NULLAbstract
Aims: The major aims of this study are to determine the capability of sulphur
oxidizing bacterium (SOB-1) to desulphurize dibenzothiophene (DBT) and
crude oil, detection of the reaction kinetics and identify the proposed pathway
of DBT desulphurization.
Methods and Results: The isolate was genetically identified based on 16S
rRNA gene sequencing as Klebsiella oxytoca and deposited in the Genebank
database under the accession number: MT355440. The HPLC analysis of the
remaining DBT concentration revealed that, SOB-1 could desulphurize 90% of
DBT (0
25 mmol l−1) within 96 h. The maximum production of sulphate ions
from the desulphurization of DBT (0
36 mmol l−1) and crude oil
(0
4 mmol l−1) could be quantitatively detected after 48 h of incubation at
30°C. The high values of correlation coefficient (R2) obtained at all studied
concentrations; suggested that biodesulfurization kinetics of DBT follows the
first-order reaction model. The kinetics studies showed that, DBT may have an
inhibitory effect on SOB-1 when the initial concentration exceeded
0
75 mmol l−1. The GC-MS analysis exhibited four main metabolites rather
than DBT. The most important ones are 2-hydroxybiphenyl (2-HBP) and
methoxybiphenyl n(2-MBP).
Conclusions: Klebsiella oxytoca SOB-1 catalyzes the desulphurization of DBT
through 4S pathway and forms four main metabolic products. The release of
sulphate ion and formation of 2-HBP indicating the elimination of sulphur
group without altering the carbon skeleton of DBT. The bacterial strain could also catalyzes desulphurization of crude oil. The desulphurization kinetics follows the first-order reaction model.
Significance and Impact of the Study: Klebsiella oxytoca SOB-1 could be used as a promising industrial and environmental biodesulfurizing agent as it is not affecting carbon skeleton of thiophenic compounds and forming less toxic metabolic product (2-MBP).

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Data from the Gravity Recovery and Climate
Experiment (GRACE) and outputs of
the CLM4.5 model were used to estimate recharge
and depletion rates for large aquifers,
investigate the connectivity of an aquifer’s
subbasins, and identify barriers and preferred
pathways for groundwater flow within an
aquifer system. The Nubian Sandstone Aquifer
System and its subbasins (Dakhla, Northern
Sudan Platform, and Kufra) in northeast
Africa were used for demonstration purposes,
and findings were tested and verified against
geological, geophysical, remote sensing, geochronologic,
and geochemical data. There are
four major findings. (1) The average annual
precipitation data over recharge areas in the
southern Kufra section and the Northern
Sudan Platform subbasin were estimated
at 54.8 km3, and 32.8 km3, respectively, and
knowing the annual extraction rates over
these two areas (~0.40 ± 0.20 km3), recharge
rates were estimated at 0.78 ± 0.49 km3/yr and
1.44 ± 0.42 km3/yr, respectively. (2) GRACEderived
groundwater depletion rates over the
Dakhla subbasin and the Northern Kufra
section were estimated at 4.44 ± 0.42 km3/yr
and 0.48 ± 0.32 km3/yr, respectively. (3) The
observed depletion in the southern parts of
the Dakhla subbasin is apparently caused
by the presence of the east-west–trending
Uweinat-Aswan basement uplift, which impedes
the south-to-north groundwater flow
and hence reduces replenishment from recharge
areas in the south. (4) A major northeast-
southwest–trending shear zone (Pelusium
shear system) is apparently providing
a preferred groundwater flow pathway from
the Kufra to the Dakhla subbasin. Our integrated
approach provides a replicable and
cost-effective model for better understanding
of the hydrogeologic setting of large aquifers
worldwide and for optimum management of
these groundwater resources.

Data from the Gravity Recovery and Climate
Experiment (GRACE) and outputs of
the CLM4.5 model were used to estimate recharge
and depletion rates for large aquifers,
investigate the connectivity of an aquifer’s
subbasins, and identify barriers and preferred
pathways for groundwater flow within an
aquifer system. The Nubian Sandstone Aquifer
System and its subbasins (Dakhla, Northern
Sudan Platform, and Kufra) in northeast
Africa were used for demonstration purposes,
and findings were tested and verified against
geological, geophysical, remote sensing, geochronologic,
and geochemical data. There are
four major findings. (1) The average annual
precipitation data over recharge areas in the
southern Kufra section and the Northern
Sudan Platform subbasin were estimated
at 54.8 km3, and 32.8 km3, respectively, and
knowing the annual extraction rates over
these two areas (~0.40 ± 0.20 km3), recharge
rates were estimated at 0.78 ± 0.49 km3/yr and
1.44 ± 0.42 km3/yr, respectively. (2) GRACEderived
groundwater depletion rates over the
Dakhla subbasin and the Northern Kufra
section were estimated at 4.44 ± 0.42 km3/yr
and 0.48 ± 0.32 km3/yr, respectively. (3) The
observed depletion in the southern parts of
the Dakhla subbasin is apparently caused
by the presence of the east-west–trending
Uweinat-Aswan basement uplift, which impedes
the south-to-north groundwater flow
and hence reduces replenishment from recharge
areas in the south. (4) A major northeast-
southwest–trending shear zone (Pelusium
shear system) is apparently providing
a preferred groundwater flow pathway from
the Kufra to the Dakhla subbasin. Our integrated
approach provides a replicable and
cost-effective model for better understanding
of the hydrogeologic setting of large aquifers
worldwide and for optimum management of
these groundwater resources.

