Resumo

KEHINDE, I.T; ENIOLA  e  OLAYEMI, Albert B.. Linear Alkylbenzene Sulfonate tolerance in bacteria isolated from sediment of tropical water bodies polluted with detergents. Rev. biol. trop [online]. 2008, vol.56, n.4, pp.1595-1601. ISSN 0034-7744.

The discharge of untreated detergent-bearing waste introduces linear alkylbenzene sulfonates (LAS) to the aquatic environment. The surfactant persists in some streams and rivers in Nigeria, some is adsorbed to suspended materials and end in the sediment of the receiving water bodies. In this study, bacteria isolated from sediments of some tropical detergent-effluent-polluted streams were tested for tolerance to LAS using the media dilution technique. LAS-tolerance was indicated by growth of the bacteria in the presence of the surfactant. The pH, concentrations of surfactant, population of heterotrophic bacteria and population of LAS-tolerant bacteria in the sediments were determined. A direct relationship (r= 0.9124) was found between the alkaline conditions (pH= 8.2-12.0) and high surfactant concentrations (45-132 mg/g) in the sediment. The sediments harboured a high population and a wide variety of bacteria; the populations of viable heterotrophic bacteria (vHB: 2.9×10⁵ to 1.2×10⁷ cfu/g) and LAS tolerant bacteria (LTB: 1.5×10⁴ to 1.2×10⁶ cfu/g) had a direct relationship (r= 0.9500). An inverse relationship resulted between each of them and the concentration of surfactant in the sediment, r_{vHB/ LAS} = -0.9303 and r_{LTB/ LAS} = -0.9143, respectively. Twelve bacteria species were isolated from the sediment: Alcaligenes odorans, Bacillus subtilis, Burkholderia cepacia, Citrobacter freundii, Citrobacter diversus, Escherichia coli, Micrococcus luteus, Micrococcus albus, Pseudomonas putida, Pseudomonas stutzeri, Staphylococcus aureus and Streptococcus faecalis. Most of them were adapted to the surfactant with their maximum acceptable concentrations ranging between 0.03 and >1.0% (w/v). The sediments could serve as source of adapted organisms which can be used in bio-treatment of LAS-bearing waste. Rev. Biol. Trop. 56 (4):7-15. Epub 2008 December 12.

Palavras-chave : LAS; surfactant; tolerance; detergent; effluent.

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