Search Results (62)

Microbial decomposition of persistent natural compounds such as phenolic lignin and polysaccharides in plant cell walls plays a crucial role in the global carbon cycle and underpins diverse biotechnological applications. Among microbial decomposers, fungi from the Ascomycota and Basidiomycota phyla have evolved specialized mechanisms for efficient lignocellulosic biomass degradation, employing extracellular enzymes and synergistic fungal consortia. Fungal coculture, defined as the controlled, axenic cultivation of multiple fungal species or strains in a single culture medium, is a promising strategy for industrial processes. This approach to biomass conversion offers potential for enhancing production of enzymes, biofuels, and other high-value bioproducts, while enabling investigation of ecological dynamics and metabolic pathways relevant to biorefinery operations. Lignocellulosic biomass conversion into fuels, energy, and biochemicals is central to the bioeconomy, integrating advanced biotechnology with sustainable resource use. Recent advancements in -omics technologies, including genomics, transcriptomics, and proteomics, have facilitated detailed analysis of fungal metabolism, uncovering novel secondary metabolites and enzymatic pathways activated under specific growth conditions. This review highlights the potential of fungal coculture systems to advance sustainable biomass conversion in alignment with circular bioeconomy goals. Full article

The xeno-fungusphere, a novel microbial ecosystem formed by integrating exogenous fungi, indigenous soil microbiota, and electroactive microorganisms within microbial fuel cells (MFCs), offers a transformative approach for agricultural remediation and medicinal plant conservation. By leveraging fungal enzymatic versatility (e.g., laccases, cytochrome P450s) and conductive hyphae, this system achieves dual benefits. First, it enables efficient degradation of recalcitrant agrochemicals, such as haloxyfop-P, with a removal efficiency of 97.9% (vs. 72.4% by fungi alone) and a 27.6% reduction in activation energy. This is driven by a bioelectric field (0.2–0.5 V/cm), which enhances enzymatic activity and accelerates electron transfer. Second, it generates bioelectricity, up to 9.3 μW/cm², demonstrating real-world applicability. In medicinal plant soils, xeno-fungusphere MFCs restore soil health by stabilizing the pH, enriching dehydrogenase activity, and promoting nutrient cycling, thereby mitigating agrochemical-induced inhibition of secondary metabolite synthesis (e.g., ginsenosides, taxol). Field trials show 97.9% herbicide removal in 60 days, outperforming conventional methods. Innovations, such as adaptive electrodes, engineered strains, and phytoremediation-integrated systems, have been used to address soil and fungal limitations. This technology bridges sustainable agriculture and bioenergy recovery, offering the dual benefits of soil detoxification and enhanced crop quality. Future IoT-enabled monitoring and circular economy integration promise scalable, precision-based applications for global agroecological resilience. Full article

The rapid increase in agricultural waste in recent years has led to significant losses and challenges for agro-industrial companies. At the same time, the growing demand for energy to support daily human activities has prompted these companies to seek new and sustainable methods for generating electric energy, which is crucial. Sucrose extracted from fruit waste can act as a carbon source for microbial fuel cells (MFCs), as bacteria metabolize sucrose to generate electrons, producing electric current. This research aims to evaluate the potential of sucrose as an additive to enhance the use of asparagus waste as fuel in single-chamber MFCs. The samples were obtained from CUC SAC in Trujillo, Peru. This study utilized MFCs with varying sucrose concentrations: 0% (Target), 5%, 10%, and 15%. It was observed that the MFCs with 15% sucrose and 0% sucrose (Target) produced the highest electric current (5.532 mA and 3.525 mA, respectively) and voltage (1.729 V and 1.034 V) on the eighth day of operation, both operating at slightly acidic pH levels. The MFC with 15% sucrose exhibited an oxidation-reduction potential of 3.525 mA, an electrical conductivity of 294.027 mS/cm, and a reduced chemical oxygen demand of 83.14%. Additionally, the MFC-15% demonstrated the lowest internal resistance (128.749 ± 12.541 Ω) with a power density of 20.196 mW/cm² and a current density of 5.574 A/cm². Moreover, the microbial fuel cells with different sucrose concentrations were connected in series, achieving a combined voltage of 4.56 V, showcasing their capacity to generate bioelectricity. This process effectively converts plant waste into electrical energy, reducing reliance on fossil fuels, and mitigating methane emissions from the traditional anaerobic decomposition of such waste. Full article

