Evaluation of bamboo derived biochar as anode catalyst in microbial fuel cell for xylan degradation utilizing microbial co-culture.

This study aimed to examine the microbial degradation of xylan through Bacillus sp. isolated from wastewater. Co-culture of Bacillus licheniformis strain and MTCC-8104 strain of Shewanella putrefaciens were employed in a microbial fuel cell (MFC) to facilitate energy production simultaneous xylan degradation under optimum conditions. Electrochemical properties of MFC and degradation analysis were used to validate xylan degradation throughout various experimental parameters. Degradation of the optimal xylan concentration using co-culture, resulting in a power density of 7.8 W/m3, the anode surface was modified with bamboo-derived biochar in order to increase power density under the same operational condition. Under optimum circumstances, increasing the anode's surface area boosted electron transport and electro-active biofilm growth, resulting in a higher power density of 12.9 W/m3. Co-culture of hydrolyzing and electro-active bacteria was found beneficial for xylan degradation and anode modifications enhance power output while microbial degradation.

Advances in bioelectrochemical systems for bio-products recovery.

Bioelectrochemical systems (BES) have emerged as a sustainable and highly promising technology that has garnered significant attention from researchers worldwide. These systems provide an efficient platform for the removal and recovery of valuable products from wastewater, with minimal or no net energy loss. Among the various types of BES, microbial fuel cells (MFCs) are a notable example, utilizing microbial biocatalytic activities to generate electrical energy through the degradation of organic matter. Other BES variants include microbial desalination cells (MDCs), microbial electrolysis cells (MECs), microbial electrosynthesis cells (MXCs), microbial solar cells (MSCs), and more. BESs have demonstrated remarkable potential in the recovery of diverse products such as hydrogen, methane, volatile fatty acids, precious nutrients, and metals. Recent advancements in scaling up BESs have facilitated a more realistic assessment of their net energy recovery and resource yield in real-world applications. This comprehensive review focuses on the practical applications of BESs, from laboratory-scale developments to their potential for industrial commercialization. Specifically, it highlights successful examples of value-added product recovery achieved through various BES configurations. Additionally, this review critically evaluates the limitations of BESs and provides suggestions to enhance their performance at a larger scale, enabling effective implementation in real-world scenarios. By providing a thorough analysis of the current state of BES technology, this review aims to emphasize the tremendous potential of these systems for sustainable wastewater treatment and resource recovery. It underscores the significance of bridging the gap between laboratory-scale achievements and industrial implementation, paving the way for a more sustainable and resource-efficient future.

Microbial Fuel Cell-Based Biosensors and Applications.

The sustainable development of human society in today's high-tech world depends on some form of eco-friendly energy source because existing technologies cannot keep up with the rapid population expansion and the vast amounts of wastewater that result from human activity. A green technology called a microbial fuel cell (MFC) focuses on using biodegradable trash as a substrate to harness the power of bacteria to produce bioenergy. Production of bioenergy and wastewater treatment are the two main uses of MFC. MFCs have also been used in biosensors, water desalination, polluted soil remediation, and the manufacture of chemicals like methane and formate. MFC-based biosensors have gained a lot of attention in the last few decades due to their straightforward operating principle and long-term viability, with a wide range of applications including bioenergy production, treatment of industrial and domestic wastewater, biological oxygen demand, toxicity detection, microbial activity detection, and air quality monitoring, etc. This review focuses on several MFC types and their functions, including the detection of microbial activity.

Strategic development and performance evaluation of functionalized tea waste ash-clay composite as low-cost, high-performance separator in microbial fuel cell.

