Removal of fenamiphos, imidacloprid, and oxamyl pesticides from water by microalgal Nannochloropsis oculata biomass and their determination by validated HPLC method.

The present study assessed the removal of fenamiphos, imidacloprid, and oxamyl pesticides from water using algal Nannochloropsis oculata biomass. Several factors, such as algal biomass concentration, incubation time, and pesticide concentration, were studied for their impact on pesticide removal. Analysis and quantification of pesticides by rapid HPLC have been developed and validated. The optimum conditions were obtained at 15 min, 50 mg/L of pesticide concentration, and 4,500 mg/L of the algal biomass with 92.24% and 90.43% removal for fenamiphos and imidacloprid, respectively. While optimum parameters of 10 min incubation, 250 mg/L of pesticide concentration, and 2,750 mg/L of the algal biomass exhibited 67.34% removal for oxamyl. N. oculata, marine microalgae, successively removed different concentrations of the tested pesticides from water, and the algal biomass showed a potential reduction of pesticides in polluted water samples.

Structure and antimicrobial comparison between N-(benzyl) chitosan derivatives and N-(benzyl) chitosan tripolyphosphate nanoparticles against bacteria, fungi, and yeast.

Chitosan (Ch) was reacted with seven benzaldehyde analogs separately through reductive amination in which the corresponding imines were formed and followed by reduction to produce N-(benzyl) chitosan (NBCh) derivatives. 1H NMR spectroscopy was used to characterize the products. The nanoparticles (NPs) of Ch and NBCh derivatives were prepared according to the ionotropic gelation mechanism between Ch products and sodium tripolyphosphate, followed by high-energy ultrasonication. Scanning electron microscopy, particle size, polydispersity index, and zeta potential were applied for the NPs examination. The particle size was ranged from 235.17 to 686.90 nm and narrow size distribution (PDI <1). The zeta potential of NPs was varied between -1.26 and -27.50 mV. The antimicrobial activity was evaluated against bacteria (Erwinia carotovora subsp. atroseptica, Erwinia carotovora subsp. carotovora, and Ralstonia solanacearum), fungi (Aspergillus flavus and Aspergillus niger), and yeast (Candida albicans). The action of NBCh derivatives was significantly higher than Ch. The NPs had considerably higher than the Ch and NBCh derivatives. The activity was directly proportional to the chemical derivatization of Ch and the zeta potential of the NPs. The antimicrobial efficacy of these derivatives formulated in a greener approach could become an alternative to using traditional antimicrobial applications in an environmentally friendly manner.

Antimicrobial and antioxidant activities of hydrocarbon and oxygenated monoterpenes against some foodborne pathogens through in vitro and in silico studies.

The present work describes the antimicrobial action of 25 monoterpenes (six hydrocarbons, five ketones, two aldehydes, six alcohols and six acetate analogues) against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and antifungal activity against Aspergillus flavus. The antibacterial activity was evaluated by broth microdilution technique as a minimum inhibitory concentration (MIC) and the antifungal activity was performed by mycelia radial growth technique as the effective concentration causing 50% inhibition of the mycelial growth (EC50). The results showed that thymol and α-terpineol were the most potent against E. coli (MIC = 45 and 55 mg/L, respectively) and S. aureus (MIC = 135 and 225 mg/L, respectively). The results also showed that thymol displayed the maximum antifungal action against A. flavus with EC50 20 mg/L. Furthermore, the antioxidant activity was determined using N,N-dimethyl-1,4-phenylenediamine (DMPD) and the results showed that geraniol were the most potent compound (IC50 = 19 mg/L). Molecular docking studies indicated that the compounds displayed different binding interactions with the amino acid residues at the catalytic sites of N5-carboxyaminoimidazole synthetase and oxysterol binding protein Osh4 enzymes. Non-covalent interactions including van der Waals, hydrogen bonding as well as hydrophobic were observed between the compounds and the enzymes. A significant relationship was found between the docking score and the biological activity of the tested monoterpenes compared to the ceftriaxone and carbendazim as standard bactericide and fungicide, respectively. In silico ADMET properties were also performed and displayed potential for the development of promising antimicrobial agents. For these reasons, these compounds may be considered as potential ecofriendly alternatives in food preservation to delay or prevent the microbial infection and prolong the shelf life of food products.