Search Results (3,493)

The production of orange (Citrus sinensis) generates many residues, and the few that are used are usually by-products of the fruit juice processing industry. Among the residues, wood is potentially advantageous for use in bioenergy, but with few records in the literature. In this sense, this study sought to evaluate the feasibility of using orange wood for energy purposes by performing chemical characterization, immediate analysis, FTIR, calorific value, thermogravimetry and bulk and energetic densities for three compositions: 100% trunk (100T), 90% trunk + 10% bark (90T10B) and 100% bark (100B). 100T showed a higher fixed carbon content (16.76%) and equality with 90T10B in lignin, holocellulose, useful calorific value and volatile materials. 100B presented higher extractives and ash contents of 19.67% and 10.35%, respectively. The FTIR spectra and thermogravimetric curves were similar in 100T and 90T10B. 100B showed more stages of degradation and a higher incidence of peaks in the range 780–612 cm⁻¹. The bulk density was equal in 100T and 90T10B, but the energy density was higher in 100T (6.16 Gj.m⁻³). 100T and 90T10B are good options for bioenergy and the chemical composition and thermal degradation of 100B point to new investigations in this composition. Full article

The European Union, in pursuit of the goal of reducing emissions by at least 55% by 2030 and achieving climate neutrality by 2050, is deploying different actions, with industry decarbonization as a key strategy. However, increasing electricity demand requires an intensification of energy generation from clean technologies, and the energy system’s expansion is hindered by renewable generation’s climatic dependencies and the imperative for substantial electrical infrastructure investments. Although the transmission grid is expected to grow, flexibility mechanisms and innovative technologies need to be applied to avoid an overwhelming growth. In this context, this paper presents a thorough assessment, conducted within the FLEXINDUSTRIES project, of the flexibility potential across seven energy-intensive industries (automotive industry, biofuel production, polymer manufacturing, steel manufacturing, paper mills, pharmaceutical industry, and cement production). The methodology followed during the analysis entails reviewing the state-of-the-art existing flexibility mechanisms, industries’ energy markets engagement, and technical/operational readiness. The results highlight the feasibility of the proposed actions for enabling energy market flexibility through demand-response programs, quantifying energy opportunities, and pinpointing regulatory and technical barriers. Full article

Nannochloropsis gaditana, a microalga known for its photosynthetic efficiency, serves as a cell factory, producing valuable biomolecules such as proteins, lipids, and pigments. These components make it an ideal candidate for biofuel production and pharmaceutical applications. In this study, we genetically engineered N. gaditana to overexpress the enzyme fructose-1,6-bisphosphatase (cyFBPase) using the Hsp promoter, aiming to enhance sugar metabolism and biomass accumulation. The modified algal strain, termed NgFBP, exhibited a 1.34-fold increase in cyFBPase activity under photoautotrophic conditions. This modification led to a doubling of biomass production and an increase in eicosapentaenoic acid (EPA) content in fatty acids to 20.78–23.08%. Additionally, the genetic alteration activated the pathways related to glycine, protoporphyrin, thioglucosides, pantothenic acid, CoA, and glycerophospholipids. This shift in carbon allocation towards chloroplast development significantly enhanced photosynthesis and growth. The outcomes of this study not only improve our understanding of photosynthesis and carbon allocation in N. gaditana but also suggest new biotechnological methods to optimize biomass yield and compound production in microalgae. Full article

This study examines the pyrolysis of agricultural residues, namely, coconut shells, rice husks, and cattle manure, in a vertical fixed-bed reactor at varying temperatures from 300 to 800 degrees Celsius for biochar production. The research aimed to evaluate the potential of biochar as biofuels, adsorbents, and soil amendments. Proximate, ultimate, and elemental analyses were conducted to determine their composition and caloric values. Several analytical techniques were used in the physical and chemical characterization of the biochar (SEM, FTIR, BET). The results indicated that the highest S_BET values were achieved under different conditions for each biochar: 89.58 m²/g for BC-CS-700, 202.39 m²/g for BC-RH-600, and 42.45 m²/g for BC-CD-800. Additionally, all three biochars exhibited the highest caloric values at 600 °C. The results showed that 600 °C is the general optimal temperature to produce biochar from an assortment of biomass materials, considering their use for a variety of purposes. BC-CS-800 had the highest elemental carbon content at 93%, accompanied by a relative decrease in oxygen content. The van Krevelen diagram of biochar products shows that biochars derived from coconut shells and rice husks are suitable for use as fuels. Furthermore, FTIR analysis revealed the presence of oxygen-containing functional groups on the biochar surface, enhancing their pollutant adsorption capabilities. This study provides valuable insights into the scalable and environmentally sustainable production of biochar, emphasizing its role in improving soil quality, increasing energy density, and supporting sustainable agricultural practices. Full article