The separator is an important component of the microbial fuel cells (MFCs), which separates anode and cathode entities and facilitates ion transfer between both. Despite the high research in separators in recent years, the need for cost-effective, waste-driven selective separators in MFCs persists. Present study discloses the strategic fabrication of functionalized-tea-waste-ash-clay (FTWA-C) composite separator by integrating functionalized tea waste ash (FTWA) with potter's clay. Clay was used as a base, while FTWA was used as cation exchanger. FTWA and clay were separately mixed in four different ratios, 00:100 (C1); 05:95 (C2); 10:90 (C3); 15:85 (C4). Mixtures were then crafted manually as consecutive four layers. C1-side faced anode while separator-cathode-assembly was developed at C4. The separator was characterized by evaluating proton and oxygen transfer coefficient, and water-uptake analysis. The separator was also analysed for elemental composition, microstructure, particle size, and surface area and porous structure. SEM analysis of FTWA showed the presence of 15-100 nm pores. EDS analysis of the FTWA-C showed the presence of hygroscopic oxides, mainly SO42- and SiO2. A slight peak observed at P/Po∼1, confirmed the presence of macropores. The FTWA-C separator showed proton transfer coefficient as high as 18.7 × 10-5 cm/s, and oxygen mass transfer coefficient of 2.1 × 10-4 cm/s. The FTWA-C displayed the highest operating voltage of 612.4.2 mV, the power density of 1.81 W/m3, and COD removal efficiency of 87.52%. The fabrication cost of this separator was estimated to be $9.8/m2. FTWA-C could be an affordable and high-efficiency alternative for expensive ion-exchange membranes in MFCs.

Analysis of pyridine-2-carbaldehyde thiosemicarbazone as an anti-biofouling cathodic agent in microbial fuel cell.

Microbial fuel cells (MFCs) have gained attention due to their applications in the energy and environmental sectors. However, several challenges must be addressed in order to operate MFCs in the real world. Cathode biofouling, which poses mass transfer limitations, is a major factor behind poor performance of MFCs. In this study, a water-insoluble pyridine-2-carbaldehyde thiosemicarbazone (PCT) was synthesized and its efficiency as anti-biofouling agent in the cathode of a multi-criteria MFC (MCMFC) was tested. For the application of PCT, graphite dust and MnO2 nanotubes (NTs) were used as conducting support and oxygen reduction reaction (ORR) catalyst. When the concentration of PCT on the cathode was increased, an increase in the power generation was observed. The PCT loading of 0.05, 0.1, 0.2, and 0.4 mg/cm2 on graphite-MnO2-NTs cathode, resulted in maximum power density of 356.8, 390.93, 418.77, and 434.2 mW/m2, respectively. Half-cell polarization and electrochemical impedance study revealed that the mechanically mixed PCT-MnO2-NTs/graphite dust composite has a higher ORR activity than MnO2-NTs/graphite dust composite, implying that the dispersion of PCT on the cathode surface improves its catalytic activity, possibly due to the antibacterial activity of PCT. PCT played an important role in improved energy recovery and could be applied as an efficient antifouling agent and cathode catalyst for the MFC. KEY POINTS: • Water-insoluble pyridine-2-carbaldehyde thiosemicarbazone (PCT) was synthesized. • A multi-criteria microbial fuel cell (MCMFC) was designed. • PCT was used as an oxygen reduction reaction catalyst in MCMFC.

Development, performance evaluation, and kinetic studies of microbial fuel cell based auto dripping bioelectrochemical reactor (AutoDriBER) for urine treatment.

A bioelectrochemical reactor is an assembly, which facilitates energy generation and resource recovery using electrochemically active microorganisms. To maximise energy production from wastewater in this bioreactor system special design is required. Therefore, in the present study, continuous flow auto dripping bioelectrochemical reactors (AutoDriBERs) were developed as a single and multi-electrode assembly for urine treatment. Further, their performance was assessed by connecting reactors in series and parallel arrangements. AutoDriBER configured in series connection showed the highest 93.64 ± 1.57% chemical oxygen demand removal rate with the 1.38 ± 0.64 V voltage and 2.54 W m-3 polarisation power density. The optimum flow rate for maximum voltage production was tested with various models i.e. the linear, exponential, Sweibull-1, and Sweibull-2 models to confirm voltage prediction and its validity. The Linear and exponential models were found best fitted for voltage production with R2 value of 0.999. These findings infer a novel approach toward optimisation of the complex, inexpensive and self-sufficient design for electricity generation from energy-rich urine wastewater in rural areas.

Integrating Human Waste with Microbial Fuel Cells to Elevate the Production of Bioelectricity.

