Egyptian Soil Research Articles

Degradation of natural rubber latex by new Streptomyces labedae strain ASU-03 isolated from Egyptian soil

Natural rubber latex is one of the problems that raises the environmental concerns. In this study the degrading ability of Ficus elastica rubber latex by a bacterium strain ASU-03, isolated from Egyptian soil was assessed. The strain was able to produce clear zone around its colony on latex rubber containing medium and was identified by conventional methods as Streptomyces sp. Phylogenetic analysis of 16S rRNA (16S rRNA) and RNA polymerase s-subunit (rpoB) genes were applied. Results of the 16S rRNA gene analysis revealed that the strain was highly related to Streptomyces sp. (100% similarity), so the rpoB gene was partially sequenced to clarify the specific name of the isolate. Phylogenetic tree based on rpoB gene sequences indicated that strain ASU-03 was highly similar to the reference strain Streptomyces labedae and both were shared a one cluster. The current results demonstrated that the use of a rpoB gene-based method gives a better resolution in the species level identification. To our knowledge, this species has never been reported to be involved in natural rubber degradation. This was therefore the first report about the degradation of Ficus elastic by S. labedae. The degradation of Ficus elastica rubber latex was determined by measuring the increase in protein content of bacterium (mg/g dry wt), reduction in molecular weight (g/mol) and inherent viscosity (dL/g) of the latex. Moreover the degradation was also confirmed by formation of aldehyde or keto group by Schiff’s reagent and by observing the growth of the Streptomyces strain using scanning electron microscopy.

Effect of Different Sources of Nitrogen Fertilizers Combined with Vermiculite on Productivity of Wheat and Availability of Nitrogen in Sandy Soil in Egypt

Effect of Different Sources of Nitrogen Fertilizers Combined with Vermiculite on Productivity of Wheat and Availability of Nitrogen in Sandy Soil in Egypt

Modeling solute transport by DLA in soils of northeastern Egypt.

Arid soils in Egypt display large variability in solute transport properties, causing problems in soil management. To characterize this variability, dye infiltration experiments were conducted on four plots representing three main soil types in northeastern Egypt. The plots represented both cultivated and uncultivated land use. The observed dye patterns displayed a large variability and especially the clay soils indicated a high degree of preferential flow. The loamy sand and sandy soils displayed a more uniform dye distribution indicating more homogeneous soil properties. The observed dye patterns were modeled using a diffusion limited aggregation (DLA) model. The DLA is a random walk model where model parameters can be optimized using genetic algorithms (GA). The DLA model reproduced the observed dye patterns for all soils in an excellent way. The best fit was obtained with a specific combination of directional random walk probabilities Pu, Pd, Pr, and Pl for each plot (correlation 0.97–0.99). To account for soil layers with different hydraulic properties a two layer DLA model was developed. For all plots the Pu (upward random walk probability) was higher for the upper more homogeneous soil layer. The overall results showed that spatial variability resulting from solute transport for the investigated soils can be modeled using a DLA approach.

Effects of Gypsum Particle Size on Reclaiming Saline-Sodic Soils in Egypt

In Egypt, improving salt-affected soils is important for ensuring secure agricultural productivity. Gypsum is commonly used for the reclamation of saline-sodic and sodic soils. Soil column experiments were conducted to investigate the effect of gypsum, ground to varying degrees of fineness, on the reclamation of clayey saline-sodic soils. The soil used was obtained from Gelbana Village in the Sahl El-Tina Plain, Sinai Governorate, Egypt. Three different degrees of gypsum fineness (<0.5, 0.5–1, and 1.0–2.0 mm) were tested, and the following treatments were included: control (leaching with no gypsum addition), fine particles (<0.5 mm), medium particles (0.5–1.0 mm), and coarse particles (1.0–2.0 mm). The gypsum requirement (GR) to reduce the initial ESP from 29.8 to 10 percent was calculated for the 30-cm soil matrix. The application of gypsum and the subsequent leaching enhanced the reclamation and decreased the salinity as well as the sodicity. With greater fineness of the gypsum particles, a greater decrease in salinity as well as sodicity was obtained. This study suggests that, for greater reclamation efficiency, the gypsum used in the reclamation of saline-sodic soils should be of fine particle size.

