Marine pigmented bacteria are a promising natural source of carotenoids.Kocuriasp. RAM1 was isolated from the Red SeaBohadschia graeffeicollected from Marsa Alam, Egypt, and used for carotenoids production. The extracted carotenoids were purified by thin-layer chromatography (TLC). The characteristic UV absorbance of the three purified fractions gave us an inkling of what the purified pigments were. The chemical structures were confirmed by nuclear magnetic resonance spectroscopy (NMR) and LC-ESI-QTOF-MS/MS. The three different red pigments were identified as two C₅₀-carotenoids, namely bisanhydrobacterioruberin and trisanhydrobacterioruberin, in addition to 3,4,3ʹ,4ʹ-Tetrahydrospirilloxanthin (C₄₂-carotenoids).Kocuriasp. RAM1 carotenoids were investigated for multiple activities, including antimicrobial, anti-inflammatory, antioxidant, anti-HSV-1, anticancer, antidiabetic and wound healing. These new observations suggest thatKocuriasp. RAM1 carotenoids can be used as a distinctive natural pigment with potent properties.

Background: Metal oxide nanoparticles (NPs) are becoming valuable due to their novel applications. The green synthesis of TiO₂ NPs is more popular as a flexible and eco-friendly method compared to traditional chemical synthesis methods. TiO₂ NPs are the most commonly used semiconductor in dye-sensitized solar cells (DSSCs). Results: The biogenic TiO₂ NPs were produced extracellularly by the marine halophilic bacterium Halomonas sp. RAM2. Response surface methodology (RSM) was used to optimize the biosynthesis process, resulting in a starting TiO₂ concentration of 0.031 M and a pH of 5 for 92 min (⁓15 nm). TiO₂ NPs were well-characterized after the calcination process at different temperatures of 500, 600, 700 and 800 °C. Anatase TiO₂ NPs (calcined at 500 °C) with a smaller surface area and a wider bandgap were nominated for use in natural dye-sensitized solar cells (NDSSCs). The natural dye used as a photosensitizer is a mixture of three carotenoids extracted from the marine bacterium Kocuria sp. RAM1. NDSSCs were evaluated under standard illumination. After optimization of the counter electrode, NDSSC_Bio(10) (10 layers) demonstrated the highest photoelectric conversion efficiency (η) of 0.44%, which was almost as good as NDSSC_P25 (0.55%). Conclusion: The obtained results confirmed the successful green synthesis of TiO₂ NPs and suggested a novel use in combination with bacterial carotenoids in DSSC fabrication, which represents an initial step for further efficiency enhancement studies.

This study developed a novel, eco-friendly solid-phase extraction (SPE) sorbent, modified pomegranate biochar (POM), from the agricultural waste of pomegranate peel for the efficient removal of toxic lead (Pb(II)) and the tetracycline (TC) antibiotic from aqueous solutions. Synthesized POM was comprehensively characterized using (SEM, TEM, FT-IR, and XRD) and confirmed POM’s hierarchical core-shell nanostructure, enriched surface functional groups. Optimized SPE conditions using POM achieved maximum adsorption capacities of 3900 ± 71 (RSD = 1.8%, n = 3) µmol/g for Pb(II) at (pH 7, 20 s microwave-assisted) and 87.6% ± 0.18 (RSD = 0.001%, n = 3) removal for TC at (pH 4, 30 min shaking). while PO achieved (2000 ± 71 (RSD = 2.8%, n = 3) µmol/g Pb(II); and 45.9% ± 1.8 (RSD = 0.03%, n = 3) TC removal). Although the pseudo-second-order (PSO) model accurately describes the kinetic data for Pb(II) adsorption on POM and PO, this alone does not prove a chemisorption mechanism. In general, the thermodynamic parameters, especially ΔH°, have proved that the primary mechanism is physisorption; nevertheless, the excellent fit to the PSO model suggests that the adsorption process may incorporate certain characteristics of chemisorption or that the rate-limiting step involves the sharing or exchange of electrons. While TC obeys the pseudo-first order model, indicating a physisorption mechanism for both POM and PO. Additionally, the Langmuir model provides the best fit for both POM and PO with Pb(II) and TC, indicating the formation of a monolayer on the adsorbent surface. Efficient desorption used 1 M HCl for Pb(II) (98.7% recovery) and acidified methanol (1:1 v/v HCl: methanol) for TC (99.3% recovery). The Limit of Detection (LOD) and limit of quantification (LOQ) for TC were 1.725 ppm and 5.227 ppm, while Pb(II) ions were 16.27 ppm and 50.06 ppm, respectively. The thermodynamic parameters for the adsorption of Pb(II) and TC onto both POM and PO confirm a spontaneous and endothermic process driven by an increase in entropy. POM also exhibited antibacterial activity comparable to that of a standard antibiotic, particularly against Gram-negative bacteria ( E. coli and P. aeruginosa ).

Background: Menaquinone (MK), which is also known as vitamin K2, is a kind of lipoquinone that, unlike humans, is biosynthesized in bacteria through a series of steps as a necessary component of their respiratory chain for electron transport among various components of the bacterial cell membrane. MKs are receiving increasing attention as they play several essential biological roles in humans. Results: In this study, MK was obtained from Kocuria sp. RAM1, characterized using UV absorbance, and validated using nuclear magnetic resonance spectroscopy (NMR) and liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS). The chemical characterization revealed a total of six MK analogues that were identified and confirmed as MK-1, MK-3, MK-5 (H2), MK-7 (H6), MK-8 (H2), and MK-9. Subsequent to the execution of a significant optimization model, a total KMs of 394.69 µg/ml was obtained, with the MK-1 analog being the dominant one. The antibacterial, anti-inflammatory, antioxidant, anticancer, antidiabetic, and wound-healing activities of MKs were evaluated in vitro. As a result, we discovered that MKs have promising findings on the tested in vitro activities. Conclusions: Our study was made to evaluate MKs obtained from the Red Sea Kocuria sp. RAM1 to emphasize their significant role in different biological applications. Therefore, from a therapeutic and medicinal perspective, the extracted MKs are interesting for additional in vivo studies.

Silver nanoparticles (AgNPs) are gaining traction in many industries and sectors due to their exceptional physical and chemical characteristics. The purpos