The field of bio-nanotechnology has seen significant advancements in recent years, particularly in the synthesis and application of bio-nanoparticles (BNPs). This review focuses on the green synthesis of BNPs using biological entities such as plants, bacteria, fungi, and algae. The utilization of these organisms for nanoparticle synthesis offers an eco-friendly and sustainable alternative to conventional chemical and physical methods, which often involve toxic reagents and high energy consumption. Phytochemicals present in plant extracts, unique metabolic pathways, and biomolecules in bacteria and fungi, and the rich biochemical composition of algae facilitate the production of nanoparticles with diverse shapes and sizes. This review further explores the wide-ranging applications of BNPs in various fields like therapeutics, fuel cells, energy generation, and wastewater treatment. In therapeutics, BNPs have shown efficacy in antimicrobial, anti-inflammatory, antioxidant, and anticancer activities. In the energy sector, BNPs are being integrated into fuel cells and other energy generation systems like bio-diesel to improve efficiency and sustainability. Their catalytic properties and large surface area enhance the performance of these devices. Wastewater treatment is another critical area where BNPs are employed for the removal of heavy metals, organic pollutants, and microbial contaminants, offering a cost-effective and environmentally friendly solution to water purification. This comprehensive review highlights the potential of bio-nanoparticles synthesized through green methods. It highlights the need for further research to optimize synthesis processes, understand mechanisms of action, and expand the scope of their applications. BNPs can be utilized to address advantages and some of the pressing challenges in medicine, energy, and environmental sustainability, paving the way for innovative and sustainable technological advancements in future prospects. Full article

Microalgal biomass contributes to the valorization of urban and agro-industrial solid waste via hydrothermal co-liquefaction (co-HTL) for the production of biocrude, a sustainable substitute for petroleum. Tropical and populous countries like Brazil generate a lot of agro-industrial waste, such as sugarcane bagasse and malt bagasse, as well as sludge from sewage treatment plants. Such residues are potential sources of biocrude production via thermochemical conversion. To increase biocrude productivity, microalgal biomass has been successfully used in mixing the co-HTL process feed with different residues. In addition to biocrude, co-HTL generates an aqueous phase that can be used to produce H₂ and/or electricity via microbial energy cells. In this sense, this paper aims to present the potential for generating energy from solid waste commonly generated in emerging countries such as Brazil based on a simplified scheme of a conceptual biorefinery employing algal biomass co-HTL together with sugarcane bagasse, malt bagasse, and sludge. The biorefinery model could be integrated into an ethanol production plant, a brewery, or a sewage treatment plant, aiming at the production of biocrude and H₂ and/or electricity by bioelectrochemical systems, such as microbial electrolysis cells and microbial fuel cells. Full article

In a plant microbial fuel cell (P-MFC), the plant provides the fuel in the form of exudates secreted by the roots, which are oxidised by electroactive bacteria. The immature plant is hampered by low energy yields. Several factors may explain this situation, including the low open-circuit voltage of the plant cell. This is a function of the development of the biofilm formed by the electroactive bacteria on the surface of the anode, in relation to the availability of the exudates produced by the roots. In order to exploit the fertilising role of biochars, a plant cell was developed from C. citratus and grown in a medium to which 5% by mass of coconut shell biochar had been added. Its effect was studied as well as the distance between the electrodes. The potential of Cymbopogon citratus was also evaluated. Three samples without biochar, with inter-electrode distances of 2, 5 and 7 cm, respectively, identified as SCS2, SCS5 and SCS7, and three with the addition of 5 % biochar, with the same inter-electrode distance values, identified as S2, S5 and S7, were prepared. Open-circuit voltage (OCV) measurements were taken at 6 a.m., 1 p.m. and 8 p.m. The results showed that all the samples had high open-circuit voltage values at 1 p.m. Samples containing 5% biochar had open-circuit voltages increased by 16 %, 8.94% and 5.78%, respectively, for inter-electrode distances of 2, 5 and 7 cm compared with those containing no biochar. Furthermore, the highest open-circuit voltage values were obtained for all samples with C. citratus at an inter-electrode distance of 5 cm. The maximum power output of the PMFC with C. citratus in this study was 75.8 mW/m², which is much higher than the power output of PMFCs in recent studies. Full article

