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Biotranformation of Selected Pollutants Using Biofilm Forming Bacteria

Thesis Info

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Author

Tahir, Uruj

Program

PhD

Institute

Fatima Jinnah Women University

City

Rawalpindi

Province

Punjab

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Environmental Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/11872/1/uruj%20tahir%20envir%20sci%202019%20fjwu%20rwp%20prr.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676724536297

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Environmental contamination due to improper dumping of industrial effluents and its toxicological manifestations has been recognized as major cause of public health risks, especially in developing countries. It has urged the scientific community to focus on various approaches to remedify their impacts.Keeping in view, the costs and generation of toxic byproducts related to conventional remediation strategies, there is a continuous need to look for environmentally safe technologies. Biological techniques (bioremediation) using microbial biomass and their biomolecules/products offer better treatment of contaminants compared to physical and chemical methods. Such potentials of biofilm forming bacteria and their biopolymers were investigated in present work. Bacteria from biofilm samples were isolated and screened for biofilm formation and decolorization of chemically variable dyes. All bacterial isolates were Gram negative, facultative anaerobes and mesophiles. They conferred resistance to multiple heavy metals including cadmium (100-1000 mg L-1), chromium (7001000 mg L-1), copper (600-1000 mg L-1), lead (1000 mg L-1), iron (1000 mg L-1) and nickel (200-600 mg L-1). Selected isolates with potentials to degrade/transform xenobiotic compounds were characterized at molecular level and identified as Staphylococcus sp. MB377, Bacillus subtilis MB378, Klebsiella oxytoca MB381 and Klebsiella pneumoniae MB398.Bacterial isolates showed the capability of decolorizing and degrading different dyes (Eriochrome black T, Congo red, Malachite green) in the presence and absence of glucose. Bacillus subtilis MB378 was most efficient in degrading these dyes up to 65-90% in presence of glucose. Optimum conditions for decolorization of Congo red dye were pH 5 (Klebsiella pneumoniae MB398), Eriochrome black T dye pH 8 (Bacillus subtilis MB378) and Malachite green dye pH 9 (MB392). While highest decolorization rates of Congo red dye were observed at 37˚C (Klebsiella pneumoniae MB398), Eriochrome black T dye at 30˚C (Bacillus subtilis MB378) and Malachite green dye at 30˚C (MB392), respectively. UV-VIS spectrophotometric & FTIR analysis, high performance liquid chromatography (HPLC) and gas chromatography (GCMS) further confirmed the possible degradation/transformation of dye molecules into respective metabolites.Assessment of simultaneous removal of dye and selected metals by biofilm forming bacteria showed efficient decolorization of Malachite green dye in presence of cadmium, copper and xxiv chromium (up to 79.65 & 88.07%, 79.35 & 93.18%, and 81.63 & 90.32%) by Staphylococcus sp. MB377 and Bacillus subtilis MB378, compared to individual dye molecules. Bioaccumulation yield of copper in combination with Malachite green dye was 30.88 mg L-1 (Staphylococcus sp. MB377), 31.22 mg L-1 (Bacillus subtilis MB378), while for chromium it was 29.88 mg L-1 (Bacillus subtilis MB378). Maximum chemotactic indices were recorded in the presence of glucose for Congo red by MB387 (1.37), Methyl orange by MB391 (0.97), Malachite green by MB391 (0.87) and Eriochrome black T by MB377 (0.74). Highest chemotactic potentials of Klebsiella oxytoca MB381 towards chromium (83.14), Staphylococcus sp. MB377 towards lead (81.23), MB392 towards cadmium (0.74) and Staphylococcus sp. MB377 towards copper (0.47) were recorded through capillary assay in the presence of glucose, while chemotactic response towards dyes and metals declined in the absence of glucose. Biopolymeric substances (EPS) were rich in carbohydrate contents and also harbored fairly good antimicrobial activities against target bacteria with inhibition zones ranging between 0.8-1.91 cm. FTIR spectroscopic analysis showed that these polysaccharides were comprised of proteins, carbohydrates, alkyl halides, nucleic acids, various hydrophilic and hydrophobic functional groups. SEM and XRD analysis revealed compact and crystalline nature of EPS. EPS from Staphylococcus sp. MB377, Klebsiella oxytoca MB381 and Klebsiella pneumoniae MB398 formed 67.71, 61.25 and 60.46% stable emulsions. EPS from Klebsiella pneumoniae MB398 gave highest emulsion retention values for Canola oil (1.330±0.045), Kerosene oil (1.261±0.251) and n-Hexane (0.794±0.120). EPS from Bacillus subtilis MB378 removed 96.09% of cadmium in combination with Malachite green, with an adsorption rate of 0.98 mg g-1. While 90.86% of copper removal in the presence of Malachite green dye was observed for EPS from MB392, compared to individual metal ions. EPS from Staphylococcus sp. MB377 removed 85.10 and 84.76% of Malachite green in combination with cadmium and chromium compared to dye molecules alone. FTIR spectra further confirmed that the reactions and complexation of dye in presence of metals with charged or ionizable functional groups of EPS had facilitated their adsorption and accumulation on to the surfaces of EPS. Complete genome sequencing of Staphylococcus sp. MB377 and Bacillus subtilis MB378 showed that each genome possessed significantly diverse structural and functional features. Both these strains had multiple genes involved in biofilm formation, adhesion, xxv exopolysaccharide production and chemotactic responses. Genes for metal resistance (Cd, Cr, Cd/Zn/Co, Cu) and reduction of arsenic were also annotated in the genomes of Staphylococcus sp. MB377 and Bacillus subtilis MB378, respectively along with multidrug efflux and transporting systems. These strains also possessed wide range of metabolic activities for effective catabolism and detoxification of xenobiotic compounds. Stress induced/response proteins were indicative of defense mechanisms and ability of bacteria to survive in diverse environmental conditions. Annotated genes encoding for various enzymes (dioxygenases, acylphosphatases, nitroreductases, tautomerase, laccase-like multicopper oxidase and oxidoreductases) indicated the potentials of these strains for utilizing and degrading different aromatic compounds and dyes.The diversity and potential of biofilm forming bacteria to adapt in diverse environmental conditions was recognized in present study. The results further supported present bacteria and their biomolecules as most potential/effective candidates for the remediation of polluted sites.
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سید قطب

