Potential role of Spirulina (Arthrospira) platensis biomass for removal of TiO2NPs -MG hybrid nanocomposite produced after wastewater treatment by TiO2 nanoparticles.

Biosynthesis of titanium dioxide nanoparticles (TiO2NPs) by Sphingomonas paucimobilis B34 bacteria was successfully achieved and followed by UV-Vis spectroscopy. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR) techniques. The biosynthesized TiO2NPs were spherical in shape with an average particle size of 15.6 nm. These TiO2NPs were used as nono-catalyst for removing of malachite green (MG) dye (at 103 mol/L) from wastewater solution. As indicated by the results, the biosynthesized TiO2NPs represented a capable approach for MG removal with up to 83 % efficiency. The removal process was found to follow a pseudo-first-order kinetics. Furthermore, the developed TiO2NPs-MG hybrid nanocomposite was efficiently removed from the medium by using Spirulina platensis cyanobacterial biomass after wastewater treatment. S. platensis biomass was able to remove up to 89.43 % of the hybrid nanocomposite by a biosorption process. The resultant water effluent, after TiO2NPs-MG removal, showed no toxicity towards Vigna radiate L. seedlings implying its safety for agriculture purposes. According to the obtained results, S. platensis living biomass could play a dual re-cycling role, as natural biosorbent for removing both nanoparticles and dye (TiO2NPs-MG hybrid nano-composite) from solution after wastewater treatment for healthier environmental management.

Production, Partial Purification, and Biochemical Characterization of a Thermotolerant Alkaline Metallo-protease from Staphylococcus sciuri.

Protease-producing Staphylococcus sciuri was isolated from poultry soil samples and culture conditions for protease production were optimized. The isolated protease showed a maximum activity of 235.1 U/ml. Enzyme purification procedure involved ammonium sulphate precipitation and Sephacryl S-200 HR gel filtration chromatography (GFC). The purification process resulted in the production of three protease fractions namely protease І (metallo-alkaline protease), II, and IІІ. The metallo-alkaline protease was purified to 25.49-fold with specific activity of 982.22 U/mg and 3.76% recovery. The partially purified metallo-protease was optimally active at pH 10.0 and 70 °C and exhibited thermal stability up to 50 °C. The protease activity was enhanced by Ca2+ and Mg2+, completely inhibited by Hg2+ and Cu2+, and significantly reduced by EDTA. The protease showed significant stability towards various surfactants, including SDS. The Km and Vmax values were 0.68 mg/ml and 166.66 nmol of azocasein/ml/h, respectively, while the activation energy (Ea) was 3.07 Kcal/mol. Hence, it is evident that the produced protease possesses unique characteristics and could be a plausible candidate for various industrial and biotechnological applications.

Effect of combination therapy between thyme oil and ciprofloxacin on ulcer-forming Shigella flexneri.

INTRODUCTION: Shigella flexneri is a Gram-negative bacteria that has the ability to invade the epithelium of the colon and cause colon ulcers. METHODOLOGY: The ability of isolated Shigella flexneri from bloody diarrhea to cause colon ulcers was investigated by histopathological examination via oral administration of the bacteria to adult male albino Sprague-Dawley rats. The antibacterial activity of thyme oil, ciprofloxacin, and their combination were evaluated in vitro and in vivo. RESULTS: Oral administration of 12×108 CFU/mL of S. flexneri was able to cause colon ulcers. Thyme oil had the highest antibacterial activity among other investigated oils (minimum inhibitory concentration [MIC] 150µL/L). Ciprofloxacin had the highest antimicrobial activity against S. flexneri (MIC 0.4mg/L). The synergism between thyme oil and ciprofloxacin showed the maximum growth inhibition of S. flexneri. The synergistic activity of thyme oil and ciprofloxacin succeeded in healing the epithelial surface of the colon and decreased the inflammation of the lamina propria; it also decreased the bacterial load in the infected colon, while the commercial drug failed to heal the colon ulcer. Thyme oil, ciprofloxacin, and their combination showed different degrees of effects on the bacterial cell structure by transmission and scanning electron microscopes. CONCLUSIONS: The combination of thyme oil and ciprofloxacin gave synergistic activity, which proved to be more effective in inhibiting the growth of ulcer-forming S. flexneri, healing the colon ulcer, and decreasing infiltration of the lamina propria with inflammatory cells.