Date nawah powder as a promising waste for ß-mannanase production from a new isolate Aspergillus niger MSSFW, statistically improving production and enzymatic characterization.

ß-Mannanase producing fungus was isolated from coffee powder waste and identified as Aspergillus niger MSSFW (Gen Bank accession number OR668928). Dates nawah powder as industrial and agricultural waste was the most inducer of ß-mannanase production. The Plackett-Burman and Central Composite designs were used to improve ß-mannanase titer. Optimization studies enhanced the enzyme yield with approximate 13.50-times. ß-Mannanase was purified by Sephadex G-150 gel filtration column and the molecular weight was estimated to be 60 kDa by SDS-PAGE. Crude and purified ß-mannanase displayed maximum activity at temperature 60 °C and 50 °C, respectively. Crude ß-mannanase showed an activation energy value 2.35-times higher than the purified enzyme. Activation energy for thermal denaturation of the purified ß-mannanase was 1.08-times higher than that of the crude enzyme. Purified ß-mannanase exhibited higher deactivation rate constant (Kd) and lower half-life (t0.5) and decimal reduction time (D-value) compared with the crude enzyme. Thermodynamic parameters of enthalpy, entropy, and free energy values for crude and purified ß-mannanase were calculated. Substrate kinetic parameters suggested that the purified ß-mannanase had a strong affinity toward locust bean gum by showing 3.44-times lower Km and 1.99-times higher Vmax compared to the crude enzyme.

Mesoporous Ag-functionalized magnetic activated carbon-based agro-waste for efficient removal of Pb(II), Cd(II), and microorganisms from wastewater.

Herein, eco-friendly mesoporous magnetic activated carbon-based agro-waste nanosorbents incorporating antimicrobial silver nanoparticles (Mag@AC1-Ag and Mag@AC1-Ag) have been prepared. Various techniques (XRD, SEM/EDX, TEM, FTIR, and BET analysis) were employed to characterize the prepared nanosorbents before being utilized as novel nanosorbents to remove Pb+2 and Cd+2 ions. Mag@AC1-Ag and Mag@AC1-Ag exhibited rapid and excellent uptake of Pb+2 and Cd+2. The pseudo-second-order kinetics and the Langmuir isotherm are more suitable for the explanation of the experimental results. The thermodynamic parameters showed that the Pb+2 and Cd+2 sorption by the nanosorbents was a spontaneous and endothermic reaction. The prepared nanosorbents can be effectively regenerated using HCl and recycled up to the fifth cycle. These nanosorbents' potential uses for eliminating Pb+2 and Cd+2 from real water samples were evaluated. Moreover, the results revealed that both Mag@AC1-Ag and Mag@AC2-Ag exhibited high antimicrobial activity against fecal coliform (gram-negative) and Bacillus subtilis (gram-positive).

Synthesis and molecular modeling of new benzimidazoles as glutathione S-transferase inhibitors and anticancer agents.

AIM: Synthesis of novel glutathione S-transferases (GSTs) inhibitors constitutes a promising strategy in cancer treatment. Results & methodology: A new set of benzimidazoles clubbed with various heterocycles as GST inhibitors and anticancer agents were synthesized. The biological results proved the potential of the new compounds as GST inhibitors, specifically compounds 7 and 14 which produced more potency than ethacrynic acid by three- and tenfold, respectively. Most compounds exhibited promising cytotoxic activity against breast and colon cancer cell lines. Molecular modeling studies revealed that compounds 7 and 14 showed good binding with the amino acids of the GST protein. CONCLUSION: Both compounds 7 and 14 fulfilled the Lipinski's rule of five suggesting them as new promising GST inhibitors and anticancer agents.

Inhibition of the recombinant cattle tick Rhipicephalus (Boophilus) annulatus glutathione S-transferase.

Rhipicephalus (Boophilus) annulatus is a bloodsucking ectoparasite that causes severe production losses in the cattle industry. This study aims to evaluate the in vitro effects of tannic acid, hematin (GST inhibitors) and different plant extracts (rich in tannic acid) on the activity of the recombinant glutathione S-transferase enzyme of the Egyptian cattle tick R. annulatus (rRaGST), in order to confirm their ability to inhibit the parasitic essential detoxification enzyme glutathione S-transferase. Extraction with 70% ethanol of Hibiscus cannabinus (kenaf flowers), Punica granatum (red and white pomegranate peel), Musa acuminata (banana peel) (Musaceae), Medicago sativa (alfalfa seeds), Tamarindus indicus (seed) and Cuminum cyminum (cumin seed) were used to assess: (i) inhibitory capacities of rRaGST and (ii) their phenolic and flavonoid contents. Ethanol extraction of red pomegranate peel contained the highest content of phenolic compounds (29.95mg gallic acid/g dry tissue) compared to the other studied plant extracts. The highest inhibition activities of rRaGST were obtained with kenaf and red pomegranate peel (P. granatum) extracts with IC50 values of 0.123 and 0.136mg dry tissue/ml, respectively. Tannic acid was the more effective inhibitor of rRaGST with an IC50 value equal to 4.57µM compared to delphinidine-HCl (IC50=14.9±3.1µM). Gossypol had a weak inhibitory effect (IC50=43.7µM), and caffeic acid had almost no effect on tick GST activity. The IC50 values qualify ethacrynic acid as a potent inhibitor of rRaGST activity (IC50=0.034µM). Cibacron blue and hematin showed a considerable inhibition effect on rRaGST activity, and their IC50 values were 0.13µM and 7.5µM, respectively. The activity of rRaGST was highest for CDNB (30.2µmol/min/mg protein). The enzyme had also a peroxidatic activity (the specific activity equals 26.5µmol/min/mg protein). Both tannic acid and hematin inhibited rRaGST activity non-competitively with respect to GSH and competitively with respect to CDNB. While red pomegranate extracts inhibited rRaGST activity competitively with respect to GSH, uncompetitive inhibition was observed with respect to CDNB.