سید قطب
اخوان المسلمین کے مشہور رہنما سید قطب اور ان کے تین ساتھیوں کو ناصر کے خلاف سازش کے جرم میں پھانسی دے دی گئی اور دوسرے لیڈروں کو مختلف المیعاد قید کی سزائیں دی گئیں ہیں جن میں بعض عورتیں بھی ہیں، یہ کوئی خلاف توقع خبر نہیں، ناصر مختلف حیلوں سے اخوان کو ختم کردینے پر تل گئے ہیں، حجاز میں ان پر ناصر کے وحشیانہ مظالم کے جو واقعات معلوم ہوئے تھے، ان کو سن کر الجزائر کے مسلمانوں پر فرانس کے مظالم کی یاد تازہ ہوگئی تھی، یہ وہ دینی شخصیتیں تھیں، جن کے بارے میں کسی سازش کا تصور بھی نہیں کیا جاسکتا لیکن اعلا کلمۃ اﷲ کی تاریخ نیا واقعہ نہیں ہے، بہت سے اصحاب دعوت و عزیمت کو اس راہ سے گزرنا پڑا ہے، گویہ واقعہ ساری دنیائے اسلام کے لیے المناک ہے، لیکن سید قطب اور ان کے رفقا، شہید فی سبیل اﷲ کے درجہ عالی پر سرفراز ہوئے اور دعوت و عزیمت کی تاریخ میں ان کا نام ہمیشہ کے لیے روشن ہوگیا، اﷲ تعالیٰ ان شہدائے حق پر اپنی رحمت کے پھول برسائے۔ (شاہ معین الدین ندوی، ستمبر ۱۹۶۶ء)

 

أمير الشعراء أحمد شوقي: نثره الفني ومنهجه

It is very clear that Ahmad shoqi was titled as king of modern Arabic poetry due to his unforgettable literary deeds towards it. Apart it all, his good struggle toward Arabic prose were ignored in his life, because of the prose was not his field to be tried in and it has its own experts. Some of these experts collected his prose and compiled it in a huge encyclopedia of his literary works named “al mosoa al shoqia” (الشوقية الموسوعة). This article also discussed his literary prosaic struggles, his methodology which he acquired and the deficiencies which were pointed out by critics. Adding more, the feature of the prose are also drawn in.

Study of Soft X-Rays from Depleted Uranium Assisted Pre-Ionized Plasma in a Low Energy Mather Type Plasma Focus Device

This thesis describes the experimental investigations of the soft X-ray emission and the plasma dynamics in a Mather type plasma focus device operated in different gases (Neon, Helium, Deuterium, Neon+Helium) by changing different parameters like charging voltage, capacitor bank energy, discharge current, anode shape, gas pressure and influence of preionization. The objectives of the studies are to enhance soft X-ray emission. The Rogowski coil, high voltage probe, PIN diodes and pinhole camera masked with appropriate absorption filters are used for diagnostics. Specifically attention is paid to tailor the radiation in different energy windows i.e. 1− 1.56 keV and 4−8.33 keV. A single 12.5 μF capacitor charged at 19-23 kV (2.25-3.3 kJ), with a field distortion type sparkgap as switch is used to transfer the energy to the system. In the first experiment, the effect of preionization caused by depleted uranium (92U238) on soft X-ray and total X-ray emission is investigated by varying the neon gas pressure with and without preionization. The X-ray yield and pinhole images are found strongly influenced by the preionization and the pressure of the working gas. The soft X-ray yield of 82.5 ± 4.0 J in 1.3–1.56 keV energy window is obtained with preionization of neon gas at the optimum pressure, leading to the conversion efficiency of 2.5% of the stored energy. The total X-ray yield with preionization is 195 ± 9.0 J in 4π geometry measured at the optimum pressure giving conversion efficiency of 5.9%. The time integrated images indicate the broadening of X-ray emission zone with preionization. The second experiment is performed with helium as filling gas. The highest soft X-ray yield of 0.25 ± 0.01 J is obtained without preionization, which increases to 0.50 ± 0.02 J with preionization at optimum pressure. The total X-ray yield 1.50 ± 0.07 J without preionization, is enhanced to 2.44 ± 0.11 J with preionization. The plasma focus duration has been increased with preionization conforming enhancement and improvement in X-ray. This has also been conformed by the symmetric and enlarges pinch images with preionization.