Conversion of waste frying oil into biodiesel using recoverable nanocatalyst based on magnetic graphene oxide supported ternary mixed metal oxide nanoparticles.

The magnetic graphene oxide (GO) supported with heterogeneous ternary mixed metal oxide (MMO) was used as nanocatalyst to enhance the conversion of waste frying oil (WFO) triglycerides to biodiesel via esterification process. In this regard, acidic MGO was modified with three basic metal cations of cerium, zirconium, and strontium oxides to produce heterogeneous MGO@MMO nanocatalyst. The nanocatalyst was characterized by FESEM, TEM, EDX and FTIR. The influence of different parameters such as catalyst material ratio, methanol to oil ratio, contact time, and reaction temperature was studied. Based on the results of effecting parameters, the MGO@MMO nanocatalyst converted WFO to biodiesel with a yield 94%, a reaction time of 90 min, methanol to oil ratio (8:1), and a temperature of 60 °C. Esterification mechanism indicated the MGO@MMO nanocatalyst having both binary Brønsted acid-base sites that increased the conversion yields as compared to MGO and MMO at low temperatures.

Enhanced Production of Biosurfactant from Bacillus subtilis Strain Al-Dhabi-130 under Solid-State Fermentation Using Date Molasses from Saudi Arabia for Bioremediation of Crude-Oil-Contaminated Soils.

Crude oil and its derivatives are the most important pollutants in natural environments. Bioremediation of crude oil using bacteria has emerged as a green cleanup approach in recent years. In this study, biosurfactant-producing Bacillus subtilis strain Al-Dhabi-130 was isolated from the marine soil sediment. This organism was cultured in solid-state fermentation using agro-residues to produce cost-effective biosurfactants for the bioremediation of crude-oil contaminated environments. Date molasses improved biosurfactant production and were used for further optimization studies. The traditional "one-variable-at-a-time approach", "two-level full factorial designs", and a response surface methodology were used to optimize the concentrations of date molasses and nutrient supplements for surfactant production. The optimum bioprocess conditions were 79.3% (v/w) moisture, 34 h incubation period, and 8.3% (v/v) glucose in date molasses. To validate the quadratic model, the production of biosurfactant was performed in triplicate experiments, with yields of 74 mg/g substrate. These findings support the applications of date molasses for the production of biosurfactants by B. subtilis strain Al-Dhabi-130. Analytical experiments revealed that the bacterial strain degraded various aromatic hydrocarbons and n-alkanes within two weeks of culture with 1% crude oil. The crude biosurfactant produced by the B. subtilis strain Al-Dhabi-130 desorbed 89% of applied crude oil from the soil sample. To conclude, biosurfactant-producing bacterial strains can increase emulsification of crude oil and support the degradation of crude oil.

Potential effect of Allium sativum bulb for the treatment of biofilm forming clinical pathogens recovered from periodontal and dental caries.

Biofilm producing clinical bacterial isolates were isolated from periodontal and dental caries samples and identified as, Lactobacillus acidophilus, Streptococcus sanguis, S. salivarius, S. mutansand Staphylococcus aureus. Among the identified bacterial species, S. aureus and S. mutansshowed strong biofilm producing capacity. The other isolated bacteria, Streptococcus sanguis, S. salivarius showed moderate biofilm formation. These pathogens were subjected for the production of extracellular polysaccharides (EPS) in nutrient broth medium and the strain S. aureus synthesized more amounts of EPS (610 ± 11.2 µg/ml) than S. sanguis (480 ± 5.8 µg/ml).EPS production was found to be less in S. salivarius (52 ± 3.8 µg/ml).The solvent extract of A. sativum bulb showed the phytochemicals such as, carbohydrate, total protein, alkaloids, saponins, flavonoids, tannins and sterioids. The solvent extract of A. sativum bulb showed wide ranges of activity against the selected dental pathogens. The difference in antibacterial activity of the solvent extract revealed differences in solubility of phytochemicals in organic solvents. Ethanol extract was highly active againstS. aureus (25 ± 2 mm). The Minimum Inhibitory Concentration (MIC) of crude garlic bulb varied widely and this clearly showed that bacteria exhibits different level of susceptibility to secondary metabolites. MIC value ranged between 20 ± 2 mg/ml and 120 ± 6 mg/ml and Minimum Bactericidal Concentration (MBC) value ranged from 60 ± 5 mg/l to 215 ± 7 mg/ml. To conclude, A. sativum bulb can be effectively used to treat periodontal and dental caries infections.

