Isolation, characterization and antimicrobial activity of Streptomyces strains from hot spring areas in the northern part of Jordan

A total of 30 Streptomyces isolates (28 from soil and 2 from water) were isolated and purified from hot-springs areas in the northern part of Jordan. Four strains were thermopile. They grew at 45 and 55°C but not at 28°C. Strains were described morphologically on four different media: on glycerol yeast extract, oatmeal, yeast malt-extract and starch casein agar. White and grey color series were the most frequent series on all media. The results showed that glycerol yeast extract and starch casein were the best media for sporulation. And yeast malt-extract was the best medium for the production of soluble pigment. Physiological and biochemical tests showed that the highest number of Streptomyces isolates were able to hydrolyze tyrosine was 26 (87%). This was followed by 25 (83%) for starch, 24 (80%) for urea, 21 (70%) for casein and 10 (33%) for gelatin. Twenty two (73%) strains showed the ability to reduce nitrate and 8 (27%) strains produced melanin. Carbon source utilization showed that 26 (87%) strains were able to utilize L- arabinose, 25 (83%) strains were able to utilize meso-inositol, 8 (27%) strains were able to utilize D-sorbitol, 18 (60%) strains were able to utilize D-mannitol, 28 (93%) strains were able to utilize L-rhamnose and all isolates exhibited the ability to utilize D-fructose and D- glucose. The ability to exhibit antibacterial activity against Escherichia coli and Staphylococcus aureus was detected among 20 and 26% of the isolates, respectively, while the ability to exhibit antifungal activity against Candida albicans was detected among 23% of the isolates. Molecular identification of the 8 antibiotics producers was carried out by PCR technique using two sets of primers specific to Streptomyces 16S rDNA gene sequences; strepB/strepE and strepB/strepF which amplified 520 and 1070 bp, respectively. All these antibiotic producer isolates showed positive results for the genus Streptomyces specific primers.Key words: Characterization, streptomyces, antimicrobial activity, hot springs, thermophile, PCR

Synthesis, Characterization and Application of Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles for Removal of Benzene, Toluene and p-Xylene from Aqueous Solution

The removal of benzene, toluene and p-xylene (BTX) from water is necessary to avoid various health and environmental concerns. Among various techniques, adsorption is suitable and widely used for the removal of BTX from water. In this study, the adsorption of BTX from water was performed using carbon nanotubes that were impregnated with zinc oxide nanoparticles. The impregnation was performed using the wet impregnation technique. The synthesized materials were characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) spectroscopy, thermogravimetric analysis (TGA) and nitrogen adsorption–desorption analysis. In batch adsorption experiments, the effect of adsorbent dosage, initial concentration, and contact time were investigated. The percentage removal for a given time and dosage was in the order of p-xylene > toluene > benzene. The kinetics models’ fitting revealed that the pseudo-second-order model fits well the adsorption of benzene, toluene and p-xylene with R2 > 99.4%. The results of adsorption isotherm fitting revealed the best fit with Sips isotherm model (R2 > 99.7%) and the adsorption capacity was p-xylene: 125 mg/g > toluene: 105 mg/g > benzene: 70 mg/g. This behavior is observed probably due to a decrease in solubility and an increase in the molecular weight of BTX

Synthesis, Characterization and Application of Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles for Removal of Benzene, Toluene and p-Xylene from Aqueous Solution

The removal of benzene, toluene and p-xylene (BTX) from water is necessary to avoid various health and environmental concerns. Among various techniques, adsorption is suitable and widely used for the removal of BTX from water. In this study, the adsorption of BTX from water was performed using carbon nanotubes that were impregnated with zinc oxide nanoparticles. The impregnation was performed using the wet impregnation technique. The synthesized materials were characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) spectroscopy, thermogravimetric analysis (TGA) and nitrogen adsorption–desorption analysis. In batch adsorption experiments, the effect of adsorbent dosage, initial concentration, and contact time were investigated. The percentage removal for a given time and dosage was in the order of p-xylene &gt; toluene &gt; benzene. The kinetics models’ fitting revealed that the pseudo-second-order model fits well the adsorption of benzene, toluene and p-xylene with R2 &gt; 99.4%. The results of adsorption isotherm fitting revealed the best fit with Sips isotherm model (R2 &gt; 99.7%) and the adsorption capacity was p-xylene: 125 mg/g &gt; toluene: 105 mg/g &gt; benzene: 70 mg/g. This behavior is observed probably due to a decrease in solubility and an increase in the molecular weight of BTX.</jats:p