Due to the continuous depletion of natural resources currently used for electricity generation, it is imperative to develop alternative energy sources. Human waste is nowadays being explored as an efficient source to produce bio-energy. Human waste is renewable and can be used as a source for an uninterrupted energy supply in bioelectricity or biofuel. Annually, human waste such as urine is produced in trillions of liters globally. Hence, utilizing the waste to produce bioenergy is bio-economically suitable and ecologically balanced. Microbial fuel cells (MFCs) play a crucial role in providing an effective mode of bioelectricity production by implementing the role of transducers. MFCs convert organic matter into energy using bio-electro-oxidation of material to produce electricity. Over the years, MFCs have been explored prominently in various fields to find a backup for providing bioenergy and biofuel. MFCs involve the role of exoelectrogens which work as transducers to convert the material into electricity by catalyzing redox reactions. This review paper demonstrates how human waste is useful for producing electricity and how this innovation would be beneficial in the long term, considering the current scenario of increasing demand for the supply of products and shortages of natural resources used to produce biofuel and bioelectricity.

Development of trickling bio-electrochemical reactor (TrickBER) for large scale energy efficient wastewater treatment.

Bioelectrochemical systems such as microbial fuel cells are novel systems; those directly transform the chemical energy contained in organics of wastewater into electrical energy by the metabolic action of the microbial community. During the last two decades, bioelectrochemical systems astonishingly increased their wastewater treatment capabilities, sustainability, and power output. However, studies on scalable architectural designs of bioelectrochemical systems received less attention. Lower power yield and high cost are two major limitations for scaling up of bioelectrochemical systems. This study reports a low cost, scalable, air cathode bio-electrochemical reactor, constructed by adopting a trickling filtration approach (TrickBER) and operated in continuous mode. Various facets of construction, installation, and operation of TrickBER were investigated and optimized to achieve an efficient performance. TrickBER was found suitable in simultaneous electricity generation during continuous wastewater treatment and, in the future, could be used in small/cottage industries.

Fungal-mediated electrochemical system: Prospects, applications and challenges.

Microbial fuel cells (MFCs) that generate bioelectricity from biodegradable waste have received considerable attention from biologists. Fungi play a significant role as both anodic and cathodic catalysts in MFCs. Saccharomyces cerevisiae is a fungus with an ability to transfer electrons through mediators such as methylene blue (MB), neutral red (NR) or even without a mediator. This unique role of fungal cells in exocellular electron transfer (EET) and their interactions with electrodes hold a lot of promise in areas such as wastewater treatment where yeast cell-based MFCs can be used. The present article highlights the physico-chemical factors affecting the performance of fungal-mediated MFCs in terms of power output and degradation of organic pollutants, along with the challenges associated with fungal MFCs. In addition, to this comparative assessment of fungal-mediated bio-electrochemical systems, their development, possible applications and potential challenges are also discussed.

Recent trends in biodegradable polyester nanomaterials for cancer therapy.

Biodegradable polyester nanomaterials-based drug delivery vehicles (DDVs) have been largely used in most of the cancer treatments due to its high biological performance and wider applications. In several previous studies, various biodegradable and biocompatible polyester backbones were used which are poly(lactic acid) (PLA), poly(ε-caprolactone) (PCL), poly(propylene fumarate) (PPF), poly(lactic-co-glycolic acid) (PLGA), poly(propylene carbonate) (PPC), polyhydroxyalkanoates (PHA), and poly(butylene succinate) (PBS). These polyesters were fabricated into therapeutic nanoparticles that carry drug molecules to the target site during the cancer disease treatment. In this review, we elaborately discussed the chemical synthesis of different synthetic polyesters and their use as nanodrug carriers (NCs) in cancer treatment. Further, we highlighted in brief the recent developments of metal-free semi-aromatic polyester nanomaterials along with its role as cancer drug delivery vehicles.

Assessment of expanded polystyrene as a separator in microbial fuel cell.

Separators are considered as an important component in microbial fuel cells (MFCs) to facilitate ion transport and to prevent electrode short circuiting. In the present study, expanded polystyrene (EPS) was evaluated for the first time as a separator in a single-chamber air cathode and dual chamber aqueous cathode MFCs. The characteristics and performance of EPS were analyzed and compared with other conventionally used separators used in MFCs and was found to be competitive. Initially, the EPS was less impermeable to protons, resulting in delayed process startup (17 days) and stabilization (57 days), but gradually exhibited improved and stable performance. In the air cathode MFC with the EPS as the separator and domestic wastewater as the substrate, power production was 391 mW/m2, while power output of the aqueous cathode MFC was 328 mW/m2. The characteristics and cost analysis of EPS indicate that it can be a potential candidate as a separator in scaled-up MFC applications.

