BioEnergy Research最新文献

Second-generation (2G) bioethanol is a promising alternative energy source because it can reduce greenhouse gas (GHG) emissions that contribute to global warming and does not compete with food production. Several 2G bioethanol production strategies have been developed to enhance the efficiency of the production process. Integrated consolidated bioprocessing (ICBP) is the latest method, combining pretreatment and consolidated bioprocessing (CBP) in a single reactor. This research focuses on producing bioethanol from rice straw using the ICBP method and evaluating its environmental impacts. Four rice straw management scenarios, including open burning, landfilling, conventional bioethanol production, and ICBP bioethanol production, were conducted to compare their environmental performance using life cycle assessment (LCA). The results indicate that the ICBP method can produce bioethanol at a concentration of 10.85 g/L for 29 days. For every 1 ton of rice straw, the bioethanol production scenario offers greater environmental benefits compared to the baseline scenarios of open burning and landfilling. Bioethanol production using the ICBP method reduces global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), human toxicity potential (HTP), and photochemical oxidation creation potential (POCP) by 28.27%, 29.18%, 22.73%, 24.22%, and 41.18%, respectively, compared to conventional bioethanol production. The ranking of rice straw management scenarios based on environmental benefits is as follows: ICBP bioethanol > conventional bioethanol > landfilling > open burning.

Annually, over 92 million metric tonnes (Mt) of textile waste are produced globally, with 17 Mt discarded in the US alone. Textile waste is typically comprised of approximately 50% biomass-derived cellulosic fiber and 50% fossil carbon-derived synthetic fiber, with the biogenic portion representing a global CO₂ removal capacity estimated at 75 Mt CO₂ (14 Mt CO₂ in the US alone). Bioenergy with carbon capture and storage (BECCS) offers a promising solution for permanently removing atmospheric CO₂ by converting biomass into energy while capturing and storing the resulting carbon emissions. Despite its potential, textile waste remains an underutilized feedstock in BECCS research and deployment. This study evaluates the techno-economic feasibility and environmental performance of small-scale modular BECCS systems that process textile waste to produce electricity and achieve net-negative emissions. Four waste-to-energy scenarios were modeled using 100% cotton or a 50/50 cotton–polyethylene terephthalate (PET) blend, with and without carbon capture. In 2018, the US EPA reported that 66% of discarded textiles were landfilled. As a result, a fifth landfilling end-of-life scenario was introduced to compare valorization scenarios to a baseline scenario. Life cycle assessment (LCA) and techno-economic analysis (TEA) are applied to quantify levelized cost of electricity (LCOE) and CO₂ removal. For 100% cotton waste, the removal cost was 329 USD per metric ton (t) CO₂e, significantly lower than 777 USD per t-CO₂e for 50/50 cotton-PET. The carbon removal efficiencies of 100% cotton and 50/50 cotton-PET textile waste materials were 91% and 59%, respectively. The lowest LCOE was observed for a 50/50 cotton-PET mixture with CCS at 0.17 USD/kWh, due to the relatively high energy density of the feedstock. In contrast, 100% cotton with CCS had the highest LCOE at 0.29 USD/kWh due to the lower feedstock energy density, higher capital expenditure (CAPEX), and reduced CO₂ sales, due to the lower carbon content in cotton compared to PET. In addition, the LCOE for the 50/50 cotton-PET without CCS was 0.18 USD/kWh and the LCOE for the 100% cotton without CCS was 0.24 USD/kWh. The LCA with CCS showed that direct and indirect emissions lead to high acidification potential due to ammonia release via monoethanolamine (MEA) degradation, compared to electricity production without CCS. Additionally, the production of MEA itself exhibited high ecotoxicity potential compared to other process inputs such as NaOH and activated carbon. Overall, this study demonstrated textile waste’s potential as a viable alternative for producing bioenergy and waste-derived energy. In terms of overall environmental impact, all four valorization scenarios significantly outperformed landfilling.