ABSTRACT The chemical and physical techniques applied for nanoparticles synthesis are mostly high cost and may have harmful effects. So, there is an indigence to synthesize a low cost, high yield, most effective and most stable nanoparticles. The antimicrobial activity of mycosynthesized titanium oxide (TiO2NPs) and silver (AgNPs) nanoparticles from mycelial extract of Penicillium chrysogenum AUMC 6092 was the main target of this study. The antimicrobial activity was assayed against 5 pathogenic Gram- positive (Staphylococcus aureus and Streptococcus sp.) and Gram- negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) bacteria. In addition, 12 human pathogenic fungal strains including some multidrug resistant yeast strains and dermatophytic fungal strains (Epidermophyton floccosum, Microsporum canis, Trichophyton mentagrophytes and T. rubrum) were tested. TiO2NPs and AgNPs synthesized from culture filtrate of Penicillium chrysogenum AUMC 6092 are uniform, spherical and small. The results showed that, generally TiO2NPs and AgNPs had high inhibitory activity against most tested microorganisms, especially when mixed with Tioconazole. TiO2NP2 had the highest inhibitory effect against C. glabrata AUMC 13382, followed by Escherichia coli, Staphylococcus aureus and C. tropicalis AUMC 13378. On the other hand, Staphylococcus aureus and C. glabrata AUMC 13382 were the most sensitive microbial strains towards AgNPs.

ABSTRACT The chemical and physical techniques applied for nanoparticles synthesis are mostly high cost and may have harmful effects. So, there is an indigence to synthesize a low cost, high yield, most effective and most stable nanoparticles. The antimicrobial activity of mycosynthesized titanium oxide (TiO2NPs) and silver (AgNPs) nanoparticles from mycelial extract of Penicillium chrysogenum AUMC 6092 was the main target of this study. The antimicrobial activity was assayed against 5 pathogenic Gram- positive (Staphylococcus aureus and Streptococcus sp.) and Gram- negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) bacteria. In addition, 12 human pathogenic fungal strains including some multidrug resistant yeast strains and dermatophytic fungal strains (Epidermophyton floccosum, Microsporum canis, Trichophyton mentagrophytes and T. rubrum) were tested. TiO2NPs and AgNPs synthesized from culture filtrate of Penicillium chrysogenum AUMC 6092 are uniform, spherical and small. The results showed that, generally TiO2NPs and AgNPs had high inhibitory activity against most tested microorganisms, especially when mixed with Tioconazole. TiO2NP2 had the highest inhibitory effect against C. glabrata AUMC 13382, followed by Escherichia coli, Staphylococcus aureus and C. tropicalis AUMC 13378. On the other hand, Staphylococcus aureus and C. glabrata AUMC 13382 were the most sensitive microbial strains towards AgNPs.

Abstract:
Background: The presence of anthraquinone (Disperse blue 64) and azodyes (Acid yellow 17) in a waterbody are considered among the most dangerous pollutants.

Methods: In this study, two different isolated microbes, bacterium and fungus, were individually and as a co-culture applied for the degradation of Disperse Blue 64 (DB 64) and Acid Yellow 17 (AY 17) dyes. The isolates were genetically identified based upon 16S (for bacteria) and ITS/5.8S (for fungus) rRNA genes sequences as Pseudomoans aeruginosa and Aspergillus flavus, respectively.
Results: The fungal/bacterial consortium exhibited a higher percentage of dyes degradation than the individual strains, even at a high concentration of 300 mg/L. Azoreductase could be identified as the main catabolic enzyme and the consortium could induce azoreductase enzyme in the presence of both dyes. However, the specific substrate which achieved the highest azoreductase specific activity was Methyl red (MR) (3.5 U/mg protein). The tentatively proposed metabolites that were detected by HPLC/MS suggested that the reduction process catalyzed the degradation of dyes. The metabolites produced by the action consortium on two dyes were safe on Vicia faba and Triticum vulgaris germination and health of seedlings. Toxicity of the dyes and their degradation products on the plant was different according to the type and chemistry of these compounds as well as the type of irrigated seeds.
Conclusion: We submit that the effective microbial degradation of DB64 and AY17 dyes will lead to safer metabolic products.