Global Change Biology Bioenergy最新文献

The global shift towards clean energy emphasizes waste valorization as a key to achieving sustainable development goals. Biomethane production from organic waste not only converts waste to energy but also reduces greenhouse gas emissions. The growth trajectory of sustainability and environmental protection highlights the significance of energy valorization in anaerobic digestion to produce biomethane and digestate. A 2019 UN report noted that 17% of global food production, equating to 1.0 billion tons, became waste, with major contributions from food waste (61%), households (26%), and food services (13%). The value derived from biomethane, carbon dioxide, nitrogen, ammonia, and manure underscores the need for economically sustainable valorization pathways to attract investment and ensure market viability. Research into purifying biogas for diverse applications has advanced, with technologies such as membranes, genetic manipulation, and metabolic engineering showing potential for improving biogas conversion. Enhanced membrane technologies promise improved biogas quality and efficiency. This review focuses on developing a microscale biogas purification plant and examining processes such as amine scrubbing, absorption, adsorption, and membrane separation as promising methods.

Saccharina japonica, one of the most widely cultivated brown algae species, is considered a promising biorefinery feedstock due to its high carbohydrate content. Dilute acid hydrolysis can be performed to recover sugars from S. japonica; however, the impact of sugar derivatives (potential inhibitors) generated during the hydrolysis process on lactic acid production remains unexplored. In this study, the inhibitory effects of sugar derivatives on the fermentation performance of Lacticaseibacillus rhamnosus were systematically examined to enhance the bioconversion efficiency of S. japonica. Firstly, the sugar derivatives present in S. japonica hydrolysate were identified, revealing the presence of acetic acid, formic acid, and furfural. Subsequently, their inhibitory effects on lactic acid production were assessed, demonstrating significant inhibition (p < 0.05) at the following concentrations: > 2 g/L acetic acid, > 0.5 g/L formic acid, and > 1 g/L furfural. Based on the information, 5% H₂SO₄ was determined to be the optimal solvent for S. japonica hydrolysis, enabling the production of hydrolysate with high fermentable sugar content and minimal sugar derivatives: 23.23 g/L mannitol, 0.86 g/L glucose, 0.21 g/L acetic acid, 0.14 g/L formic acid, and no detectable furfural. The resulting S. japonica hydrolysate contained sugar derivatives at non-inhibitory levels, allowing for direct application to fermentation without detoxification. As a result, lactic acid production and yield were determined to be 18.26 g/L and 92.3%, respectively, comparable to the control group (17.32 g/L and 87.6%). This study addresses a critical knowledge gap in the bioconversion of macroalgae to lactic acid by elucidating the effects of sugar derivatives on fermentation performance.

The accumulation of small-diameter and low-value trees and logging residues can negatively impact forest health by increasing the risks of pests, diseases, and wildfires. Biochar production presents a potential solution by creating markets for these underutilized resources. However, there is limited information on market dynamics and the influence of subregional conditions on the use of forest biomass for biochar. The study identified potential locations for biochar production and developed procurement zones using delivered wood prices to evaluate biomass availability and biochar application. The minimum selling prices (MSP) for biochar were calculated for local applications to assess the cost savings. Under a baseline scenario with an average delivered biomass price of $23.25 per green ton, stationary facilities produced 71% more biochar than the estimated requirements in the Upper Peninsula (UP) but only 10% more in the Lower Peninsula (LP). Portable units, however, produced less biochar than the required application in both regions, with deficits of 4% in the UP and 50% in the LP. While stationary facilities are more cost-effective and scalable, portable units can procure more biomass and offer greater opportunities for land application of biochar. Despite a lower MSP for stationary facilities, portable units could provide a more economical option by reducing investment costs and risks. The study recommends establishing portable units in the UP and stationary facilities in the LP to optimize forest biomass procurement and biochar production in Michigan. This analysis contributes to understanding resource availability and the potential utilization of forest biomass for biochar in Michigan.