Agricultural residues such as pods from cocoa, flamboyant, and locust bean plants represent abundant yet underutilized biomass wastes that contribute to environmental challenges when improperly managed. Converting such residues into biochar provides a sustainable approach for waste valorization and carbon sequestration. However, the high moisture and volatile contents of these residues often reduce gasification efficiency and limit biochar quality. This study investigates the influence of low-temperature pre-devolatilization on the yield, structure, and physicochemical properties of biochars derived from flamboyant (FPD), cocoa (CPD), and locust bean (LPD) pods. Each devolatilized biomass was carbonized in a biofuel-powered top-lit updraft (TLUD) gasifier with retort heating. The resulting biochars were characterized using BET, SEM, FTIR, TGA, and EDX analyses. Results showed yields of 72%, 69.4%, and 66.77% for FPD, LPD, and CPD, with BET surface areas of 542.265 m²/g, 450.023 m²/g, and 371.958 m²/g for CPD, FPD, and LPD. The biochars exhibited mesoporous structures with well-developed interconnected pores and diverse functional groups, including hydroxyl, carboxyl, and aromatic moieties. Elemental analysis revealed carbon and sodium as predominant components with minor mineral inclusions. These results demonstrate that pre-devolatilization improves the physicochemical quality of pod-derived biochars and supports their potential application in adsorption, catalysis, and soil amendment within circular bioeconomy frameworks.

This work presents an easy and less polluting routine for obtaining bacterial polyhydroxybutyrate (PHB-B), using low-cost inputs. The objective of this research is to evaluate the thermal and thermodynamic properties of PHB-B obtained from the bacterium Cupriavidus necator and commercial sugarcane molasses substrate. Commercial PHB Biocycle^® (PHB-C) was also evaluated for comparative purposes. The thermal properties of both biopolymers were similar. PHB-B showed a well-defined cold crystallization peak at 93.31 ± 0.68 °C, while PHB-C exhibited a broad peak at 61.28 ± 0.26 °C. The degrees of crystallinity of PHB-B and PHB-C were 48.56 ± 0.49 and 54.72 ± 0.48%, respectively. PHB-B displayed a double melting peak at 158.43 ± 2.4 and 168.73 ± 1.32 °C, whereas PHB-C showed only one at 167.04 ± 0.82 °C. A crystallization temperature in the second heating of 44.65 ± 0.02 °C was observed only for PHB-C. The initial and maximum temperatures of thermal degradation were 192.39 ± 2.19 °C and 254.86 ± 1.37 °C for PHB-B, and 217.76 ± 1.80 °C and 261.89 ± 0.91 °C for PHB-C. In both cases, the degradation process occurred in a single step. The activation energy revealed that PHB-C is more resistant to thermal degradation than PHB-B. The thermodynamic parameters indicate that the thermal degradation profile is endothermic and that the thermal degradation processes are non-spontaneous for both biopolymers. This study demonstrates that a low-cost substrate can produce bacterial PHB with thermal and thermodynamic properties of interest for the processing, enhancing its potential applications.

The kinetic behavior and combustion characteristics of orange-tree pruning, olive-tree pruning, almond shell, pistachio shell, and pine-tree pruning, were investigated using thermogravimetric analysis (TGA) under inert and oxidative atmospheres at heating rates of 5–20 °C/min. The study combined model-free kinetic methods (Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, and Friedman) with the Coats–Redfern reaction model to elucidate kinetic parameters and reaction mechanisms. Distinct thermal decomposition stages were observed, corresponding to the sequential degradation of hemicellulose, cellulose and lignin. The differences in the profiles were strongly linked to the lignocellulosic composition of the materials. Almond and pistachio shells, with higher hemicellulose contents, exhibited earlier devolatilization and marked peak of hemicellulose, while pine and orange and olive-tree pruning showed single, well-defined peaks around 320–380 °C, reflecting the dominant decomposition of crystalline cellulose. The ignition and burnout temperatures of the selected materials were analyzed by using referencing methods, showing variations depending on the biomass type, heating rate and method used, with pistachio and almond shells demonstrating higher burnout temperatures compared to the other materials. Then, model-free methods (Flynn–Wall–Ozawa FWO, Kissinger–Akahira–Sunose KAS and Friedman FR) were used to determine activation energies, while the Coats-Redfern method provided insights into the reaction mechanism. In pyrolysis, activation energies (E_a) increased with the conversion level (α), indicating a dependency on the decomposition stage; for example, for orange-tree pruning, E_a rose from 77.88 kJ mol⁻¹ at α = 0.1 to 246.58 kJ mol⁻¹ at α = 0.9 (FWO). The application of the Coats-Redfern method reveals distinct reaction mechanisms across biomass components, with diffusional models (D-series) providing the best fit for moisture removal and hemicellulose decomposition, while F-series models effectively capture the complexity of cellulose and lignin degradation.

