Heavy metals, including chromium, are associated with developed industrialization and technological processes, causing imbalanced ecosystems and severe health concerns. The current study is of supreme priority because there is no previous work that dealt with the modeling of the optimization of the biosorption process by the immobilized cells. The significant parameters (immobilized bacterial cells, contact time, and initial Cr6+ concentrations), affecting Cr6+ biosorption by immobilized Pseudomonas alcaliphila, was verified, using the Plackett–Burman matrix. For modeling the maximization of Cr6+ biosorption, a comparative approach was created between rotatable central composite design (RCCD) and artificial neural network (ANN) to choose the most fitted model that accurately predicts Cr6+ removal percent by immobilized cells. Experimental data of RCCD was employed to train a feed-forward multilayered perceptron ANN algorithm. The predictive competence of the ANN model was more precise than RCCD when forecasting the best appropriate wastewater treatment. After the biosorption, a new shiny large particle on the bead surface was noticed by the scanning electron microscopy, and an additional peak of Cr6+ was appeared by the energy dispersive X-ray analysis, confirming the role of the immobilized bacteria in the biosorption of Cr6+ ions.
In this study, the pink yeast Rhodotorula sp. strain ATL72 was isolated from salt marches near Mediterranean Sea, Egypt. From phylogenetic analysis, the isolated strain ATL72 was closely related to Rhodotorula bloemfonteinensis EU075187 by similarity of 40%. The biological synthesis of nanosilver (AgNPs) using the marine pink yeast Rhodotorula sp. strain ATL72 was established. The UV-Visible spectral analysis confirmed the synthesis of AgNPs showing a characteristic peak around 400-500 nm. TEM analysis not only confirmed the synthesis of AgNPs but also described the spherical and oval shaped nanoparticle besides size measurements ranged from 8.8 to 21.4 nm. The biosynthesized AgNPs showed a strong antimicrobial activity by causing a complete inhibition of growth for a wide range of Gram positive and Gram negative bacteria as well as fungi with low MIC value. In conclusion, the pink yeast Rhodotorula sp., strain ATL72 isolated from Egypt is a promising new biological source for the synthesis of silver nanoparticles having a potent antimicrobial activity against a wide range of pathogenic bacteria and fungi.
A Fullerene based system is modified in order to increase its solubility and enhance its ability to carry a protein-like structure. The modified structure, which is proposed to act as HIV-1 protease inhibitor, is [C₆₀-C2H4N-(2,4- XCOCH₂OH)C₆H₄], where the X atom is either O, S or Se. The geometry optimization, vibrational spectra and thermodynamics were performed using semiempirical quantum mechanical PM3 method in order to study the proposed compounds. Furthermore, the quantitative structure activity relationship (QSAR) properties of the compounds are calculated at the same level of theory. Results indicate a possible use of the investigated structures as HIV-1 protease inhibitors. The compounds containing oxygen is more stable as compared to the other two compounds.
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