Novel microbial fuel cell design to operate with different wastewaters simultaneously.

A novel single cathode chamber and multiple anode chamber microbial fuel cell design (MAC-MFC) was developed by incorporating multiple anode chambers into a single unit and its performance was checked. During 60 days of operation, performance of MAC-MFC was assessed and compared with standard single anode/cathode chamber microbial fuel cell (SC-MFC). The tests showed that MAC-MFC generated stable and higher power outputs compared with SC-MFC and each anode chamber contributed efficiently. Further, MAC-MFCs were incorporated with different wastewaters in different anode chambers and their behavior in MFC performance was observed. MAC-MFC efficiently treated multiple wastewaters simultaneously at low cost and small space, which claims its candidature for future possible scale-up applications.

Magnetotactic bacteria: nanodrivers of the future.

Magnetotactic bacteria (MTB) represent a heterogeneous group of Gram-negative aquatic prokaryotes with a broad range of morphological types, including vibrioid, coccoid, rod and spirillum. MTBs possess the virtuosity to passively align and actively swim along the magnetic field. Magnetosomes are the trademark nano-ranged intracellular structures of MTB, which comprise magnetic iron-bearing inorganic crystals enveloped by an organic membrane, and are dedicated organelles for their magnetotactic lifestyle. Magnetosomes endue high and even dispersion in aqueous solutions compared with artificial magnetites, claiming them as paragon nanomaterials. MTB and magnetosomes offer high technological potential in modern science, technology and medicines. This review focuses on the applicability of MTB and magnetosomes in various areas of modern benefits.

Microbial fuel cells - Applications for generation of electrical power and beyond.

A Microbial Fuel Cell is a bioelectrochemical device that exploits metabolic activities of living microorganisms for generation of electric current. The usefulness and unique and exclusive architecture of this device has received wide attention recently of engineers and researchers of various disciplines such as microbiologists, chemical engineers, biotechnologists, environment engineers and mechanical engineers, and the subject of MFCs has thereby progressed as a well-developed technology. Sustained innovations and continuous development efforts have established the usefulness of MFCs towards many specialized and value-added applications beyond electricity generation, such as wastewater treatment and implantable body devices. This review is an attempt to provide an update on this rapidly growing technology.

Magnetotactic bacteria: nanodrivers of the future.

Magnetotactic bacteria (MTB) represent a heterogeneous group of Gram-negative aquatic prokaryotes with a broad range of morphological types, including vibrioid, coccoid, rod and spirillum. MTBs possess the virtuosity to passively align and actively swim along the magnetic field. Magnetosomes are the trademark nano-ranged intracellular structures of MTB, which comprise magnetic iron-bearing inorganic crystals enveloped by an organic membrane, and are dedicated organelles for their magnetotactic lifestyle. Magnetosomes endue high and even dispersion in aqueous solutions compared with artificial magnetites, claiming them as paragon nanomaterials. MTB and magnetosomes offer high technological potential in modern science, technology and medicines. This review focuses on the applicability of MTB and magnetosomes in various areas of modern benefits.

Inoculum selection to enhance performance of a microbial fuel cell for electricity generation during wastewater treatment.

Experiments were designed to evaluate the influence of various anaerobic inoculums to enhance microbial fuel cell (MFC) performance utilizing tannery wastewater as substrate. Three bacterial electrogenic strains, tolerant to tannery environment, were isolated from soil contaminated with tannery waste and tannery wastewater was inoculated with these monotypes and mixed consortia of three bacterial strains in different MFCs. Comparative analysis was made by treating the tannery wastewater with foreign microbial consortia (activated sludge inoculum) and with only natural habitat microbes already present in plain wastewater. It was observed that inoculum contributes great effect on the MFC performance. Among the studied inoculation strategies, mixed electrogenic strain inocula enabled higher current yield along with concurrent substrate removal efficiency. On the contrary, plain wastewater resulted in relatively low efficiency.