Experimental study on the determination of small strain-shear modulus of loess soil

The primary aim of this study was to investigate the collapse potential of loess soil in Egypt, the factors affecting the dynamic properties of this soil and establish relationships between them. Whether engineered or natural, may exist in seismic zones; or may be subjected to small strain vibrations, therefore, there is a need to assess the wetting dynamic properties of collapsible soils.A series of oedoemeter and resonant column tests were conducted to study the effect of applied pressure, void ratio, water content and silt content on the collapse potential (Cp), maximum shear modulus (Gmax) and damping ratio (DT) of the tested samples. The results indicate significant increase in the collapse potential and reduction in (Gmax) with the increase of silt content. The results, also, indicate that the (Cp) is less for sample with higher initial relative densities and initial water content.Test results also show that (Gmax) increases with the increase of confining pressure and relative density. The change in damping properties is not significant under the effect of silt content and water content, and it reduces slightly with the increase of confining pressure and relative density. Empirical equations based on the results of the experimental work were proposed to predict (Gmax) with respect to (Cp), voids ratio and applied pressure.

Molecular Identification of Rhizobium Isolates Nodulating Faba Bean Plants in Egyptian Soils

Eleven isolates of Rhizobium leguminosarum symbiovar. Viciae were isolated from root nodules of Vicia faba L. cultivated in 11 fields and represent different governorates in Egypt. The genetic diversity among the isolates was studied using the 16S rRNA gene partial sequence. The phylogenetic analysis formed two groups of isolates and the values of genetic distances were variable among the studied isolates. The highest value of genetic distance was between the isolates RL6 of North Sinai and RL8 of Dakhalia, while the lowest value was between isolates RL9 of Giza and RL10 of Sharkia. The isolates were evaluated for their tolerance to heavy metals using concentrations of 0.5, 1 and 2 mM of heavy metals (Cu, Pb and Zn). The ability to resist the heavy metals decreased with increase in concentration. At the highest concentration (2 mM), No growth was obtained with addition of Zn and Mn to the growth media, however only 27% of isolates could survive with the same concentration of Pb.

Physiological studies on a locally isolated rhamnolipid producer, Pseudomonas strain

Aim Bacterial strains were isolated from different soil samples and evaluated for their ability to produce biosurfactants. Preliminary identification was made of the selected strain Kh4, as well as of the type of produced biosurfactant. Finally, the most optimum conditions for improving growth and the percentage of reduction in the culture surface tension (ST) were investigated. Materials and methods The genus of the selected strain was preliminarily identified on the basis of some biological tests and characterized pigmentation on a specific medium. Rhamnolipid production was confirmed using both Siegmund Wagner and Dubois methods as well as thin-layer chromatography. Quantitative measurements of the ST of cell-free supernatants were determined using the Du Nouy ring method in order to estimate the amount of biosurfactant produced. Cultivation conditions were studied on the basis of both flask and 7 l stirred tank bioreactor levels. Results A total of 66 bacterial strains were isolated from Egyptian soil and assessed for biosurfactant productivity. The selected isolate, preliminarily identified as a Pseudomonas spp., has the ability to produce rhamnolipid and hence to decrease the ST of the fermentation medium from 60 to about 35 mN/m. The optimum fermentation medium, used for the growth and maximum decrease in ST, was determined. Some physiological parameters such as the initial pH, incubation temperature, and time were also studied. Furthermore, the effect of pH control during the fermentation production of rhamnolipid in a 7 l stirred bioreactor was also studied. Accordingly, a maximum decrease in the ST of the cell-free culture medium of 32 mN/m was reached, confirming the production of a satisfactory level of rhamnolipid biosurfactant. Conclusion These results qualified the locally isolated Pseudomonas spp. Kh4 for use in the bioremediation of hydrocarbon-contaminated sites as well as in petroleum industries.

