furthermore, B. megaterium lipase was tested for the first time as a biocatalyst for biodiesel production.