In the last two decades, several studies have utilized biogeochemical models to evaluate the impact of different edaphoclimatic conditions on soil carbon storage and the dynamics of soil organic carbon. At the same time, biochar, a carbon-rich material obtained from the pyrolysis of biomass residues, has been identified as a promising carbon sequestration material. However, current models do not adequately incorporate the role of biochar in soil management. In this context, the current state of research on biogeochemical models that include the entry of biochar into soil has been characterized. The research indicated that the development of studies on the topic “biochar” is widely explored, with 4259 papers being identified using the first search filter. Specifically, searching for studies that mentioned terms related to biogeochemical models for estimating soil carbon stock, it was observed that a small number of the studies (N = 46) considered the entry of biochar into the models. Although most studies have used the RothC model to simulate biochar within biogeochemical models, biochar inputs have also been implemented in APSIM, EPIC, Century, DNDC, and other models, including those not primarily focused on soil carbon stock estimation. Among these studies, the minority included the results of calibration and validation of the models, which are paramount for the model's credibility. Therefore, efforts must be concentrated on solving the lack of valuable data to validate the models. Data from long-term field experiments that consider interactions between crop and climate conditions are highly desirable. The possibility of increasing carbon stocks by incorporating biochar into the soil could promote environmental and financial gains, and biogeochemical models that consider the incorporation of biochar are valuable tools for decision-makers.

While burning wood for heat and electricity constitutes the largest source of renewable energy in the EU, forest biomass harvesting is weakening the EU's forest carbon sink, and some Member States have lost their net forest sink completely, including heavily forested countries like Estonia and Finland. A European Commission 2016 impact assessment for bioenergy under the EU's Renewable Energy Directive predicted the forest sink would shrink as biomass use increased, even if sustainability criteria were required. Nonetheless, the EU adopted criteria that consider “sustainable” forest biomass to have zero carbon emissions, rendering EU and UK treatment of biomass inconsistent with IPCC's Guidance for National Greenhouse Gas Inventories. Renewable energy incentives have increased biomass use for electricity generation 1100% since 1990, but residential heating, which is ungoverned by any criteria, still represents the largest use of wood for energy in the EU. Incentives for bioenergy with carbon capture and storage (BECCS), which is intended to deliver “negative emissions,” will likely increase pressure on forests. Although IPCC Guidance is clear that BECCS fueled with forest biomass does not remove net CO₂ from the atmosphere just because carbon has been stored belowground, EU and UK climate policies rely on large-scale deployment of BECCS to meet climate targets. Bioenergy use cuts across environmental, energy, and climate policy domains; thus, reversing the accelerating decline of the forest carbon sink will require significantly better integration of renewable energy policies with climate targets and ensuring that biomass policies are aligned with international emissions reporting. Policymakers can reduce pressure on forests by disqualifying forest biomass from counting toward renewable energy targets, reducing subsidies for wood-burning, and adopting forest management policies that prioritize carbon sequestration and biodiversity. Reducing biomass harvesting and reallocating the billions currently spent on bioenergy subsidies to solar, wind, and geothermal energy is essential for restoring forests and achieving climate targets.

Industrial crops grown on marginal lands offer a potential source of low-iLUC feedstock for bio-based industries, supporting sustainable bioeconomic development. However, marginal-land-based bioeconomy systems face significant uncertainties at early stages, such as limited data, farmers' hesitancy to adopt novel crops, undeveloped markets and immature technologies. This study implements an integrated multi-criteria framework as a structured, multi-step approach to connect bio-based value chain components and stakeholders in marginal-land-based bioeconomy systems at the research level. The framework was applied within the EU Horizon project MIDAS to identify, evaluate and combine bio-based value chain components, with a case study in the Swabian Alb (southern Germany) demonstrating its potential for designing scalable bio-based value chains tailored to regional conditions. Key findings emphasise the importance of stakeholder collaboration, iterative design processes and context-specific criteria that address technical, economic, social and regulatory aspects. The approach, based on qualitative data and stakeholder input, offers critical insights into the feasibility of biomass-to-product pathways and serves as a foundation for advanced research. Future research needs to focus on expanding data availability, incorporating quantitative methods, and addressing economic and market factors, such as stakeholder willingness to produce feedstocks, to enhance the scalability and robustness of the findings and facilitate the establishment of sustainable bioeconomy systems on marginal lands.

