الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The strong colour of the textile waste water is the most serious problem of the textile waste effluent. Disposal of these wastes into receiving water causing many damages to the environment. Dyes may significantly affect photosynthetic activity in aquatic habitat because of reduced light penetration and may also be toxic to some aquatic life due to the presence of some aromatics, metals, chlorides and other toxic compounds. The present study was carried out to degrade the textile dyes by using bacteria isolated from the industrial wastewater effluent. Two different bacterial isolate of, Bacillus sp., Escherichia sp. and were isolated from textile dye effluent and used for the degradation of the synthetic dye study. Applying such bacterial cells in the degradation developed the eco-friendly and cost effective biological methods for the treatment of industrial effluent instead of the highly costing and highly polluting chemical and physical methods.
The results obtained are summarized in the following points :
1- The isolation procedure resulted in the successful selection of 16 bacterial isolates have the capability of the decolorization of the four used synthetic dyes when grown on LB media. The isolates were isolated from the textile industry wastewater effluent.
2- In the screening experiement, chose just the bacterial isolates that showed the highest clear zone and the ability degrade all the different dyes. They were just five bacterial isolates B2, BK1, BK2, Y2 and B4.
3- On different liquid media MSM 1 - MSM 2 - MSM 3 – MSM 4 and LB compared the decolorization % of Remazol Blue which is the most complex dye by the 5 choosen bacterial isolates. The isolates B2 and BK1 were the most promising bacterial isolates and MSM 3 proved to be the best media to support the degradation of Remazol Blue.
4- Using 16S rDNA gene sequence analysis, Isolates B2 and BK1 were identified genotypically, B2 showed 99% similarity to genus Bacillus. It was affiliated to the genus Bacillus and was designed as Bacillus sp. G13, while BK1 was affiliated to the genus Escherichia and was designed as Escherichia sp. NG188. This was followed by phenotypic characterization using NA media. Some physiological and biochemical characterization using VITEK 2 system was conducted as well.
5- Growth pattern of Bacillus sp. G13 and Escherichia sp. NG188 showed that cells grow exponentially till 18h then entered the stationary phase of growth where cells almost remained constant.
6- The time course of the degradation of the RB dye was studied by Bacillus sp. G13 and Escherichia sp. NG188 at 37°C and comparing the growth of cells with and without the dye, maximum dye degradation was after 60h and 54h, respectively 7- Effect of aeration is considered a very good parameter that controls the degradation of dye, it was studied under static and shaked conditions in MSM 3 media with pH value (7) using 5% inoculum size and incubated for 3 days, The static conditions were much better the shaking in degradation of RB by Bacillus sp. G13 and Escherichia sp. NG188, they showed almost 2.6 and 3.1 fold increase, respectively, compared to that incubated under shaked conditions.
8- Temperature is an important factor affecting growth and metabolic activity of microorganisms, 40°C was found to be the optimum temperature when compared to 30°C, 37°C and 45°C and achieved the highest decolorization% as they could degrade 63% and 59% by Bacillus sp. G13 and Escherichia sp. NG188, respectively.
9- Studying the tolerability of Bacillus sp. G13 and Escherichia sp. NG188 to the highest concentration (50– 1000) mg/L of RB using MSM 3 media with pH value (7) using 5% inoculum size was found to be high in the lower concentrations after 3 days of incubation at 40°C for the both strains.
10- The optimum inoculum size for the RB degradation was found to be 5 % when compared with 1, 3, 7 and 9 % using MSM 3 medium with pH value (7) as they could degrade 63% and 59% by Bacillus sp. G13 and Escherichia sp. NG188, respectively.
11- pH value effect was studied to identify the optimum pH value support degradation of dye using MSM 3 with different pH value (6, 7, 8, 9, 10, 11 and 12 ) using 5% inoculum size and incubated for 3 days at 40°C pH8 was the optimum for Bacillus sp. G13 and Escherichia sp. NG188 and achieved the highest decolourization% 70 % and 72% ,respectively.
12- Consortium between Bacillus sp. G13 and Escherichia sp. NG188 was not found to be valuable as it had an antagonistic effect on Bacillus sp. G13 and it had no effect on Escherichia sp. NG188 as the consortium recorded 70 % decolorization, while Bacillus sp. G13 recorded 72% and Escherichia sp. NG188 recorded 70 %.
13- Special concern was given to determine nutritional and cultivation requirements to further increasing in degradation of RB dye of Bacillus sp. G13 and Escherichia sp. NG188. Hence the influence of nutritional factors on dye degradation via plackett-Burman statistical design was investigated. On the basis of the calculated t-values, p-values and confidence level (significant level, %): Glucose and dye concentration for Bacillus sp. G13 while for Escherichia sp. NG188 were found to be K2HPO4.