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Background: Nowadays, microbial infections are considered the most important causes of morbidity and mortality. Various microorganisms including biofilm-forming bacteria reported playing a crucial role in such public health concerns. On the other hand, the inefficacy of conventional antimicrobial agents due to various reasons including drug resistance creates a need for the development of effective drug molecules. In this context, nanoparticles can be promisingly used in the management of all such concerns. Objective: The study aimed to evaluate antibacterial and biofilm removal efficacy of various metal nanoparticles against biofilm-forming bacteria. Methods: Various metal nanoparticles including silver (AgNPs), copper (CuNPs) and zinc oxide (ZnONPs) were synthesized from plant leaf extracts of Punica granatum, Citrus medica, and Annona squamosa, respectively. Results: Thus synthesized nanoparticles were evaluated for their antibacterial and biofilm removal efficacies against Enterococcus gallinarum, Staphylococcus haemolyticus, Enterobacter aerogenes, and Salmonella enterica serovar Typhi to propose a promising approach towards management of such pathogens. In vitro antibacterial study demonstrated that AgNPs showed the maximum efficacy against all the test bacteria followed by CuNPs and ZnONPs. Conclusion: Our results indicate that the metal nanoparticles can be effectively used for the removal of biofilm and also as antimicrobial agents for the management of microbial pathogens responsible for dreadful infections.

This study aimed at recovering nutrients from human urine as valorized products through chemical and biological mineralization, and assessing their fertilizer potential. Chemosynthesis of struvite (MgNH₄PO₄ ⋅6H₂O) was accomplished from fresh human urine through chemical mineralization using magnesia, whereas biogenic synthesis was achieved through microbial mineralization by employing a wastewater bacterium (Pseudomonas aeruginosa KUJM KY355382.1). Elemental analysis and other characterization results confirmed the synthesized products as struvite under both chemical and biological synthesis methods. The potential of the chemogenic and biogenic struvite products as slow release fertilizer was reflected in improved plant growth characteristics, including height, fresh weight, dry weight, pod length and seed yield, of cowpea (Vigna unguiculata) compared to the control set. Specially, the seeds obtained per plant were 137.71 and 125.14% higher after application of chemogenic and biogenic struvite, respectively, compared to a no-fertilizer control. When assessing aging effect on struvite’s chemical structure by comparing a 15-year old struvite crystal with the recently synthesized biomineral, the weathered struvite was found to lose NH_4^+ however, retain PO_4^(3-) and Mg^(2+), implying its phosphate supplying potential over a long period. Both the chemogenic and biogenic synthesis routes successfully converted human urine to fertilizer (‘waste into wealth’), but the struvite yield was higher in the case of chemogenic synthesis using magnesia (474 ± 9.64 mg L^−1) than biogenic synthesis employing Pseudomonas aeruginosa KUJM (345 ± 6.08 mg L^−1). Still, the biogenic synthesis is preferred over the chemogenic route because the process is more eco-friendly. Refereed/Peer-reviewed

Refereed/Peer-reviewed This study investigated the role of an allochthonous Gram-positive wastewater bacterium (Bacillus sp. KUJM2) selected through rigorous screening, for the removal of potentially toxic elements (PTEs; As, Cd, Cu, Ni) and promotion of plant growth under PTE-stress conditions. The dried biomass of the bacterial strain removed PTEs (5 mg L−1) from water by 90.17–94.75 and 60.4–81.41%, whereas live cells removed 87.15–91.69 and 57.5–78.8%, respectively, under single-PTE and co-contaminated conditions. When subjected to a single PTE, the bacterial production of indole-3-acetic acid (IAA) reached the maxima with Cu (67.66%) and Ni (64.33%), but Cd showed an inhibitory effect beyond 5 mg L−1 level. The multiple-PTE treatment induced IAA production only up to 5 mg L−1 beyond which inhibition ensued. Enhanced germination rate, germination index and seed production of lentil plant (Lens culinaris) under the bacterial inoculation indicated the plant growth promotion potential of the microbial strain. Lentil plants, as a result of bacterial inoculation, responded with higher shoot length (7.1–27.61%), shoot dry weight (18.22–36.3%) and seed production (19.23–29.17%) under PTE-stress conditions. The PTE uptake in lentil shoots decreased by 67.02–79.85% and 65.94–78.08%, respectively, under single- and multiple-PTE contaminated conditions. Similarly, PTE uptake was reduced in seeds up to 72.82–86.62% and 68.68–85.94%, respectively. The bacteria-mediated inhibition of PTE translocation in lentil plant was confirmed from the translocation factor of the respective PTEs. Thus, the selected bacterium (Bacillus sp. KUJM2) offered considerable potential as a PTE remediating agent, plant growth promoter and regulator of PTE translocation curtailing environmental and human health risks.