Waste glycerol can be subjected to various processing operations, including purification and refining, to obtain glycerol of an appropriate purity. Alternative methods for utilising waste glycerol are also being sought, e.g., by converting it into other valuable chemical products or biofuels. Therefore, various technologies are being developed to ensure effective and sustainable utilisation of this type of waste. The production of value-added products from waste glycerol strongly determines the improvement of the economic viability of biofuel production and corresponds to the model of a waste-free and emission-free circular economy. This paper characterises the mechanisms and evaluates the efficiency of existing methods for microbiological utilisation of waste glycerol into liquid biofuels, including biodiesel, bioethanol and biobutanol, and identifies further production avenues of value-added products. In addition, it presents the results of a bibliographical analysis of publications related to the production of liquid fuels and economically valuable products from glycerol, assesses the progress of research and application work and, finally, identifies areas for future research. Full article

This study focuses on optimizing the medium composition for cellular biomass production and bioconversion of ethylene glycol (EG) to glycolic acid (GA) using Gluconobacter oxydans CCT 0552. The improvement in cellular growth in the presence of yeast extract and peptone led to a 35.7% and 32.7% increase, respectively, compared to the medium with each of these carbon sources separately. Negligible growth was produced when (NH₄)₂SO₄ and urea were used. Optimal bioconversion results were very similar for both the stirred tank and bubble column bioreactors, with GA concentrations reaching 49.4 g/L and 47.7 g/L, volumetric productivities of 0.35 g/L∙h and 0.33 g/L∙h, and product yield factors of 1.08 g/g and 0.94 g/g, respectively. An extended fed-batch strategy using a STR-type bioreactor achieved a concentration of glycolic acid of 94.2 g/L, corresponding to a volumetric productivity of 0.41 g/L∙h and a yield factor of 1.19 g/g. The resulting efficiency of this biological transformation process achieved a remarkable value of 97.3%, simultaneously with a significant decrease in the substrate amount by 90.5%. This study demonstrates the efficiency of G. oxydans in producing GA, offering a cost-effective and environmentally sustainable production method. Full article

Low-Speed Pre-Ignition (LSPI) is a destructive combustion event associated primarily with new, ultra-efficient, downsized gasoline engines, which provide efficiency benefits in general operation. Biofuels, specifically bio-gasoline, are an alternative fuel that attempts to reduce the harmful emissions output by modern Internal Combustion Engines (ICEs). This study attempts to understand the effect of biofuel use on LSPI, through the use of a numerical simulation tool developed in Ricardo Wave. Development of the tool includes the integration of RFlame, an extension capable of modeling autoignition within a 1D domain. Use of the tool highlights the impact of five ethanol blends, E10, E20, E30, E50 and E85, with clear impacts on both the severity and frequency of LSPI events correlated with chemical properties, such as the enthalpy of vaporization (HoV) and octane number. E30 is highlighted as the critical blend for LSPI severity, with both increased severity and intensity seen with a 30% concentration, and a greater sensitivity to effects such as the start of ignition (SOI). Higher-concentration biofuels, such as E50 and E85 bio-gasoline, show much more favorable behaviors, such as a vast reduction in end-gas knock events, but are limited in their use due to their deployment being both cost-prohibitive and potentially damaging in current hardware. Future work on this topic will surround the further development of the simulation tool to integrate 3D solving elements, understand the role of fluid interactions in LSPI, and study optimal fuel characteristics for future use in ICEs. Full article

The presented case study evaluates the environmental and economic effects of carbon bio pellet production from orchard grass by Farmutil HS Inc. through the hydrothermal carbonisation method, using obtained biofuel as a substitute for natural gas for heat production. Hydrothermal carbonisation is a zero-waste technology that produces renewable bioenergy by substituting fossil fuels for non-renewable resources. Processing 60,000 t/y of orchard grass with this method resulted in a total amount of heat production of 456,780 GJ/y. This means that over 60% of the energy produced from natural gas could be substituted by renewable bioenergy. It is also very important that the estimated cost of heat produced from carbon bio pellets is 29% lower in comparison to the cost of heat produced from natural gas Full article

