Nowadays, the world is experiencing an energy crisis due to extensive globalization and industrialization. Most of the sources of renewable energy are getting depleted, and thus, there is an urge to locate alternative routes to produce energy efficiently. Microbial fuel cell (MFC) is a favorable technology that utilizes electroactive microorganisms acting as a biocatalyst at the anode compartment converting organic matter present in sewage water for bioelectricity production and simultaneously treating wastewater. However, there are certain limitations with a typical stand-alone MFC for efficient energy recovery and its practical implementation, including low power output and high cost associated with treatment. There are various modifications carried out on MFC for eliminating the limitations of a stand-alone MFC. Examples of such modification include integration of microbial fuel cell with capacitive deionization technology, forward osmosis technology, anaerobic digester, and constructed wetland technology. This review describes various integrated MFC systems along with their potential application on an industrial scale for wastewater treatment, biofuel generation, and energy production. As a result, such integration of MFCs with existing systems is urgently needed to address the cost, fouling, durability, and sustainability-related issues of MFCs while also improving the grade of treatment received by effluent.

Biosurfactant-producing microorganisms improve the efficacy of hydrocarbon biodegradation as the biosurfactant is essential in making hydrocarbons available for breakdown. The present study reports the isolation of biosurfactant-producing bacteria that can be used for crude oil remediation and to characterize the biosurfactant generated during the breakdown of crude oil. This study also reports evaluating the synergism and potentiality of biosurfactant-producing bacteria for simultaneous hydrocarbon biodegradation and power generation. Two bacterial strains (Bacillus subtilis strain B1 and Pseudomonas aeruginosa strain B2) were isolated from petroleum-contaminated soils, which are found effective in producing biosurfactants and degrading crude oil as the sole carbon source. B. subtilis B1 exhibited a higher potential for biosurfactant production and crude oil degradation than P. aeruginosa B2. The FTIR and GC-MS analysis were conducted for further characterization of the biosurfactant, which revealed that the surfactant produced by strain B1 and B2 was surfactin and rhamnolipid, respectively. The application of the B1 and B2 co-culture in microbial fuel cells (MFCs) showed synergism among them and resulted in a maximum power density production of 6.3 W/m³ with an open circuit voltage of 970 mV while degrading 2.5% v/v crude oil containing anolyte. The findings indicate that the co-culture of isolated crude oil-degrading strains has great potential for enhanced power generation and the bioremediation of hydrocarbon-contaminated environments. Moreover, the synergism of isolated strains in MFCs suggested their potent applicability in environmental, energy, and industrial sectors as an economical and feasible alternative to the existing technologies.

Metal/metalloid such as cadmium (Cd) is among the most poisonous agents found in the environment. Exposure to these components is still a serious public health problem, particularly at chronic low dosage levels. Cadmium is a significant industrial agent and environmental contaminant that is a primary cause of kidney dysfunction. Cadmium aggregates in the epithelial cells of the proximal tubule after prolonged exposure, leading in polyuria and low-molecular-weight proteinuria. To estimate biomonitoring of B2-microglobulin biomarker is important. The elevation of levels of biomarker will clinically signify kidney dysfunction. B2-Microglobulin is a low molecular weight protein containing immunoglobulin-like sequences. This protein is an essential cell-surface structure since it is part of the HLA complex. Under normal circumstances, B2-microglobulin is generated and shed by numerous cells, mainly lymphocytes, and is detectable in the blood of healthy people. Because of its tiny size, it is generally filtered easily at the glomerulus and catabolized by the kidney’s proximal tubular cells. Increased serum levels are related with impaired renal function and hyperproduction of B2-microglobulin. It is claimed that B2-microglobulin functions as a modulator of lymphocyte surface and a possible immune system regulator. While traditional endpoints such as morphological changes and biochemical parameters for target organ toxicity were effective in assessing the toxicity of high-dose metal/metalloid mixtures, biomarkers, altered haem biosynthesis, and stress proteins, which demonstrated clear responses in assessing the toxicity of low-dose metal/metalloid mixtures. This review mainly emphasises on B2-microglobulin biomarker and it significant and analysis of cadmium (Cd) toxicity.

To date, research on microbial fuel cells (MFCs) has. focused on the production of cost-effective, high-performance electrodes and catalysts. The present study focuses on the synthesis of silver nanoparticles (AgNPs) by Pseudomonas sp. and evaluates their role as an oxygen reduction reaction (ORR) catalyst in an MFC. Biogenic AgNPs were synthesized from Pseudomonas aeruginosa via facile hydrothermal synthesis. The physiochemical characterization of the biogenic AgNPs was conducted via scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-visible spectrum analysis. SEM micrographs showed a spherical cluster of AgNPs of 20–100 nm in size. The oxygen reduction reaction (ORR) ability of the biogenic AgNPs was studied using cyclic voltammetry (CV). The oxygen reduction peaks were observed at 0.43 V, 0.42 V, 0.410 V, and 0.39 V. Different concentrations of biogenic AgNPs (0.25–1.0 mg/cm²) were used as ORR catalysts at the cathode in the MFC. A steady increase in the power production was observed with increasing concentrations of biogenic AgNPs. Biogenic AgNPs loaded with 1.0 mg/cm² exhibited the highest power density (PD_max) of 4.70 W/m³, which was approximately 26.30% higher than the PD_max of the sample loaded with 0.25 mg/cm². The highest COD removal and Coulombic efficiency (CE) were also observed in biogenic AgNPs loaded with 1.0 mg/cm² (83.8% and 11.7%, respectively). However, the opposite trend was observed in the internal resistance of the MFC. The lowest internal resistance was observed in a 1.0 mg/cm² loading (87 Ω), which is attributed to the high oxygen reduction kinetics at the surface of the cathode by the biogenic AgNPs. The results of this study conclude that biogenic AgNPs are a cost-effective, high-performance ORR catalyst in MFCs.