Green synthesis and characterization of silver nanoparticles from Moringa oleifera flower and assessment of antimicrobial and sensing properties.

The present study aimed to explore the biosynthesis and characterization of silver nanoparticles (AgNPs) from Moringa oleifera flower (MOF) extract and its antimicrobial and sensing properties. The prepared AgNPs were characterized by Transmission Electron Microscopy (TEM), UV-visible spectral analysis (UV-vis), X-Ray Diffraction (X-RD), Energy Dispersive Spectroscopy (EDS), and Fourier Infra-Red Spectroscopy (FTIR) respectively. Antimicrobial and sensing properties of the prepared nanoparticles were also determined. Face-Centered Cubic (FCC) lattice of the AgNPs was observed in X-RD pattern. FTIR measurement evidenced the band pattern at 686, 1653, 2062 and 3456 cm-1 proved the presence of proteins and phenolic components in MOF responsible for reduction. TEM analysis indicated the formation of monodispersed spherical particles with 8 nm. UV-vis of the prepared AgNPs authenticated the surface plasmon resonance (SPR) at 429 nm and stable for six months. AgNPs have produced highest zone of inhibition (ZOI) of 17 mm and 29 mm against Klebsiella pneumoniae and Staphylococcus aureus respectively. In addition, the AgNPs effectively detected the presence of Copper ions from 1 mM to 12 mM concentrations. Copper sensitivity of these biosynthesized nanoparticles was carried out by optical sensor based SPR. Thus the obtained antimicrobial and optical properties, suggested the use of obtained AgNPs in water purification.

Biosynthesis of silver and gold nanoparticles using Musa acuminata colla flower and its pharmaceutical activity against bacteria and anticancer efficacy.

Synthesis of nanoparticles using plant sources as reducing agent has become important, as physical and chemical methods are costlier and affects environment. Hence it is important to develop environment friendly nanoparticle synthesis by avoiding the use of toxic chemicals. The present study aimed to synthesize silver nanoparticles (Ag Nps) and gold nanoparticles (AuNps) using Musa acuminata colla flower and its pharmaceutical activity against extended spectrum beta-lactamase (ESBL) gene producing bacteria and anticancer efficacy. The synthesized Ag and Au NPs were analysed by means of UV-Vis, FTIR, XRD,SEM and EDAX evidenced the bioreduction of Ag+ ions to Ag0 and Au3+ ions to Au0 respectively. Both nanoparticles and flower extracts were studied for antibacterial activity of ESBL gene producing bacteria by disc diffusion and microdilution (Resazurin) method. In vitro anticancer efficacy (MCF-7) and toxicity (VERO) of AgNPs, AuNPs, aqueous extract and ethanol extract of flowers were performed by MTT assay. IC50 value for DPPH analysis was at 390 µg and 460 µg for ethanol and aqueous extract respectively. Total antioxidant content was found be 740 µg/mg and 460 µg/mg for ethanol and aqueous extract. GCMS analysis authenticated the existence of the compounds namely, 9,12-octadecadienoic acid(z,z)- and n-hexadecanoic acid in the crude extract of the samples. Among the samples, AgNPs had best antibacterial activity. AgNPs and AuNPs were confirmed by colour change to reddish brown and ruby red. Further ƛmax were obtained at 474 and 540 nm by UV - visible spectrum. SEM analysis revealed the particle size ranges from 12.6 to 15.7 nm for silver and 10.1 to 15.6 nm for gold nanoparticles. The EDAX spectrum shows a strong signal for elemental Ag and Au at ~ 3 keV and 1.5 keV. The XRD patterns for silver and gold nanoparticles at 36.701, 42.900, 63.281 and 76.398 corresponding to the lattice planes 2.4467, 2.1064, 1.46839, 1.24564 nm and 27.32, 36.7228, 39.56, 42.888, 63.253, 63.253, 65.02 and 76.383 corresponding to the lattice planes 3.262, 2.44530, 2.276, 2.1070, 1.46897, 1.4332 and 1.24585 nm. The IC50 values for MCF-7 and VERO cells were 30.0 µg/ml and 55.0 µg/ml respectively.