Microbial fuel cells (MFCs) are sustainable energy recovery systems because they use organic waste as biofuel. Using critical raw materials (CRMs), like platinum-group metals, at the cathode side threatens MFC technology’s sustainability and raises costs. By developing an efficient electrode design for MFC performance enhancement, CRM-based cathodic catalysts should be replaced with CRM-free materials. This work proposes developing and optimizing iron-based air cathodes for enhancing oxygen reduction in MFCs. By subjecting iron phthalocyanine and carbon black pearls to controlled thermal treatments, we obtained Fe-based electrocatalysts combining high surface area (628 m² g⁻¹) and catalytic activity for O₂ reduction at near-neutral pH. The electrocatalysts were integrated on carbon cloth and carbon paper to obtain gas diffusion electrodes whose architecture was optimized to maximize MFC performance. Excellent cell performance was achieved with the carbon-paper-based cathode modified with the Fe-based electrocatalysts (maximum power density-PD_max = 1028 mWm⁻²) compared to a traditional electrode design based on carbon cloth (619 mWm⁻²), indicating the optimized cathodes as promising electrodes for energy recovery in an MFC application. Full article

Hydrolases are the most popular enzymes, and among the most valuable in biotechnological applications. Some hydrolases, such as lipases, esterases, proteases, cellulases and amylases, are used in the food industry and the production of biopharmaceuticals, biofuels, biopolymers and detergents. Of special interest are those obtained from thermophilic microorganisms. Although there is great microbial diversity in extreme environments, the investigations aimed at detecting and isolating enzymes with potential for polyester degradation such as polyethylene terephthalate (PET) are limited. In this work, we explored the metagenomic library of an oil-enriched soil sample from the “Los Humeros” geothermal field by means of in silico probes in search for enzymes potentially able to degrade polyesters. Using conserved motifs and activity-relevant sites of reported polyester hydrolases, we designed probes that allowed us to identify 6 potential polyester hydrolases in the metagenome. Three-dimensional structure prediction revealed a canonical α/β fold and a cap covering the active site of the enzymes. The catalytic triads were composed of Ser, His and Asp. Structural comparison, substrate binding site analysis and molecular docking suggested their potential as polyester hydrolases, particularly cutinases and PETases. An enzyme, REC98271, was cloned, expressed and characterized, showing thermophilic properties and preference for short-chain substrates. These findings contribute to our understanding of enzyme diversity in “Los Humeros” metagenome and their potential applications in biodegradation and recycling processes. Full article

This study analyzes the combustion of pellets and briquettes made of plant biomass in low-power heating devices powered periodically with fuel being placed on the grate, as well as after modification using an automatic fuel feeding system in the gutter burner. The use of herbaceous biomass in the form of pellets in low-power heating devices with automatic fuel feeding and combustion in a gutter burner is not widely promoted and popular. Therefore, this study used four types of herbaceous waste biomass (wheat straw, rye straw, oat straw and hay) and one type of woody waste biomass (birch sawdust) for testing. The basic chemical characteristics were determined for the raw materials. After appropriate preparation, the selected starting materials were subjected to briquetting and pelleting processes. Selected physical properties were also determined for the obtained biofuels. Biofuels made from birch sawdust had the lowest heat value (16.34 MJ·kg⁻¹), although biofuels made from wheat, rye and hay straw had a slightly lower calorific value, respectively: 16.29; 16.28 and 16.26 MJ·kg⁻¹. However, the calorific value of oat straw biofuels was only 15.47 MJ kg⁻¹. Moreover, the ash content for herbaceous biomass was 2–4 times higher than for woody biomass. Similar differences between herbaceous and woody biomass were also observed for the nitrogen and sulfur content. To burn the prepared biofuels, a domestic grate-fired biomass boiler was used, periodically fed with portions of fuel in the form of pellets or briquettes (type A tests), which was then modified with a gutter burner enabling the automatic feeding of fuel in the form of pellets (type B tests). During the combustion tests with simultaneous timing, the concentration of CO₂, CO, NO and SO₂ in the exhaust gases was examined and the temperature of the supplied air and exhaust gases was measured. The stack loss (qA), combustion efficiency index (CEI) and toxicity index (TI) were also calculated. The research shows that the use of automatic fuel feeding stabilizes the combustion process. The combustion process is balanced between herbaceous and woody biomass biofuels. Disparities in CO₂, CO and T_gas emissions are decreasing. However, during type B tests, an increase in NO emissions is observed. At the same time, the research conducted indicates that the combustion of herbaceous biomass pellets with their automatic feeding into the combustion chamber is characterized by an increase in combustion efficiency, indicating that when the combustion process is automated, they are a good replacement for wood biofuels—both pellets and briquettes. Full article