Although soil is mainly perceived as the basic component of agricultural production, it also plays a pivotal role in environmental protection and climate change mitigation. Soil ecosystems are the largest terrestrial carbon source and greenhouse gas emitters, and their degradation as a result of aggressive human activity exacerbates the problem of climate change. Application of microbial fuel cell (MFC) technology to soil-based ecosystems such as sediments, wetlands, farmland, or meadows allows for sustainable management of these environments with energy and environmental benefits. Soil ecosystem-based MFCs enable zero-energy, environmentally friendly soil bioremediation (with efficiencies reaching even 99%), direct clean energy production from various soil-based ecosystems (with power production reaching 334 W/m²), and monitoring of soil quality or wastewater treatment in wetlands (with efficiencies of up to 99%). They are also a new strategy for greenhouse gas, soil salinity, and metal accumulation mitigation. This article reviews the current state of the art in the field of application of MFC technology to various soil-based ecosystems, including soil MFCs, sediment MFCs, plant MFCs, and CW-MFCs (constructed wetlands coupled with MFCs). Full article

Microalgae microbial fuel cells (pMFCs) are distinguished by their ability to combine waste utilization with the simultaneous recovery of energy and valuable materials. The generation of high current density is linked to the efficient electron transfer to the anode via the anodic biofilm and the high photosynthetic activity of the microalgae cultivated in the cathode chamber. This review explores the impact of wastewater type on energy production and wastewater treatment. Additionally, it discusses the challenges related to microalgae growth in the cathode chamber, the necessity of aeration, and the sequestration of carbon dioxide from the anode chamber. The efficiency of microalgae in utilizing nutrients from various types of wastewater is also presented. In conclusion, the comparison between wastewater treatment and energy balance in pMFCs and conventional wastewater treatment plants is provided. On average, MFCs consume only 0.024 kW or 0.076 kWh/kg COD, which is approximately ten times less than the energy used by activated sludge bioprocesses. This demonstrates that MFCs offer highly efficient energy consumption compared to traditional wastewater treatment systems while simultaneously recovering energy through exoelectrogenic, bioelectrochemical processes. Full article

A national energy crisis has emerged in South Africa due to the country’s increasing energy needs in recent years. The reliance on fossil fuels, especially oil and gas, is unsustainable due to scarcity, emissions, and environmental repercussions. Researchers from all over the world have recently concentrated their efforts on finding carbon-free, renewable, and alternative energy sources and have investigated microbiology and biotechnology as a potential remedy. The usage of microbial electrolytic cells (MECs) and microbial fuel cells (MFCs) is one method for resolving the problem. These technologies are evolving as viable options for hydrogen and bioenergy production. The renewable energy technologies initiative in South Africa, which is regarded as a model for other African countries, has developed in the allocation of over 6000 MW of generation capacity to bidders across several technologies, primarily wind and solar. With a total investment value of R33.7 billion, the Eastern Cape’s renewable energy initiatives have created 18,132 jobs, with the province awarded 16 wind farms and one solar energy farm. Utilizing wastewater as a source of energy in MFCs has been recommended as most treatments, such as activated sludge processes and trickling filter plants, require roughly 1322 kWh per million gallons, whereas MFCs only require a small amount of external power to operate. The cost of wastewater treatment using MFCs for an influent flow of 318 m³ h⁻¹ has been estimated to be only 9% (USD 6.4 million) of the total cost of treatment by a conventional wastewater treatment plant (USD 68.2 million). Currently, approximately 500 billion cubic meters of hydrogen (H₂) are generated worldwide each year, exhibiting a growth rate of 10%. This production primarily comes from natural gas (40%), heavy oils and naphtha (30%), coal (18%), electrolysis (4%), and biomass (1%). The hydrogen produced is utilized in the manufacturing of ammonia (49%), the refining of petroleum (37%), the production of methanol (8%), and in a variety of smaller applications (6%). Considering South Africa’s energy issue, this review article examines the production of wastewater and its impacts on society as a critical issue in the global scenario and as a source of green energy. Full article