Four key parameters—culture depth, paddle wheel speed, paddle wheel position, and the number of baffles in the field-scale raceway pond (FSRP) — were first optimized experimentally and then validated by CFD (computational fluid dynamics) to increase the potential of the microalga Chlorella sp. for biodiesel applications. An experimental optimization using the following ideal parameters produced the highest yield of 1.89 g/L of Chlorella sp. biomass: one baffle condition, paddle speed (60 rpm), culture depth (20 cm), and paddle position (2 o’clock). Similarly, the lipid content of Chlorella sp. varied between 17 and 18% in all conditions examined, but it was slightly higher at 18.95% in the no-stirring condition. According to CFD models, an ideal culture depth of 20–25 cm yields a streamlined velocity profile and reduced turbulence, while paddle wheel speeds between 50 and 60 rpm significantly enhance mixing. The paddlewheel positions at 2 and 8 o’clock provided similar hydrodynamic advantages by ensuring a steady velocity profile and lessening turbulence-induced stress on algal cells. The one- or two-baffle design is recommended for large-scale applications because it offers the best nutrient distribution and mixing without appreciably raising energy consumption. The optimal FSRP settings found through experimentation were well-validated by the CFD simulations. The fatty acid profile of the biodiesel from the CFD-optimized FSRP condition consisted mainly of 32.65% palmitic and 13.48% oleic acid. Eventually, the fuel properties of Chlorella sp. biodiesel from the CFD-optimized FSRP condition meet the ASTM and European biodiesel standards.

The goal of the current study was to convert bioenergy from extracts of Chlorella marina, Sargassum muticum, Kappaphycus alvarezii and Ulva Lactuca (direct culture) to enrich rotifer Brachionus angularis, which was then fed to larvae of Asian seabass (Lates calcarifer). The larvae with an initial mean length of 4.1 ± 0.6 mm and weight of 0.40 ± 0.5 mg, were reared and fed with algal extracts-enriched rotifers for 15 days. Among tested treatments, rotifers enriched with S. muticum biomass consistently outperformed than other diets. Seabass larvae receiving S. muticum-enriched rotifers exhibited significantly higher final mean body weight (30.3 ± 5.2 mg), total length (12.5 ± 1.8 mm), specific growth rate (31.0 ± 0.2% day⁻¹), and weight gain (29.92 ± 2.7%) compared to other tested diets. S. muticum’s fatty acid composition showed a maximal concentration of 26.936 ± 0.07% arachidonic acid and 18.143 ± 1.1% eicosapentaenoic acid. 43.3 ± 0.1% oleic acid (C18:1n-9), 36.2 ± 0.2% palmitic acid (C16:0), 9.2 ± 0.2% docosahexaenoic acid (C22:6n-3), and 8.7 ± 0.7% palmitoleic acid (C16:1) were found in rotifers fed a diet including S. muticum. The contents of 30.3 ± 0.3% docosahexaenoic acid (C22:6n-3), 20.6 ± 0.5% oleic acid (C18:1n-9), and 19.9 ± 0.7% palmitic acid (C16:0) in 2-dph seabass larvae fed S. muticum-enriched rotifers were considerably greater (p < 0.05) than those at 13 dph. The DHA content of 13 dph larvae fed a S. muticum diet was significantly higher (p < 0.05) than C. marina. Lastly, rotifers enriched C. marina and S. muticum fed to 13 dph larvae fatty acids were considerably higher (p> 0.05) than those fed to 2 dph larvae. Furthermore, S. muticum enrichment had a significant positive influence on larvae nutritional composition and fatty acid profile. Observed results indicates S. muticum extracts served a suitable dietary source for rotifer enrichment, thus enhanced the nutritional quality of live feed. Therefore, S. muticum extract can be considered a promising alternative for rotifer culture and nutritional enhancement in fish larvae rearing to scale up large level.

