الفهرس 
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Abstract
Over the last few decades, increasing globalization, urbanization, and industrialization have causes different environmental pollution. Water pollution occurs when pollutants (particles, chemicals or substances that make water contaminated) are discharged directly or indirectly into water bodies without enough treatment. Wastes from industry serve as major sources for all water pollutants. Wastewater containing a number of pollutants one of the important classes of these pollutants are phenol once they enter the water it is no longer good and sometimes difficult to treat. Accumulation of phenolic compounds wastewater creates not only environmental pollution, but also an aesthetic problems. As regulations are becoming even more stringent, there is an urgent need for technically feasible and cost-effective treatment methods.
The main objective of the present study was to find a suitable biological treatment for biodegradation phenol which discharged from textile, petrochemicals, leather, cosmetics, and pharmaceutical industries.
Bioremediation of environmental pollutants relies on the pollutant degrading capabilities of naturally occurring microbial consortia in which bacteria play central role. Microbial degradation of phenol have significant potential to address this problem due to their environmentally-friendly, inexpensive nature, and also because they do not produce large quantities of sludge. In addition, bacteria have many other advantages such as a fast growth rate and high hydraulic retention time, and thus they could be efficient in treating high- strength organic wastewaters.
The present study was carried out under aerobic condition; the strains isolated from different locations of some local industrial outlets which contaminate area by phenol in Alexandria, Egypt, were screened for the ability to biodegrade phenol. About 9 bacterial strains were isolated and the bacterial strains given a prefix of ”A” from A1 to A9 and among them with the strongest degradation ability were able to degrade phenol were 4 strains. After several experiments the most efficient isolate chosen were A2 and A7.
The 16S rRNA sequencing of the most efficient bacterial strain A2 showed 99% similarity to Stenotrophomonas maltophilia sp. and A7 showed 99% similarity to Pseudomonas sp.
The Effect of various parameters such as phenol concentrations, pH, temperature, shaking and static conditions and contact time, were noted affect the growth and degradation potential of the most effected isolated bacterial strains that able to degrade selected phenol.
Results showed that optimum conditions of Stenotrophomonas maltophilia sp. A2, Pseudomonas sp. A7 , and consortium of both strain A2 And A7 for degradation of phenol where; the initial phenol concentration was investigated 1000 mg/L, The optimum temperature is 30°C , pH 7 and at the static conditions for 24 hr incubation time. The degradation percentage of Stenotrophomonas maltophilia sp. A2 was improved from 88% to reach 92.5 %. The degradation of Pseudomonas sp improves from 86.32 % to 91.27 % and finally the degradation percentage of the consortium improved from 87.2 % to 91.87 %.