Sugarcane straw removal for bioenergy production—especially second-generation ethanol—is shown to be a promising pathway for decarbonization. However, indiscriminate straw removal can negatively affect soil-related ecosystem services (SES), compromising the sustainability of the associated bioenergy production. Here, a comprehensive literature review was conducted to select and quantify the changes in agronomic and environmental indicators affected by low (≤ 1/3), moderate (> 1/3 to ≤ 2/3), and high (> 2/3) straw removal levels and the consequential impacts on eight SES. A quali-quantitative approach was developed to generate an impact matrix that provides the direction of the effects (negative, neutral, or positive) and the associated confidence levels. Overall, the lowest impact on SES occurs under low straw removal with a neutral effect on C storage, nutrient cycling, weed control, greenhouse gas (GHG) mitigation, and provision of food and bioenergy. Water regulation, erosion control, and maintenance of soil biodiversity were the SES most negatively affected by straw removal. Moderate and high levels of straw removal negatively impact the maintenance of SES and compromise the sustainability of sugarcane cultivation areas, except for pest control and soil GHG emission mitigation. Finally, it was also discussed how the negative impacts of straw removal on SES could be mitigated or even reversed through the adoption of best management practices, such as cover crops, organic amendments, biological products (e.g., use of phosphate-solubilizing bacteria and mycorrhizal fungi), reduced tillage, and machinery traffic control. Ultimately, the results of this study can be useful to guide decision-making by farmers, investors, stakeholders, and policymakers toward sustainable bioenergy production that contributes to a low-carbon economy and climate change mitigation.

The presented research is focused on evaluating the influence of adding clinoptilolite (Z) on the multi-component co-digestion (AcoD) of sewage sludge (SS), citrus waste represented by orange peel (OP) and brewery spent grain (BSG). The experiments were conducted under mesophilic conditions at 37°C in batch mode; 7 series with differing feedstock configurations were performed. The positive effect of Z was shown in each configuration, most strongly with SS:OP:BSG:Z. The production of methane was enhanced by 81%, in comparison to the co-digestion of SS:OP:BSG without Z, reaching 362.4 mL CH₄/g volatile solids (VS). The kinetics was also improved as the methane production rate increased to a similar extent, amounting to 17.3 mL CH₄/g VS d. Moreover, it was observed that the lag phase was shortened and the contents of both limonene and phenols were reduced. The composition of the microbial communities was significantly altered by the addition of Z in AcoD of SS:OP and SS:OP:BSG. Therein, a unique microbiome structure with the highest percentage of unidentified sequences was found. The beneficial effect of Z was multifaceted and related to the reduction of the stress caused by the presence of limonene and phenols as well as the syntrophic relation between the microorganisms.

The torrefaction process for producing biochar from waste biomass has garnered significant attention in recent years. However, economic constraints hinder the broader adoption of this process. One such constraint is the requirement for an inert atmosphere during torrefaction. This study aimed to evaluate the feasibility of torrefying vineyard pruning waste in an oxygen-rich environment. Torrefaction of waste vine shoots was conducted in a fixed-bed reactor, utilizing a carrier gas medium with varying O₂ concentrations (0% to 21%) at process temperatures of 220°C, 250°C, and 280°C. Proximate and elemental analyses revealed that the torrefaction temperature is the key variable influencing biochar yield. Moreover, under mild torrefaction conditions, an increase in the carrier gas O₂ concentration had a lesser impact on product yield compared with process temperature. Thus, it can be inferred that combustion gases and gases generated under mild torrefaction conditions could serve as carrier gases for a more cost-effective torrefaction process. Under oxidative conditions, the total biomass energy recovery was measured at 87.3% ± 1.7% for low temperatures and short torrefaction durations.

Optimizing harvest time has a significant impact on biomass productivity and combustion quality, making it essential to produce sustainable solid biofuel from perennial grasses. This study was conducted to determine the optimum harvest time in tall wheatgrass for the production of solid biofuel in a semi-arid Mediterranean environment by evaluating the effects of six different harvest times (November, January, March, May, July, and September) on biomass yield and combustion quality parameters over two growing seasons. Dry matter yield of the crop steadily increased from the November to May harvest, which approximately coincided with the end of the growing season, but then it was significantly reduced by both the July and September harvests. Additionally, the content of cell wall components (lignin, cellulose, and hemicellulose) and the lignin/holocellulose ratio gradually increased with the progression of maturity and senescence. In contrast, ash, moisture, and mineral (N, P, K, Ca, Mg, S, Si, Cl, Na, and Zn) contents tended to decrease from the May to September harvest. In this regard, the September harvest significantly improved combustion quality by reducing the contents of ash, mineral, and moisture, the risks of slagging, aerosol formation, and corrosion, and increasing the lignin content and lignin/holocellulose ratio, despite causing a 22% yield loss in comparison to the May harvest. These results suggest that the September harvest may be primarily preferred for the sustainable solid biofuel production from tall wheatgrass in the dry marginal lands of the Mediterranean region.