Constructed wetlands (CWs), serving as an advanced wastewater treatment system, play a vital role in both the emission and sequestration of diverse GHGs. However, there are few papers reviewing and analyzing developments in the field. In this study, bibliometrics were used as an essential tool for identifying and establishing connections among key elements within a discipline, as well as for analyzing the research status and developmental trends of the research fields. CiteSpace 6.3.1 was utilized to conduct an analysis of the references from the Web of Science Core Collection pertaining to GHG emissions from CWs over the period from 1993 to 2023. This study showed the following conclusions. (1) Organic nitrogen conversion produces N₂O, which is eventually transformed into N₂ and released from CWs. Anammox represents an attractive route for nitrogen removal. (2) The CO₂ is the final product of the oxidation of organic matter in the influent of CWs and can be fixed by plant photosynthesis. Anaerobic fermentation and CO₂ reduction produce CH₄. The two are emitted through aerenchyma transport, bubble diffusion, and other forms. (3) In the past 30 years, the number of publications and citation frequency shows an increasing trend. China and the United States published more papers. The top ten authors contributed to 20.607% of the total 1019, and the cooperation between different author groups needs to be strengthened. (4) The emerging burst keywords following 2020 are “microbial fuel cell” and “microbial community”, which highlights the current hotspots in research related to GHG emissions from CWs. (5) There is still a lack of long-term and applied discussion on the role of CWs in promoting GHG emission reduction. The relevant reaction conditions and mechanisms need to be explored and the possible research directions can be genetic regulation and information technology. Full article

This paper aims to comprehensively explore the performance and influencing factors of the constructed wetland–microbial fuel cell (CW-MFC) system when treating brine with different concentrations. The main objective is to determine how different salinity levels affect the operation and treatment efficiency of the CW-MFC system. The research results show that Bruguiera gymnorrhiza exhibits strong salt tolerance and can be used as a wetland plant for the CW-MFC system. The closed-circuit CW-MFC system with planted plants has the best performance, with a chemical oxygen demand (COD) removal rate of 84.8%, a total nitrogen (TN) removal rate of 68.12%, and a chloride ion (Cl⁻) removal rate of 29.96%. The maximum power density is 64.79% higher than that of the system without planted plants. The power generation performance of the system first increases and then decreases with the increase in salinity, while the internal resistance keeps decreasing. When the salinity is 2%, the power generation effect is the best, with an average output voltage of 617.3 ± 25.7 mV and a power density of 45.83 mW/m². The removal rates of COD and TN are inhibited with the increase in salinity, while the removal rate of total phosphorus (TP) is not significantly affected. The microbial community grows well under salt stress, but its structure is different. When the salinity is 1%, the optimal distance between electrodes is 10 cm. Considering the pollutant removal performance, the optimal hydraulic retention time is 3 days, and considering the power generation performance, the optimal hydraulic retention time is 2 days. This research provides important value for improving the performance of the CW-MFC system in treating brine. Full article

The global trend towards sustainable development has included the implementation of renewable energy recovery technologies in municipal wastewater treatment plants (WWTPs). WWTPs are energy-intensive consumers with high operational costs and often are dependent from the electricity supplied by the main grid. In this context, the integration of renewable energy recovery technologies into WWTPs emerges as an environment-friendly strategy that enhances energy efficiency, sustainability and reduces energy operating costs. Renewable energy recovery technologies, such as anaerobic digestion, microbial fuel cells, and sludge gasification, can offer multiple benefits for a WWTP. Anaerobic digestion is the most widely adopted technology due to its efficiency in treating sewage sludge and its ability to generate biogas—a valuable renewable energy source. The use of biogas can offset the energy demands of the wastewater treatment process, potentially leading to energy self-sufficiency for the WWTP and a reduction in reliance from the electricity supply from the main grid. Similarly, microbial fuel cells harness the electrochemical activity of bacteria to produce electricity directly from wastewater, presenting a promising alternative for low-energy processes for sustainable power generation. Gasification of sewage sludge is a promising technology for managing municipal sewage sludge, offering key advantages, especially by generating a renewable energy production (sludge is converted into syngas), which further decreases the sludge volume and operating costs with sludge management, helps to eliminate odour associated with sewage sludge, and effectively destroys the pathogens. Adoption of renewable energy sources in WWTPs can be a great alternative to overcome issues of high operating costs and high dependency of electricity from the main grid, but their successful integration requires addressing challenges such as technological maturity, economic feasibility, and regulatory frameworks. This study aims to comprehensively explore the significance of different renewable energy technologies in municipal WWTPs, including site-specific and non-site-specific sources, evaluating their impact on sustainability, energy efficiency, and overall operational effectiveness. This review also highlights some studies in which different strategies were adopted to generate extra revenue and/or reduce operating costs. Through a comprehensive review of current practices and emerging technologies, this study underscores the transformative potential of these innovations in advancing low-emission wastewater management. Full article