Heavy metal pollution is a gradually growing environmental issue that hinders the growth and development of plants, and also destabilizes soil. Consequently, eco-friendly phytoremediation methods have gained traction, with energy crops emerging as a particularly effective solution. Energy crops not only provide high-quality plant materials for detoxification and remediation of heavy metal pollution, but also possess energy properties conducive to biofuel production. Therefore, this paper delves into the tolerance mechanism of energy crops towards heavy metal toxicity, elucidating processes such as root complex-mediated inhibition of metal migration and response to reactive oxygen species (ROS) through heavy metal-related proteins, enzyme systems, reactive nitrogen species (RNS), and hormones. Moreover, it summarizes the heavy metals remediation mechanisms of energy crops, including uptake, translocation, chelation, immobilization, and sequestration. This paper explores applications of energy crops in heavy metal pollution remediation, emphasizing the methods for efficient biochar remediation and biofuel generation. Furthermore, potential challenges in using energy crops for heavy metal pollution remediation are outlined. By systematically examining the function mechanisms and prospective applications of energy crops in heavy metal pollution bioremediation, this paper serves as a valuable reference for both research and practical implementation in this field. Full article

Biorefinery plays a crucial role in the decarbonization of the current economic model, but its high investments and costs make its products less competitive. Identifying the best technological route to maximize operational synergies is crucial for its viability. This study presents a new superstructure model based on mixed integer linear programming to identify an ideal biorefinery configuration. The proposed formulation considers the selection and process scale adjustment, utility selection, and heat integration by heat cascade integration from different processes. The formulation is tested by a study where the impact of new technologies on energy efficiency and the total annualized cost of a sugarcane biorefinery is evaluated. As a result, the energy efficiency of biorefinery increased from 50.25% to 74.5% with methanol production through bagasse gasification, mainly due to its high heat availability that can be transferred to the distillery, which made it possible to shift the bagasse flow from the cogeneration to gasification process. Additionally, the production of DME yields outcomes comparable to methanol production. However, CO₂ hydrogenation negatively impacts profitability and energy efficiency due to the significant consumption and electricity cost. Nonetheless, it is advantageous for surface power density as it increases biofuel production without expanding the biomass area. Full article

Microbial biofilms present one of the most widespread forms of life on Earth. The formation of microbial communities on various surfaces presents a major challenge in a variety of fields, including medicine, the food industry, shipping, etc. At the same time, this process can also be used for the benefit of humans—in bioremediation, wastewater treatment, and various biotechnological processes. The main direction of using electroactive microbial biofilms is their incorporation into the composition of biosensor and biofuel cells This review examines the fundamental knowledge acquired about the structure and formation of biofilms, the properties they have when used in bioelectrochemical devices, and the characteristics of the formation of these structures on different surfaces. Special attention is given to the potential of applying the latest advances in genetic engineering in order to improve the performance of microbial biofilm-based devices and to regulate the processes that take place within them. Finally, we highlight possible ways of dealing with the drawbacks of using biofilms in the creation of highly efficient biosensors and biofuel cells. Full article

In the current context of fossil energy depletion and the requirement for low carbon emissions, the efficient use of energy and a diversified energy mix have become increasingly important. The use of cleaner and low-carbon alternative fuels is rapidly growing. However, corrosion remains a key issue limiting the large-scale application of alternative fuels. This paper describes the corrosion characteristics of different alternative fuels. Also, the mechanisms of fuel corrosion, corrosion measurement methods, and the future of corrosion inhibitor applications are discussed. Corrosion causes changes in material weight and surface morphology and generates electrical signals as it progresses. Although there are well-established methods to characterize corrosion by recognizing these changes, there is still a need to identify a universal standard signal for their detailed description. For the foreseeable future, corrosion in fuels will continue to be mitigated by the addition of corrosion inhibitors. The research on corrosion inhibitors focuses on green corrosion inhibitors and multifunctional corrosion inhibitors. However, further analysis is needed to understand the active ingredients in green corrosion inhibitors, and the mechanism of corrosion inhibition for different types of corrosion inhibitors needs further research. Full article