Co-pyrolysis of biomass and plastic waste has been identified as a promising strategy for producing higher yields of biochar, bio-oil, and syngas compared to using single feedstocks. However, significant gaps and challenges remain, and further research is still required to improve efficiency of these processes. In this paper Aspen Plus V12^® was used to simulate H₂, CO, CO₂, and CH₄ production from the co-pyrolysis of date seeds and tire plastic waste. The flowsheet of the simulation model was composed of a dryer, a water separator, a pyrolizer, a cooler, and a separator. The results were further modelled utilizing the software Design Expert 12 utilizing the explanatory factors temperature (300–500 °C), mixing ratio (0%, 50%, and 100%, where 0% represents only date seeds, 50% represents a 50:50 mixture of tire plastic and date seeds, and 100% represents only tire plastic), and pressure (1 bar, 3 bar, and 5 bar) and four response variables (H₂, CO, CO₂, and CH₄). The main results obtained in this study show that co-pyrolysis of date seeds and tire plastic waste is more beneficial for CO₂ (333 kg/hr), and CH₄ (283 kg/hr) production, than for CO (27 kg/hr) and H₂ (15 kg/hr). The highest amount of H₂, CO, and CO₂ were obtained at a reaction temperature of 500 °C, pressure of 1 bar, and blending ratio of 100%, while the highest amount of CH₄ was obtained at a reaction temperature of 300 °C, pressure of 1 bar, and blending ratio of 0%. These results suggest that it is possible to use co-pyrolysis as a suitable strategy to valorize date seeds and tire plastic waste and produce value-added products, such as CO₂, and CH₄ that can be used as alternative renewable sources of energy for the transportation, heating, cooling, and electricity sectors.

Cellulase production by Trichoderma reesei using bamboo as a solid substrate has not been previously investigated. Thus, the suitability of bamboo as a cellulase production medium in solid-state fermentation was evaluated using T. reesei ATCC56765 (RUT-C30) in this study. On day 7, the cellulase activity (1.9 filter paper unit activity (FPU)/g) with dry bamboo as the medium was lower than that obtained using wheat straw and rice straw solid media. Cellulase activity increased to 3.6 FPU/g in a dry bamboo-wheat bran mixed medium (BWM) at a weight ratio of 1:1 on day 10. Analysis at cultivation temperatures (26 °C, 22 °C, and 18 °C) lower than the optimal temperature (30 °C) revealed the highest cellulase activities of 4.0 and 6.7 FPU/g-dry medium at 22 °C in bamboo and BWM, respectively. Furthermore, the highest β-glucosidase activity of 49.3 U/g-medium was achieved at 22 °C in BWM, which was 13.3-fold higher than that obtained in bamboo medium at 30 °C. Finally, the cellulases produced from the bamboo and BWM media could successfully hydrolyze alkali-treated rice straw and produce ethanol via simultaneous saccharification and fermentation. In conclusion, bamboo represents a suitable medium for cellulase production, and a temperature of 22 °C enhances cellulase production with increased β-glucosidase activity.

Tannery solid waste management posed significant environmental challenges, particularly due to the high organic load and potential toxicity of untreated fleshings. This study explored the Anaerobic co-digestion (AcoD) of chromium-free tannery fleshing, cow dung, and sewage to optimize biogas production under varying operational conditions. A multi-phase experiment was adopted, initially comparing room and controlled temperature conditions, followed by evaluations across mesophilic to lower thermophilic ranges (30–45 °C) and nine different substrate mix ratios. The highest methane yield and digestion performance were achieved at 45 °C with a substrate including a mix of fleshing, sewage, and cow dung as 1:2:1. Process parameters, primarily pH, COD reduction, volatile solid (VS) reduction, and volatile fatty acids-to-alkalinity ratio, were monitored to assess system stability. A Bayesian Network was constructed to model interdependencies among these variables, identifying temperature, initial volatile solids, and substrate-to-inoculum (S/I) ratio as key drivers of gas production. A sensitivity analysis based on mutual information and belief variance further highlighted their influence, providing a probabilistic framework for process optimization with strong interdependence, such as S/I ratio-pH (75.0%), S/I ratio-initial VS (61.5%), and VFA/Alkalinity ratio-temperature (61.6%). Thereafter, a Central Composite Design coupled with desirability analysis was used to identify optimal operational settings, followed by validation experiments, resulting only 5.6 ± 0.5% error. This study demonstrated a successful integration of experimental results and probabilistic modeling to enhance energy recovery from hazardous tannery waste, and its findings contributed to the sustainable waste-to-energy strategy as well as the circular bioeconomy.