Wet air oxidation of benzene

Processing of petrochemical compounds produces a large amount of wastewater. This wastewater consists of toxic (hazardous) materials that can not be discharged to the environment without treatment. As restrictive environmental constraints increase, new technologies are needed to treat those toxic materials before discharging them to the environment. Wet Air Oxidation (WAO) is one of these new methods.This study casts light on the effect of initial pH on the WAO of benzene at different temperatures and pressures. It was found that at pH 6, a temperature of 260°C and a partial pressure of oxygen of 1.38 MPa around 97% degradation was achieved in one hour. When the initial pH was lowered to 4 more than 90% degradation was achieved at 220°C and PO2 of 1.38 MPa in only 15 minutes.` It was concluded that the higher the temperature the better the benzene degradation, and the faster benzene degradation has been obtained with the increasing partial pressure of oxygen. The main intermediates were acetic acid and formic acid.Furthermore, it was found that the degradation of benzene can be further enhanced in the presence of phenol. The main reason can be attributed to the effect of the free radicals generated from the fast phenol degradation. A simplified pathway for oxidation of benzene was proposed

Reduction of Escherichia coli bacteria from contaminated water by combining hydrogen peroxide, ozone and ultraviolet light

This study demonstrates the reduction of Escherichia coli bacteria from contaminated water when the water is treated with advanced oxidation processes utilising the following combinations: hydrogen peroxide (H2O2) and ozone (O3), ultraviolet light (UV) and hydrogen peroxide (H2O2), and ultraviolet light (UV) and ozone (O3). Approximately 1 × 108cell/mL of E. coli were spiked into water samples contaminated with 500 ppb of methyl tertiary butyl ether (MTBE) and benzene. Water samples were then treated in a bench-scale photoreactor using 15 W low pressure (LP) and 150 W medium pressure (MP) UV lamps. Hydrogen peroxide at 20, 50 and 100 ppm and ozone at 1, 2 and 5 ppm were used along with the UV irradiation to generate the hydroxyl radicals (.OH) needed to degrade organic contaminants such as MTBE and benzene and most likely destroy bacteria. The results of the study showed that, under the study conditions, no effect of benzene or MTBE was observed on the inactivation rate of the bacteria. Moreover, results showed that the combined effect of the LP 15 W UV lamp with 2 ppm O3 or with 50 ppm H2O2 showed the highest inactivation rate of bacteria within 5 min. The H2O2/O3 process showed high disinfection capability at high dosages of peroxide (50 ppm) and O3 (2 and 5 ppm).</jats:p

دراسة فاعلية المضادات الحيوية لبعض النباتات المائية ومستخلصات اطحالب بالأردن

The antimicrobial activity of the extracts of three fresh water green algae, four marine green algae, two brown marine algae and five red marine algae from the Jordanian part of the Aqaba Gulf, together with four aquatic higher plants were screened against E. coli and Staphylococcus aureus. The inhibition zones were observed and measured from the margin of the well containing the plant extract to the beginning of the bacterial growth on nutrient agar plates. The fresh water algae extracts showed the highest antimicrobial activity against both indicator bacteria, while the marine algae were active against Staph. aureus only. The green algae were the most effective followed by the brown and red marine algae. The extracts of Lemna minor, Potamogeton sp., Nastorium officinale and Apium nodiflorum were also active against Staph. aureus only.في هذا البحث أجريت دراسة لتأثير فاعلية المضادات الميكروبية المستخلصة من العينات الاتية : ثلاثة أنواع من الطحالب الخضراء في المياه العذبة ، أربعة أنواع من الطحالب البحرية ، اثنين من الطحالب البنية البحرية ، خمسة أنواع من الطحالب الحمراء البحرية . في مياه خليج العقبة بالأردن بالاضافة إلى أربعة عينات من النباتات الراقية وذلك ضد بكتريا الأيشيريشيا كولاى ، والاستفيلوكوكس أوريس . وقد قيست المناطق الجرداء الخالية من النمو حول حافة الحلقة المحتوية على المستخلص النباتي إلى بداية نمو البكتريا وذلك ببيئة الآجار المغذي . وقد أثبتت التجارب أن مستخلص طحالب المياه العذبة تفرز أكثر أنواع المضادات الميكروبية تأثيرا ضد هذين النوعين من البكتريا ، وكانت مستخلصات الطحالب البحرية نشطة فقط ضد بكتريا الأستفيلوكوكس أوريس ، كما أن مستخلصات نباتات اللينا مينور والبوتا موجيتون كانت فعالة فقط ضد بكتيريا الأستفيلوكوكس أوريس

