Isolation and characterization of synthetic detergent- degraders from wastewater

The biodegradability of the principal component of synthetic detergent products known as linear alkylbenzene sulphonate (LAS) has been contentious, hence the need to evaluate its primary biodegradation by indigenous microorganisms in wastewater ecosystem. The native microbial consortium of a wastewater ecosystem found to utilize detergent components were characterized using standard and conventional methods. The organisms identified were Enterococcus majodoratus, Klebsiella liquefasciens, Enterobacter liquefasciens, Klebsiella aerogenes, Escherichia coli, Enterobacter agglomerans, Staphylococcus albus, Pseudomonas aeruginosa, Proteus sp., Klebsiella oxytoca, Brevibacterium sp., Myceliophthora thermophila, Geomyces sp., Alternaria alternata, Verticillium alboatrum, Aspergillus flavus, Trichoderma sp. and Aspergillus oryzae. Alkaline pH and mesophilic temperature range (33.9 – 34.3C) was found to be supportive of the metabolic activities of the detergent-degraders in the tropical wastewater ecosystem. The bacterial detergent-degraders were more of gram-negative than gram-positive. Fungal detergent-degrader activities were abruptly terminated as the pH shifted to the alkaline range probably due to production of alkaline intermediates. The biodegradation of the synthetic detergent components that occurs in wastewaters, sewage treatment plants and in the ultimate open-water receiving ecosystems is primarily the result of microbial activities.