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Abstract: Urease was immobilized on commercial cotton and commercial cotton activated with glutaraldehyde. The kinetic of urea hydrolysis by free and immobilized urease was studied as a function of pH, temperature and time of hydrolysis. High concentration of ammonia was released at pH 10.0 for free enzyme (0.097 mg/mL) and urease immobilized on cotton (0.092 mg/mL) and pH 4.0 for enzyme, immobilized on activated commercial cotton (0.083 mg/mL). High concentration of ammonia was released at 30 °C for free enzyme (0.006 mg/mL), 25 °C for urease immobilized on cotton (0.043 mg/mL) and urease immobilized on cotton activated with glutaraldehyde (0.015 mg/mL). High concentration of ammonia was released after 10 minutes for free enzyme (0.0016 mg/mL), 60 minutes for inactivated (0.043 mg/mL) and for activated cotton (0.015 mg/ml). The result show that immobilized urease is less effective than the free enzyme and is more active in acid medium than the basic medium. Keywords: Urease, cotton, immobilization, glutaraldehyde, hydrolysis. |
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Abstract: A pot experiment was conducted to study the effects of conjunctive use of saline and fresh water on the growth and biomass of cotton crop and to observe varietal variability for salinity tolerance and ion contents of cotton genotypes. Four cotton genotypes (Sindh-1, BT-121, CRISS-494, CRISS-588) were irrigated with four treatments, C1 (control+ tape water), C2 (EC 4.0 dS m-1, throughout growth period), ( (six irrigation with C2 + six irrigation with C1), C3 (EC 8.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C3), (six irrigation C3+ six irrigation C1), C4 (EC 12.0 dS m-1, throughout growth period), (six irrigation C1+ six irrigation C4). The results showed that highest fresh biomass, plant height, number of leaves plant-1, number of bolls and boll weight was obtained in the treatment where tape water was used. Whereas, these parameters were decrease significantly with the increasing salinity levels from 4 to 12 dS m-1 and when saline water was applied continuously throughout growth period. The cotton genotypes Sindh-1 and Bt-21 performed well under conjunctive use of saline and fresh water with maximum values in compare to genotypes CRIS 494 and 588. The Na+ and Cl- accumulation in cotton leaves and in soil significantly increased with rising EC levels of irrigation water. However, Na+ and Cl- contents were found more in CRIS 494 and CRIS 588 than Sindh-1 and Bt1. It is concluded that Sindh-1 and Bt-121 may be cultivated in saline areas with alternate irrigation. Keywords: Saline water, conjunctive use, Cotton genotypes growth. |
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Abstract: A field experiment was conducted at Sindh Agriculture University Tandojam during the year 2015-16, aiming to investigate the response of turnip crop to various salinity levels of irrigation. The experiment was placed applying randomized complete block design (RCBD) with four different treatments i.e. Freshwater (I1), ECw with 2.5, 3 and ECw3.5 dS m-1 (I2, I3 and I4) respectively replicated thrice. The results for experiment placed revealed an average increase in soil ECe 0.09, 0.17, 0.26 and 0.38 dS m-1 under I1, I2, I3 and I4 respectively. An decrease in dry density (g cm-3) of soil profile, decrease in pH 0.19, 0.38, 0.5 and 0.84 in treatments I1, I2, I3 and I4 respectively and an decrease in agronomical data i.e. weight and diameter were also observed with an increase in ECw by the water being irrigated. Crop water productivity with 5.83, 4.35, 2.97 and 1.85 kg m-3 for treatmentsI1, I2, I3 and I4 respectively also decreased with an increase in ECw and Nacl. Average yield of 19.27, 14.37, 9.83 and 6.12 kg was obtained with applied treatments i.e. I1, I2, I3 and I4 respectively, thus a decrease in yield with 25.45%, 31.60% and 37.72% with treatments I2, I3 and I4 was observed when compared as treated by freshwater (I1). Therefore farmers can use irrigation water having ECw 3.5 dS m-1 for the turnip crop at reduction of 37.72% (approximately). Keywords: Irrigating water qualities, Furrow irrigation method, Turnip growth, Turnip yield, Water productivity. |
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Abstract: In consideration of the issue related to the poor performance of asphalt pavements against climatic stresses and the need to contribute to the solution of the ever-increasing environmental hazards, the study paved the way for the recognition of using waste tyre as an asphalt binder modifier for pavement construction to settle the rising issue on waste disposal, while also improving the pavement properties. A series of experiments were conducted using different levels of recycled tyre rubber (RTR) substituted in asphalt binder. Marshall Stability and Marshall Immersion test were selected as basis to evaluate the properties. The results of experiments conducted on Marshall Mix samples demonstrated that stability of the pavements increased in a quadratic fashion with increasing fraction of RTR, and were found to be maximum at 10% rubber in asphalt mix, contributing an average enhancement of approximately 35% as compared to the conventional pavements. Furthermore, retained stability of samples was found to increase with increasing ratio of rubber substituted, making it a suitable candidate for modification in highly humid and rainy areas. Keywords: Recycle tyre rubber (RTR), polymer modified asphalt, asphalt pavement. |
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Abstract: The production of biodiesel from vegetable oils using eco-friendly processes is a hot topic actually. These processes are based on enzymatic biocatalysts, namely lipases, and present many advantages over classical processes i.e. they do not require the use of sodium hydroxide, nor huge quantities of water. Lipases are widespread in nature, being produced by many microorganisms. However, fungal lipases have benefits over bacterial lipases due to their low cost of production, thermal and pH stability, substrate specificity and activity in organic solvents. These low cost production processes rely, most of the time, on solid-state fermentation (SSF). The aim of this research was to select microorganisms for their ability to secrete lipolytic enzymes and to grow on a solid support compatible with SSF. Thirty-five yeast and mold strains were tested in term of growth rate and extracellular lipase production. Different solid support such as vermiculite, crushed wheat husk, cacao seed-husk and carbon sources such as soy oil, sunflower oil, olive oil or sucrose were also tested for their ability to support cell growth and lipase production. Keywords: Lipase production, agroindustrialsolid residual, growth medium, Aspergillusniger, enzyme. |