Differential Bacteriostatic Effects of Sucralose on Various Species of Environmental Bacteria

Sucralose was developed as a low-cost artificial sweetener that is nonmetabolizable and can withstand changes in pH and temperature. It is not degraded by the wastewater treatment process and thus has been found in waste water, estuaries, rivers and the Gulf Stream. Since the molecule can withstand heat, acidification, and microbial degradation, it is accumulating in the environment. The highest concentration of environmental sucralose detected to date is 300？ng/L. Our lab has isolated six bacterial species from areas that have been exposed to sucralose. We then cultured these isolates in the presence of sucralose looking for potential sucralose metabolism or growth acceleration. Instead we found something very interesting, bacteriostatic effects exhibited on all six isolates. This inhibition was directly proportional to the concentration of sucralose exposure. The efficiency of the growth inhibition seemed to be species specific, with various concentrations inhibiting each organism differently. 1. Introduction An unexpected contaminant in our aquatic and costal environments is artificial sweeteners [1]. Due to the human inability to metabolize them, they are passed on to the environment via human excrement. Naturally the highest concentration of artificial sweetener contaminants is in waste water treatment plants’ reservoirs. Artificial sweeteners such as saccharin and cyclamates are detected in lower concentrations and are found 90% degraded by the wastewater treatment process. Sucralose, however, is found in higher concentrations and is minimally degraded [2]. Degradation only occurs to a limited extent during hydrolysis, ozonation, and microbial processes indicating that breakdown of sucralose will likely be slow and incomplete leading to accumulation of sucralose in surface waters [3]. This indicates that conventional waste water treatment is ineffective at degrading sucralose [2]. From wastewater facilities the pollutants are dumped into public waterways, and sucralose has been detected in rivers in North Carolina, in the Gulf Stream, and even in the waters of the Florida Keys [4]. Also for the first time scientists are detecting sucralose in the USA inland surface waters [2]. Artificial sweeteners have been considered contaminants by environmental scientists for a short time because artificial sweeteners are water contaminants that are highly specific to wastewater [1]. Most artificial sweeteners are either partially or completely broken down due to the waste water treatment process using high temperatures, changes in pH, and constant filtration.