الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 134 |  |  |
| | | from | 134 | | |
Abstract
Phenols are very soluble in water; as a result, they can pollute a massive volume of fresh water, wastewater, groundwater, oceans, and soil, negatively affecting plant germination and animal and human health. For the detoxification and bioremediation of phenol in wastewater, phenol bio-degradation process using novel bacterial species isolated from different sources was investigated. The samples from different sources such as sewage sludge (SS), effluent of ceramic factories (C), petrochemical (P), the pulp paper mill (M), crude oil (O) and sewage water (S) have been investigated. The samples from each source were collected, and bacteria in SS, C, P, M, O and S contents were cultured in the mineral salt agar (MSA) containing phenol (500 mg/L). The colonies were recovered from each tested sample. Eight isolates were successfully isolated and characterization of phenol-degrading-bacteria from the effluent of ceramic factories (C2), petrochemical (P4), the pulp paper mill (M4), crude oil (O3), sewage water (S3), and sewage sludge (SS3, SS10, & SS18). These eight isolates were characterized depending on some morphological, physiological, and biochemical characteristics were performed. The characteristics of three only bacterial properties, 16S rDNA sequencing, similarities, GenBank accession number, and phylogenetic analysis showed that strains SS3, SS10, and SS18 were Pseudomonas aeruginosa, Klebsiella pneumoniae, and Klebsiella variicola, respectively. Among the eight higher phenol degrading isolates, two isolates can tolerate up to 1500 ppm of phenol concentrations, grow and degrade 94% of phenol within 72 hrs. The optimum temperature and pH conditions were 35 0C and 7, respectively. The yeast extract and ammonium chloride are the best organic and inorganic nitrogen source for the growth and degradation of phenol. The isolate P4 was efficient in removing above 90% of the initial 1000 mg/L phenol within 48 hrs. and had a tolerance of phenol concentration as high as 1500 mg/L. P. aeruginosa, K. pneumoniae, and K. variicola were able to degrade 1000 mg/L phenol in the mineral salt medium. The bacterial strains from sewage sludge were efficient in removing 71.70 and 74.67% of phenol at 1000 mg/L within three days and could tolerate high phenol concentrations (2000 mg/L). The findings showed that P. aeruginosa, K. pneumoniae, and K. variicola could potentially treat phenolic water. All soybean and faba bean seeds were germinated after being treated with 250, 500, 750, and 1000 mg/L phenol in a mineral salt medium inoculated with these strains. The highest maximum phenol removal and detoxification rates were P. aeruginosa and K. variicola. These strains has the ability to decompose and detoxify phenol from industrial wastewater with high phenol levels and bioremediating phenol-contaminated soils. These results indicated that presumptive Pseudomonas sp. (SS3) possesses a promising potential in treating phenolic wastewater.