Anticancer Compounds from Chaetomium globosum

The present work resulted in isolation and purification of two potential anticancer compounds from Chaetomium globosum isolated from Egyptian soil. The two compounds were tested against Michigan Cancer Foundation-7(MCF-7) breast cancer cell line and Hepatocellular carcinoma, Human (HEPG-2) a human liver carcinoma cell line and showed inhibition effect on the proliferation of two cell lines. The structures of the two pure compounds were elucidated by HNMR and Mass spectroscopy as methyl 9-dihydro-8-trihydroxy-9-oxo-Hxanthene- 1-carboxylate as a member of xanthones and (E)-methyl 2-hydroxy-6, 6-dimethyl hept-3-enoate.

Biodegradation of diesel oil wastes for production of biosurfactants by two Actinomycetes strains

Biotechnological studies on production of bio-surfactants by actinomycetes strains that were isolated from Egyptian soil were carried out using some diesel oil waste samples. Two actinomycetes strains were found to give bio-surfactant production up to 40 - % when tested with emulsification test. Effect of carbon and nitrogen sources on bio-surfactant production were tested using urea, ammonium nitrate, ammonium chloride and potassium nitrate. Best results for bio-surfactant production were observed with urea and ammonium nitrate as the main nitrogen source in the biological medium. Best results for bio-surfactant production were observed when using Bushnell Hass medium supplement with % hydrocarbon waste. Ammonium sulfate precipitated samples were further applied on Sephadex LH-20 column to obtain purified products. Results obtained from isolated strains show optimistic results for a successful bioremediation of diesel oil wastes for production of commercial active bio-surfactants that could be used in both industrial and pharmaceutical fields.

Enhanced production of thermostable lipase from Bacillus cereus ASSCRC-P1 in waste frying oil based medium using statistical experimental design

This study aim to isolate, identify and optimize lipase producing strains using frying oil waste. Nine strains were isolated from an Egyptian soil samples. Among the isolates, a potent bacterial candidate ASSCRC-P1 was found to be the most potent lipase producer strain at 60 °C. Genotypic identification of ASSCRC-P1 showed 94% similarity with Bacillus sp. strains. Phylogenetic tree confirmed that ASSCRC-P1 was nearly similar to Bacillus cereus. Therefore, it was given the name Bacillus cereus ASSCRC-P1 and its 16S rRNA nucleotide has been deposited in the GenBank Data Library under the accession number: KJ531440. A sequential optimization strategy, based on statistical experimental designs, was employed to enhance the lipase production by this strain. A 2-level Plackett–Burman design was applied to differentiate between the bioprocess parameters that significantly influence lipase production followed by Box-Behnken design to optimize the amounts of variables which have the highest positive significant effect on lipase production. Overall more than 2.15-fold improvement in lipase production was achieved due to optimization compared to that obtained using the basal medium.

Biodiversity and enzymatic profile of some entomopathogenic fungi

Five fungal isolates belonging to theentomopathogenic fungi where had isolated inBio-insecticide Production Unit, Plant Protection Research Institute , two isolatesof Beauveriabassiana,two isolatesof Lecanicillium antillanum andone of Paecilomyces lilacinus, in addition to one isolate of Rhizopusstolonifer That grows with Lecanicillium antillanum inMycoparasitism relationship.The isolatedfungi wererecovered from Egyptian soil and from larvae of Spodopteralittoralis which found infected in a sugar beet field. Theseisolates were identified by conventional techniques in Mycological Center,Faculty of Science, Assiut University. Among these fungal species L. antillanumis a new record in Egypt. In addition, the activities of proteases, lipases,amylases and L-asparaginase of isolates fungi were recorded. The results showedthat, all isolates were active producers of extracellular hydrolytic enzymes.

