The synthesis of silver nanoparticles (AgNPs) using bacteria is more interesting because of their non-toxic, biocompatible, environmentally friendly, and cost-effectiveness. In the present research work, AgNPs were synthesized by Klebsiella pneumoniae in two steps: first, K. pneumoniae was grown in nutrient broth, followed by mixing of bacterial supernatant and silver nitrate aqueous solution in an optimized ratio. The synthesized AgNPs were thoroughly analyzed using analytical instruments for a detailed investigation. The absorption peak observed using UV-visible spectrophotometry at 464 nm indicated the development of AgNPs, while the characteristic bands for the AgNPs by infrared spectroscopy were observed in the region of 500–4,000 cm ⁻¹ . Morphological examination via field emission SEM unveiled spherical-shaped AgNPs whose sizes varied from 22.25 to 47.99 nm, along with high aggregation. The crystallinity nature of the synthesized AgNPs was demonstrated by X-ray diffraction, which revealed major intensity peaks at 2 θ values of 27.6°, 31.9°, and 46°. AgNPs showed 26.6% of methyl orange dye removal within 50 min. The antibacterial activities against Bacillus cereus , Bacillus megaterium , Serratia marcescens , and Staphylococcus aureus showed maximum zones of inhibition, i.e., 14 mm (10 mg·mL ⁻¹ ), 16 mm (5 and 10 mg·mL ⁻¹ ), 13 mm (5 and 10 mg·mL ⁻¹ ), and 12 mm (10 mg·mL ⁻¹ ). Therefore, the bacterial-synthesized AgNPs exhibited potential application in the field of biomedicine, which may be further used against various other pathogens.

Pendimethalin (PND), a persistent dinitroaniline herbicide, poses significant ecological and human health risks due to its high stability, bioaccumulation, and toxicity. The present study explores microwave-assisted rapid synthesis of carbon nanospheres (CNSs) from Vachellia nilotica biochar (VNBC) for the removal of PND from an aqueous medium. The synthesized CNSs were characterized in detail using Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM)–energy dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET), and pHZPC to confirm the oxygen-rich functional groups, crystalline graphitic domains, spherical morphology, elemental composition, surface area, and surface charge. A batch adsorption study was conducted to evaluate the effect of initial concentration (30 mg L ^-1 –70 mg L ^-1 ), contact time (0 min–150 min), dose (2.5 mg–20 mg), and solution pH (2–12) at room temperature. The maximum removal efficiency (95.8%) and adsorption capacity (76.95 mg g ^-1 ) were achieved at 50 mg L ^-1 PND, pH 10, and a 50 mg dose of CNSs. Adsorption kinetics followed a pseudo-second-order model in linear fitting, while non-linear modeling indicated the dominance of physisorption with intraparticle diffusion, indicating a hybrid mechanism. Isotherm studies showed the Langmuir and Freundlich models best describe the adsorption process, confirming monolayer–multilayer adsorption. Furthermore, the presence of multivalent salts enhanced the removal efficiency through strong ionic bridging interaction and higher regeneration capacity up to five cycles, demonstrating potential toward real-water applicability. Compared to the conventional adsorbent, CNSs exhibited superior performance with rapid synthesis (3 min) and higher capacity. These findings establish biochar-derived CNSs as a cost-effective, eco-friendly, and efficient adsorbent for pesticide remediation in contaminated waters.

Plastic pollution is a pressing environmental challenge, necessitating the development of biodegradable alternatives like polyhydroxybutyrate (PHB). This study focuses on optimizing PHB production by Neobacillus niacini GS1, a bacterium isolated from a municipal dumping site. By utilizing agricultural residues such as corn flour, wheat bran, and peptone as substrates, we aimed to establish an eco-friendly method for biopolymer production, contributing to sustainable agricultural residue management and bioplastic innovation. The bacterium was identified using morphological, biochemical, and molecular techniques. The optimization process involved adjusting variables such as inoculum age, inoculum size, incubation time, agitation rate, incubation temperature, pH of the medium, carbon sources, and nitrogen sources. Response surface methodology (RSM) was employed to identify optimal conditions, with the highest PHB yield of 61.1% achieved under specific conditions: 37 °C, pH 7, and an agitation rate of 150 rpm. These findings underscore the potential of Neobacillus niacini GS1 in converting agro-industrial residues into valuable biopolymers, promoting sustainable bioplastic production, and advancing agricultural residue valorization efforts through the use of eco-friendly materials.

Bacopa monnieri leaf-derived biochar efficiently removes pendimethalin herbicide from water via adsorption, achieving up to 97.56% removal, as revealed by experimental optimization and mechanism analysis.

The extensive environmental pollution caused by petroleum-based plastics highlights the urgent need for sustainable, economically viable alternatives. The practical challenge of enhancing polyhydroxybutyrate (PHB) production with cost-effective agro-industrial residues—rice-bran and corn-flour hydrolysates—has been demonstrated. Bacillus bingmayongensis GS2 was isolated from soil samples collected at the Pirana municipal landfill in Ahmedabad, India, and identified through VITEK-2 biochemical profiling and 16S rDNA sequencing (GenBank accession OQ749793). Initial screening for PHB accumulation was performed using Sudan Black B staining. Optimization via a sequential one-variable-at-a-time (OVAT) approach identified optimal cultivation conditions (36 h inoculum age, 37 °C, pH 7.0, 100 rpm agitation), resulting in a PHB yield of 2.77 g L⁻¹ (66% DCW). Further refinement using a central composite response surface methodology (RSM)—varying rice-bran hydrolysate, corn-flour hydrolysate, peptone concentration, and initial pH—significantly improved the PHB yield to 3.18 g L⁻¹(74% DCW), representing more than a threefold enhancement over unoptimized conditions. Structural validation using Fourier Transform Infrared spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance spectroscopy (¹H-NMR) confirmed the molecular integrity of the produced PHB. That Bacillus bingmayongensis GS2 effectively converts low-cost agro-industrial residues into high-value bioplastics has been demonstrated, indicating substantial industrial potential. Future work will focus on bioreactor scale-up, targeted metabolic-engineering strategies, and comprehensive sustainability evaluations, including life-cycle assessment.