Application of Co-Culture Technology to Enhance Protease Production by Two Halophilic Bacteria,Marinirhabdus sp. and Marinobacter hydrocarbonoclasticus

Although axenic microbial cultures form the basis of many large successful industrial biotechnologies, the production of single commercial microbial strains for use in large environmental biotechnologies such as wastewater treatment has proved less successful. This study aimed to evaluate the potential of the co-culture of two halophilic bacteria, Marinirhabdus sp. and Marinobacter hydrocarbonoclasticus for enhanced protease activity. The co-culture was significantly more productive than monoculture (1.6–2.0 times more growth), with Marinobacter hydrocarbonoclasticus being predominant (64%). In terms of protease activity, enhanced total activity (1.8–2.4 times) was observed in the co-culture. Importantly, protease activity in the co-culture was found to remain active over a much broader range of environmental conditions (temperature 25 °C to 60 °C, pH 4–12, and 10–30% salinity, respectively). This study confirms that the co-culturing of halophilic bacteria represents an economical approach as it resulted in both increased biomass and protease production, the latter which showed activity over arange of environmental conditions.     

Ultrasensitive aptasensing of lysozyme by exploiting the synergistic effect of gold nanoparticle-modified reduced graphene oxide and MWCNTs in a chitosan matrix

Microchimica Acta - The authors describe a lysozyme aptasensor based on the use of gold nanoparticles (AuNP) assembled on the carbon nanotubes, graphene oxide and chitosan. An electrochemical...     

Lead-doped carbon ceramic electrode as a renewable surface composite electrode for the preparation of lead dioxide film and detection of <Emphasis Type="SmallCaps">l</Emphasis>-tyrosine

Lead-doped carbon ceramic electrode as a new type of renewable composite electrode was prepared by mixing the lead powder with electrode matrix before gelation. Pb on the electrode surface was then converted to lead dioxide by the potential scanning of the composite electrode in 0.1 M NaOH solution in the range of ? 0.3 to 0.7 V versus SCE. The composition and morphology of the electrodes were studied by energy dispersive X-ray spectrometry, scanning electron microscopy, and atomic force microscopy techniques. Cyclic voltammetry and chronoamperometry techniques were also used to study the electrocatalytic activity of the modified electrode toward the oxidation of the l-tyrosine. The best results were obtained at a working potential of 0.45 V (vs. SCE) in 0.1 M NaOH solution. The sensor exhibited a good linear response in the range of 5–1458 µM with a coefficient of determination of 0.9963. The detection limit was 0.77 µM, and sensitivity was 37.4 μA mM^?1. In addition, the modified electrode showed high stability and interference-free response for to detection of the l-tyrosine.     

Immobilized Pd on a NHC functionalized metal–organic framework MIL-101(Cr): an efficient heterogeneous catalyst in Suzuki−Miyaura coupling reaction in water

A novel Pd−NHC functionalized metal–organic framework (MOF) based on MIL-101(Cr) was synthesized and used as an efficient heterogeneous catalyst in the C-C bond formation reactions. Using this heterogeneous Pd catalyst system, the Suzuki−Miyaura coupling reaction was accomplished well in water, and coupling products were obtained in good to excellent yields in short reaction time. The Pd−NHC−MIL-101(Cr) was characterized using some different techniques, including Fourier transform-infrared, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, inductively coupled plasma and elemental analysis. The microscopic techniques showed the discrete octahedron structure of MIL-101(Cr), which is also stable after chemical modification process to prepare the catalyst system. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the structure of the catalyst, while no reducing agent was used. It seems that the NHC groups and imidazolium moieties in the structure of the MOF can reduce Pd (II) to Pd (0) species. This modified MOF substrate can also prevent aggregation of Pd nanoparticles, resulting in high stability of them in organic transformation. The Pd−NHC−MIL-101(Cr) catalyst system could be simply extracted from the reaction mixture, providing an efficient synthetic method for the synthesis of biaryls derivatives using the aforementioned coupling reaction. The Pd−NHC−MIL-101(Cr) catalyst could be recycled in this organic reaction with almost consistent catalytic efficiency.     

Novel (thio)barbituric-phenoxy-N-phenylacetamide derivatives as potent urease inhibitors: synthesis,in vitro urease inhibition,and in silico evaluations

Structural Chemistry - A novel series of (thio)barbituric-phenoxy-N-phenylacetamide derivatives 7a-l was synthesized and evaluated against Helicobacter pylori urease. The latter assay revealed that...     

A numerical study of turbulent opposed impinging jets issuing from triangular nozzles with different geometries

In present research, two turbulent opposed impinging air jets issuing from triangular nozzles with fixed and variable exit velocity ratios and different nozzle-to-nozzle distances have been studied numerically and then compared with rectangular and circular nozzles. The finite volume method has been applied for solving mass and momentum equations. The turbulence model being used here is k-ε RNG. Distributions of pressure, turbulence, kinetic energy and its dissipation rate in various regions especially on the impingement regions have been obtained with high accuracy. Study of the nozzle geometries has shown the advantage of triangular nozzles over other geometries. First, the triangle’s base in nozzle geometry has an important role in our study case which, mixing two flows and regions with high turbulence intensity, directly depends on it. Second, our results show that circular and rectangular nozzles have less efficiency than triangular nozzles in mixing applications. Third and last, it was found that the radial jet being created by opposed jets has some similarities to free jets. In this investigation, air in standard atmospheric pressure has been applied as working fluid.