Gamma ray induced effects on new species of streptormyces (aefo2) (hm775973.1g:302495616) isolated from egyptian soil

A new Streptomyces sp (AEFO2) isolated from Egyptian soil was exposed to increasing doses of gamma radiation up to 10 kG y and this isolate showed high antimicrobial activities against bacteria, yeast, and fungi. The lethal dose of studied isolate was 5KG y . Dose level of 3.5 kG y enhanced the antimicrobial activity, pigmentation, melanin production, utilization of carbon sources of this isolate and also increased their sodium chloride tolerance from 5 to 8 % either at first or second generation after irradiation process . Dose level 3.5 kG y showed decreasing of the amount of DNA in both first and second generations also.

Improved soil characteristics and wheat germination as influenced by inoculation of Nostoc kihlmani and Anabaena cylindrica

Many soils in Egypt have low nutrient content and poor structural stability. Herein, we have investigated the effects of inoculation of two nitrogen fixing cyanobacterial species (Nostoc kihlmani and Anabaena cylindrica), each alone and as a mixture on the chemical, physical and microstructure properties of the degraded soil, and on wheat growth 2 weeks of age. Scanning electron microscopy showed that inoculated soils had dense superficial network coatings of exopolysaccharides. Cyanobacterial inoculation increased significantly soil N, P, K and total organic carbon. Also, it increased the percentage of germination, root and shoot lengths, dry weights and the nutrient contents in the tested wheat. Differential improvement of the soil physico-chemical quality in a few weeks and effect of wheat germination could be explained by the effect of the cyanobacteria components. Nostoc kihlmani has higher contents of exopolysaccharides, indole acetic acid and cytokinins, whereas Anabaena cylindrica has higher nitrogenase activity and gibberellin content.

Screening of Inulinolytic Potentialities of some Fungi Isolated from Egyptian Soil

Screening of Inulinolytic Potentialities of some Fungi Isolated from Egyptian Soil

Calculation of gamma-ray mass attenuation coefficients of some Egyptian soil samples using Monte Carlo methods

Monte Carlo simulations, FLUKA and Geant4, were performed to study mass attenuation for various types of soil at 59.5, 356.5, 661.6, 1173.2 and 1332.5 keV photon energies. Appreciable variations are noted for all parameters by changing the photon energy and the chemical composition of the sample. The simulations parameters were compared with experimental data and the XCOM program. The simulations show that the calculated mass attenuation coefficient values were closer to experimental values better than those obtained theoretically using the XCOM database for the same soil samples. The results indicate that Geant4 and FLUKA can be applied to estimate mass attenuation for various biological materials at different energies. The Monte Carlo method may be employed to make additional calculations on the photon attenuation characteristics of different soil samples collected from other places.

The Role of Dissolved Organic Matter in Adsorbing Heavy Metals in Clay‐Rich Soils

Heavy metals (HMs) are toxic to human life and the environment when present in excessive concentrations. Therefore, determining the interactions of HMs with soils and dissolved organic matter (DOM) is essential to predict their fate. To find out the effect of DOM and soil properties (clay minerals, oxides, and bulk organic matter [OM]) on the uptake of Cu, Ni, and Zn, batch adsorption experiments were conducted using five soils sampled from Egypt. The sorption isotherms were well described by the initial mass (IM) isotherm model. The amount and timing of DOM addition was found to play a pivotal role in determining the affinity of the HMs for soil. When DOM and HMs were added simultaneously, the affinity of Cu decreased in Fe‐(hydr)oxide‐rich soils (by 7%) and increased in soils poor in Fe‐(hydr)oxide (by 6–10%). When DOM was added first, followed by HMs, the affinity of Cu strongly increased. In contrast, affinity of both Ni and Zn was enhanced (3–18%) in the presence of DOM, regardless of the timing of DOM addition. The difference is explained by Cu binding to the solid phase and DOM through strong inner‐sphere complexes, whereas Ni and Zn adsorbed predominantly through weaker electrostatic interactions. As a result, Cu was able to bind more strongly to previously adsorbed DOM on the solid phase in the case of smectite, while this effect was counteracted by the coating of available specific binding sites on Fe‐(hydr)oxides. The study has revealed that Egyptian soils hold great potential to remove HMs from aqueous solutions.

