This paper study the ability of Enterobacter cloacae for degrading crude oil in contaminated water. Six isolates of E. cloacae were isolated from hydrocarbon contaminated soil and water of different sites. The isolate E. cloacae E1 showed the highest emulsification index (E24%) reached 62% thus it was chosen for further study. Biosurfactant produced by E. cloacae E1 reduced the surface tension of the medium from 64 to 36 mN/m. pH range 6.5 – 7 and temperature range 30˚C - 35˚C were the optimal conditions for maximum degradation. After 30 days of incubation, E. cloacae E1 degraded 70.00 ± 0.40% of the crude oil. GC-MS analysis revealed that E. cloacae E1 was able to degrade aromatic compounds. This study proved that E. cloacae E1 consider being an efficient in crude oil degradation.
Abstract
Objective of this research focused on testing the impact of internal corporate governance instruments in the management of working capital and the reflection of each of them on the Firm performance. For this purpose, four main hypotheses was formulated, the first, pointed out its results to a significant effect for each of corporate major shareholders ownership and Board of Directors size on the net working capital and their association with a positive relation. The second, explained a significant effect of net working capital on the economic value added, and their link inverse relationship, while the third, explored a significant effect for each of the corporate major shareholders ownershi
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In this paper, estimation of system reliability of the multi-components in stress-strength model R(s,k) is considered, when the stress and strength are independent random variables and follows the Exponentiated Weibull Distribution (EWD) with known first shape parameter θ and, the second shape parameter α is unknown using different estimation methods. Comparisons among the proposed estimators through Monte Carlo simulation technique were made depend on mean squared error (MSE) criteria
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