Rakesh Kumar Sharma

Introduction: Plant-derived bionanomaterials have emerged as an important interest as a sustainable platform for new drug delivery and antimicrobial applications. In this study, biopolymer-based lignin nanoparticles were synthesized using wheat straw lignin. Method: Lignin from wheat straw was extracted and used for the preparation of nanoparticles. The lignin nanoparticles (LNPs) were then characterized using UV–visible spectroscopy, scanning electron microscopy, Fourier transform infrared, and the engineered LNPs were then mixed with cell-free supernatant (CFS) of Lactiplantibacillus plantarum to build a multifunctional, antibiotic-free nanotherapeutic system against dermatological pathogens Cutibacterium acnes using Aloe vera gel. All the combinations were checked for growth and biofilm inhibition of the pathogen. Results: Spherical to subspherical LNPs were formed with a mean diameter ranging between 53 and 107 nm. These LNPs in combination with the postbiotic showed excellent growth inhibition of C. acnes (95.5%) in broth assays, compared to the postbiotic CFS alone (63.6%) and the conventional antibiotic azithromycin (35.9%). Quantitative fluorescence microscopy also confirmed a significant decrease in the amount of bacteria associated with the biofilm (47.5% relative fluorescent compared to 58.0% for azithromycin). The formulated nanocomposite gel also demonstrated strong 2, 2-diphenyl-1-picrylhydrazyl free radical-scavenging activity, with an in vitro sun protection factor (SPF) of 10.0, compared to an SPF of 0.53 for the base gel. Discussion: The improved antimicrobial and antibiofilm activities of the LNP–postbiotic formulation indicate a combined interaction between wheat straw-derived lignin nanoparticles and L . plantarum postbiotic metabolites, leading to greater C. acnes inhibition than the individual components and the tested azithromycin control. The antioxidant and photoprotective properties of the nanocomposite gel provide additional proof of its potential as a multifunctional, sustainable, antibiotic-free topical biomaterial for acne treatment. However, further investigation may be required to assess its physicochemical stability, skin compatibility, permeation, and in vivo therapeutic efficacy.

The present study investigates the performance of single-chambered microbial fuel cell in the presence and absence of heavy metal (CoCl₂). The developed cell was further evaluated for its potential application in heavy metal sensing based on its electrochemical performance. A portable MFC was fabricated using 3 cm polyethylene tube. Pichia fermentans was used an exoelextrogenic yeast and the electrochemical response of the MFC were examined over 220 min, using varying external resistances ranging from 33 Ω to 1 MΩ. Cobalt chloride solution was added to the cells to assess the impact of heavy metal on MFC performance. Voltage, power density, and current density, cyclic voltammetry at different scan rates were recorded and analyzed to evaluate the sensor's effectiveness. The MFC without metal exhibited a steady increase in voltage over time, peaking at 90 mV at 220 min, with the highest power density and current density observed at lower external resistance. As resistance increased, the power output declined sharply. In contrast, the cobalt chloride-injected system showed a lower voltage of 40 mV under the same experimental conditions. Thus, the study demonstrated that the yeast based portable MFC exhibit excellent sensitivity to environmental contaminants such as cobalt chloride, making them highly suitable for heavy metal biosensing applications.

The development of innovative bioprocessing technologies has resulted from the growing global need for sustainable forms of energy and environmentally friendly waste treatment. In this review, we focus on the combined electro-fermentation and microbial fuel cells, as they form a hybrid system that simultaneously addresses wastewater treatment, bioenergy production, and bioplastics. Even though microbial fuel cells produce electricity out of the organic waste by the use of electroactive microorganisms, electro-fermentation improves the microbial pathways through the external electrochemical management. The novelty of the review is that it compares the two technologies in detail and identifies the synergistic potential of the technologies as well as assesses the efficiencies of their operations, scalability, and impact on the environment. The research utilizing Scopus and PubMed directories was done by means of a systematic literature review that included 147 peer-reviewed experimentation and technology-oriented studies published during the period of 2012–2024. The main results lead to the conclusion that integrated systems imply significant increase in power densities (up to 2000 mW/m²), the enhancement of electron transfer efficiency (increased by 30–40%), large-scale production of useful products such as methane, hydrogen and organic acids. In spite of this promise, there are still difficulties regarding microbial stability, material costs, and energy balance. The review identifies the existing gaps and future opportunities, which include the development of novel electrode materials, the employment of better reactor designs and designer microbial consortia. The combination of such systems may become an interesting strategy of the next generation of biorefineries and have a good prospect to become a part of the circular economy and climate as a whole. Graphical Abstract

