Biodegradation of Anionic Surfactants (SDS) by Bacteria Isolated from Waste Water in Taif Governate

Abstract

Surfactants are synthetic chemicals which are utilized as crude material in cleanser production. Sodium dodecyl sulfate, (SDS) is an anionic surfactant that broadly utilized everywhere throughout the world. Which represent severe hazards effects on the ambient environment. Bacterial strains were isolated from different contaminated sites in Taif Governate (KSA) and screened for SDS degradation. Four bacterial isolates showed high degradation for SDS. The factors that affect the degradation rate of SDS were studied in this work. The selected isolates that can degrade SDS were found to degrade SDS at pH 7-7.5. The optimum temperature was at 30ºC and optimum agitation was at 150 rpm. The degree of SDS degradation was increased when the bacterial isolates were combined together. It was found that the four isolates were able to degrade different concentration of SDS until 4%. Different incubation time was studied and it appear that the degradation begin after 24 hrs. but the optimum degradation  occur after 15 days. Also different inoculum size was tested. These isolates were physiologically and molecularly identified. These potential strains were biochemically characterized as Gram-negative bacteria. Subsequently, partial sequence of 16S rRNA identified these strains as Pseudomonas aeruginosa (H), Pseudomonas otitidis (A3), Enterobacter cloacae (A5) and Klebsiella aerogenes (A6). This work reveals that the Pseudomonas aeruginosa (H), possess greater potential to degrade SDS when compared with other bacterial strains.