Microbial Degradation of Sodium lauryl sulfate Using Bacterial Consortium Isolated from Coastline of Alexandria City

Abstract

Sodium lauryl sulfate (SLS) is an anionic surfactant that may easily find its way to seawater through domestic and industrial wastewater discharge. The current study was suggested to investigate its fate in relation to the ability of heterotrophic bacteria isolated from samples to degrade SLS surfactant. In addition, the different factors affecting the biodegradation process. Out of nine dominant marine bacteria, only three were able to degrade SLS successfully. They were characterized throughout morphological, biochemical and physiological features as; Enterobacter gergoviae , Enterobacter cloacae and Bacillus alvei. Our data confirmed that the biodegradability of consortium consisting of E. gergoviae , E .cloacae and B. alvei combination was more effective than that of the individuals. The increase in inoculum size, support the increase in the biodegradation. The 30 o C as an incubation temperature was the most effective temperature (98% biodegradation). The pH 9 was the optimum for the growth of consortium (E. gergoviae , E. cloacae and B. alvei) and consequently for biodegradation rate (96%). The pH level 7 was more or less near to optimum with biodegradation percentage (89.2%). Glucose as a carbon source and casein as a nitrogen source improved the biodegradation process to 91.9% and 90.3% respectively. The biodegradation percentages showed an inverse relationship between the increase in SLS mass and the extent of its degradation. Under these growth conditions a complete degradation of 1000 ppm SLS biomass was achieved with biodegradation percentage (45.5%). Such findings contribute to a better understanding the fate of the SLS in the aquatic environment. Keywords: Biodegradation , sodium lauryl sulfate (SLS), bacterial consortium