Microbial fuel cells (MFCs) have emerged as a promising technology to convert biomass and organic waste into electricity, offering an eco-friendly and sustainable alternative to fossil fuels. Recent innovations in nanotechnology have significantly enhanced the performance and efficiency of MFCs by improving electron transfer rates, expanding surface areas, and optimizing the properties of anode and cathode materials. This review provides a detailed assessment of the fundamental and functional components of MFCs. These components include the anode, which facilitates the oxidation of organic matter, and the cathode, where the reduction of oxygen or other electron acceptors occurs. Another critical component is the proton exchange membrane (PEM), which allows the transfer of protons from the anode to the cathode while preventing oxygen from diffusing into the anode chamber. In addition to discussing these key elements, the article explores the role of various microorganisms involved in MFCs. These microorganisms, which include both naturally occurring species and genetically engineered strains, play a vital role in facilitating extracellular electron transfer (EET), a process that enables the conversion of chemical energy stored in organic compounds into electrical energy. We analyze different biomass pretreatment strategies, such as physical, chemical, and biological approaches, that enhance the breakdown of lignocellulosic biomass to improve energy output. Furthermore, the review highlights optimization techniques for improving biomass-powered MFC performance, such as electrode modification, pH control, and organic loading rate management. The application potential of MFCs is extensively discussed, covering bioremediation, wastewater treatment, biosensors, and power generation, with a particular focus on MFC-based biosensors for environmental monitoring and medical diagnostics. Despite their immense potential, challenges such as low power output, biofouling, and high operational costs hinder large-scale commercialization. To address these issues, we propose innovative strategies, including the integration of nanomaterials, electroactive microorganisms, and advanced membrane designs, to enhance the efficiency and reliability of MFCs. We conclude that nanotechnology-enabled MFCs, combined with engineered microbes and optimized system designs, hold immense potential for revolutionizing sustainable energy generation and biosensing applications, paving the way for a cleaner and more efficient future.

Lignin nanoparticles (LNPs) present a promising alternative owing to several beneficial characteristics as compared to conventional metal and other nanoparticles. They are cost‐effective, eco‐friendly, biocompatible, and biodegradable. This study aimed to synthesize and characterize LNP‐based antimicrobial and ultraviolet (UV) barrier textiles, alongside a novel antimicrobial UV‐barrier sunscreen formulation. LNPs were synthesized via acid precipitation, and the particle size and morphology characterized through scanning electron microscopy (SEM). The antimicrobial efficacy and UV shielding properties of the LNPs were quantitatively assessed using spectrophotometric methods. LNPs range from 70 nm to 200 nm as observed under SEM analysis and also showed the presence of LNPs on the cotton cloth. Both LNPs and LNPs containing cloth demonstrated antimicrobial properties against tested bacterial ( E. coli and P. aeruginosa) and fungal ( Aspergillus niger and Penicillium sp .) strains. LNPs demonstrate minimum inhibitory concentration of 1.5 mg/mL against E. coli . The distinctive properties of LNPs, specifically their antimicrobial, and UV barrier capabilities, position them as promising candidates for applications. Thus, LNPs offer eco‐friendly, UV‐protective, and antimicrobial properties, enhancing sustainability in textiles and also in skincare by providing natural antioxidants and UV shielding.

Heavy metals contamination poses a significant environmental threat, which requires the development of eco‐friendly bioremediation techniques. Present research work was conducted using wheat straw in submerged conditions for the growth of white rot fungus, Phlebia brevispora in the presence of varying concentrations of Cd, Pb, Ni, and Cr. The lignocellulolytic enzyme production ability of fungus was monitored. A wheat straw‐based fixed‐bed bioreactor was designed to treat metal‐containing water in continuous mode. The fungus showed a positive influence on laccase production, cellulase production, and lignin peroxidase activity. As observed through atomic absorption spectroscopy (AAS), Cr removal efficiency was 78%–80%, regardless of the initial metal concentration. The Cr was also found on the surface of fungal mycelium as per the results obtained from SEM–EDX. The continuous bioreactor achieved 98%–99% metal removal, making it a natural and cost‐effective solution for metal removal from wastewater using P. brevispora.

Lignocellulolytic enzymes are used in different industrial and environmental processes. The rigorous operating circumstances of these industries, however, might prevent these enzymes from performing as intended. On the other side, extremozymes are enzymes produced by extremophiles that can function in extremely acidic or basic; hot or cold; under high or low salinity conditions. These severe conditions might denature the normal enzymes that are produced by mesophilic microorganisms. The increased stability of these enzymes has been contributed to a number of conformational modifications in their structures. These modifications may result from a few amino acid substitutions, an improved hydrophobic core, the existence of extra ion pairs and salt bridges, an increase in compactness, or an increase in positively charged amino acids. These enzymes are the best option for industrial and bioremediation activities that must be carried out under difficult conditions due to their improved stability. The review, therefore, discusses lignocellulolytic extremozymes, their structure and mechanisms along with industrial and biotechnological applications.