A Simple Approach to Fabricate Composite Ceramic Membranes Decorated with Functionalized Carbide-Derived Carbon for Oily Wastewater Treatment

Membrane-based oil–water separation has shown huge potential as a remedy to challenge oily wastewater with ease and low energy consumption compared to conventional purification techniques. A set of new composite ceramic membranes was fabricated to separate surfactant-stabilized oil/water (O/W) emulsion. Carbide-derived carbon (CDC) was functionalized by 3-aminopropyltriethoxy silane (APTES) and subsequently deposited on a ceramic alumina support and impregnated with piperazine as an additional amine. The APTES functionalized CDC-loaded membrane was then crosslinked using terephthalyol chloride (TPC). Different loadings of functionalized CDC (50 mg, 100 mg and 200 mg) were employed on the ceramic support resulting in three versions of ceramic membranes (M-50, M-100 and M-200). The fabricated membranes were thoroughly characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Attenuated total teflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Energy dispersive x-ray spectroscopy (EDX) and elemental mapping. The highest permeate flux of 76.05 LMH (L m−2 h−1) at 1 bar using 67.5 ppm oil-in-water emulsion (as feed) was achieved by the M-50 membrane, while an oil separation efficiency of >99% was achieved by using the M-200 membrane. The tested emulsions and their respective permeates were also characterized by optical microscopy to validate the O/W separation performance of the best membrane (M-100). The effect of feed concentration and pressure on permeate flux and oil–water separation efficiency was also studied. A long-term stability test revealed that the M-100 membrane retained its performance for 720 min of continuous operation with a minor decrease in permeate flux, but the O/W separation efficiency remained intact

A Simple Approach to Fabricate Composite Ceramic Membranes Decorated with Functionalized Carbide-Derived Carbon for Oily Wastewater Treatment

Membrane-based oil–water separation has shown huge potential as a remedy to challenge oily wastewater with ease and low energy consumption compared to conventional purification techniques. A set of new composite ceramic membranes was fabricated to separate surfactant-stabilized oil/water (O/W) emulsion. Carbide-derived carbon (CDC) was functionalized by 3-aminopropyltriethoxy silane (APTES) and subsequently deposited on a ceramic alumina support and impregnated with piperazine as an additional amine. The APTES functionalized CDC-loaded membrane was then crosslinked using terephthalyol chloride (TPC). Different loadings of functionalized CDC (50 mg, 100 mg and 200 mg) were employed on the ceramic support resulting in three versions of ceramic membranes (M-50, M-100 and M-200). The fabricated membranes were thoroughly characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD), Attenuated total teflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Energy dispersive x-ray spectroscopy (EDX) and elemental mapping. The highest permeate flux of 76.05 LMH (L m−2 h−1) at 1 bar using 67.5 ppm oil-in-water emulsion (as feed) was achieved by the M-50 membrane, while an oil separation efficiency of &gt;99% was achieved by using the M-200 membrane. The tested emulsions and their respective permeates were also characterized by optical microscopy to validate the O/W separation performance of the best membrane (M-100). The effect of feed concentration and pressure on permeate flux and oil–water separation efficiency was also studied. A long-term stability test revealed that the M-100 membrane retained its performance for 720 min of continuous operation with a minor decrease in permeate flux, but the O/W separation efficiency remained intact.</jats:p