English

Several species of cyanobacteria has been recognized for its therapeutic value that can be used for treatment of malnutrition, cancer and viral infection. Many natural occurring cyanobacteria are known to produce toxins, for example, species of the genera Microcystis, Nodularia, Nostoc, Anabaena, Aphanizomenon, Cylindrospermopsis, and Planktothrix (Oscillatoria). Cyanotoxins are classified according to their mode of action in vertebrates as hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritants. Microcystin is a hepatotoxin which commonly found in Microcystis and it was found to be produced by other genera, including Anabaena, Nostoc, Nodularia, and Planktothrix. In the present study cyanobacteria strain isolated from Egyptian soil was purified, characterized and identified as Nostoc sp. and named Nostoc EGY. PCR-based techniques targeting the toxin biosynthesis genes were used verifying absence of toxic genes in the newly purified cyanobacteria. Cell lysate was prepared from the purified strain; the efficacy of this lysate to prevent hepatitis C virus (HCV) replication in vitro was proved qualitatively and quantitatively. Lysate prepared from isolated cyanobacteria after 10 and 25 days of cultivation was able to prevent replication of in vitro cultivated HCV. &nbsp; Key words: Hepatitis C, green algae, cyanobacteria, polymerase chain reaction.

Draft Genome Sequence of Frankia sp. Strain CcI6, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodule of Casuarina cunninghamiana

Members of the actinomycete genus Frankia form a nitrogen-fixing symbiosis with 8 different families of actinorhizal plants. We report a 5.57-Mbp draft genome sequence for Frankia sp. strain CcI6, a salt-tolerant nitrogen-fixing actinobacterium isolated from root nodules of Casurina cunninghamiana grown in Egyptian soils.

Economic Feasibility Study on the Use of Certain Amendments in the Bioremediation of Sewaged Soil

Cairo is now served by six large wastewater treatments works which produce significant quantities of sewage water. The preferred option is to use this in agriculture, particularly in reclaimed desert land which is inherently deficient in organic matter, nutrients and trace elements. The aim of this study was to assess economic feasibility of a novel biotechnology for remediation of sewaged soils on a long term basis. A field study was carried out at Abu-Rawash Sewage Farm where the soil has been irrigated with water sewage for 32 years and the site provides a possible model of the potential long-term effects of heavy metals and other pollutants on crops in the contaminated sewaged soils in Egypt. The high contaminated sewaged soil was bioremediated for 60 days with sole or combined remediative amendments in different treatments including uncultivated control, cultivated control, inoculation with AM, inoculation with a mixture of Thiobacillus thiooxidans & Thiobacillus ferrooxidans , treated with probentonite or treated with

Crop Water Requirements in Egypt Using Remote Sensing Techniques

The common Soil in Egypt is clay soil so common irrigation system is tradition surface irrigation with 60% irrigation efficiency. Agricultural sector consumes more than 80% of water resources under surface irrigation (tradition methods). In arid and semi-arid regions consumptive use is the best index for irrigation requirements. A large part of the irrigation water applied to farm land is consumed by Evapotranspiration (ET). Irrigation water consumption under each of the physical and climatic conditions for large scale will be easier with remote sensing techniques. In Egypt, Agricultural cycle is often tow agricultural seasons yearly; summer and winter. Common summer crops are Maize, Rice and Cotton while common winter crops are Clover and Wheat. Landsat8 bands 4 and 5 provide Red (R) and Near Infra-Red (NIR) measurements and it used to calculate Normalized Deference Vegetation Index (NDVI) and monitoring cultivated areas. The cultivated land area was 3,277,311 ha in August 2013. In this paper Kc = 2 * NDVI ? 0.2 represents the relation between crop coefficient (Kc) and NDVI. Kc and Reference evapotranspiration (ETo) used to estimate ETc in Egypt. The main objective of this paper is studying the potential crop Evapotranspiration in Egypt using remote sensing techniques.