Hexavalent chromium (Cr (VI)) and para-chlorophenol (4-CP) are prevalent industrial wastewater contaminants that are recalcitrant to natural degradation and prone to migration in aquatic systems, thereby harming biological health and destabilizing ecosystems. Consequently, their removal is imperative. Compared to conventional chemical treatment methods, CW-MFC technology offers broader application potential. Leersia hexandra Swartz can enhance Cr (VI) and 4-CP absorption, thereby improving wastewater purification and electricity generation in CW-MFC systems. In this study, three CW-MFC reactors were designed with L. hexandra Swartz in distinct configurations, namely, stacked, multistage, and modular, to optimize the removal of Cr (VI) and 4-CP. By evaluating wastewater purification, electrochemical performance, and plant growth, the optimal influent hydraulic retention time (HRT) was determined. The results indicated that the modular configuration at an HRT of 5 days achieved superior removal rates and power generation. The modular configuration also supported the best growth of L. hexandra, with optimal photosynthetic parameters, and physiological and biochemical responses. These results underscore the potential of modular CW-MFC technology for effective detoxification of complex wastewater mixtures while concurrently generating electricity. Further research could significantly advance wastewater treatment and sustainable energy production, addressing water pollution, restoring aquatic ecosystems, and mitigating the hazards posed by Cr (VI) and 4-CP to water and human health. Full article

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that pose significant environmental and health risks. These compounds originate from both natural phenomena, such as volcanic activity and wildfires, and anthropogenic sources, including vehicular emissions, industrial processes, and fossil fuel combustion. Their classification as carcinogenic, mutagenic, and teratogenic substances link them to various cancers and health disorders. PAHs are categorized into low-molecular-weight (LMW) and high-molecular-weight (HMW) groups, with HMW PAHs exhibiting greater resistance to degradation and a tendency to accumulate in sediments and biological tissues. Soil serves as a primary reservoir for PAHs, particularly in areas of high emissions, creating substantial risks through ingestion, dermal contact, and inhalation. Coastal and aquatic ecosystems are especially vulnerable due to concentrated human activities, with PAH persistence disrupting microbial communities, inhibiting plant growth, and altering ecosystem functions, potentially leading to biodiversity loss. In plants, PAH contamination manifests as a form of abiotic stress, inducing oxidative stress, cellular damage, and growth inhibition. Plants respond by activating antioxidant defenses and stress-related pathways. A notable aspect of plant defense mechanisms involves plant-derived extracellular vesicles (PDEVs), which are membrane-bound nanoparticles released by plant cells. These PDEVs play a crucial role in enhancing plant resistance to PAHs by facilitating intercellular communication and coordinating defense responses. The interaction between PAHs and PDEVs, while not fully elucidated, suggests a complex interplay of cellular defense mechanisms. PDEVs may contribute to PAH detoxification through pollutant sequestration or by delivering enzymes capable of PAH degradation. Studying PDEVs provides valuable insights into plant stress resilience mechanisms and offers potential new strategies for mitigating PAH-induced stress in plants and ecosystems. Full article

This paper explores the significant role of Wastewater Treatment Plants (WWTPs) in achieving environmental sustainability, with a particular focus on enhancing energy efficiency, resource recovery, and water reuse. WWTPs are crucial for removing pollutants and recovering resources from wastewater, thereby protecting public health and biodiversity. However, they are also associated with high operational costs, substantial carbon footprints, and energy-intensive processes. This article delves into various strategies and technologies to overcome these challenges, aiming to transform WWTPs from energy consumers to energy-efficient resource recovery hubs. Techniques such as anaerobic digestion and the use of advanced oxidation processes and microbial fuel cells are investigated for their potential in energy recovery and efficiency enhancement. Success stories from around the globe are highlighted to demonstrate the feasibility of transitioning to energy-positive WWTP operations. The integration of water reuse systems is also discussed, highlighting recent advancements that enable treated wastewater to be repurposed for agricultural, industrial, and potable uses, thereby promoting sustainability and water conservation. This paper emphasizes the importance of integrating cutting-edge energy management practices to minimize environmental impacts, reduce operational costs, and contribute to a more sustainable water sector. Full article