Sucralose was developed as a low cost artificial sweetener that is nonmetabolizable in humans. Sucralose can withstand changes in pH and temperature and is not degraded by the wastewater treatment process. Since the molecule can withstand heat, acidification, and microbial degradation, it is accumulating in the environment and has been found in wastewater, estuaries, rivers, and the Gulf Stream. Environmental isolates were cultured in the presence of sucralose looking for potential sucralose metabolism or growth acceleration responses. Sucralose was found to be nonnutritive and demonstrated bacteriostatic effects on all six isolates. This growth inhibition was directly proportional to the concentration of sucralose exposure, and the amount of the growth inhibition appeared to be species-specific. The bacteriostatic effect may be due to a decrease in sucrose uptake by bacteria exposed to sucralose. We have determined that sucralose inhibits invertase and sucrose permease. These enzymes cannot catalyze hydrolysis or be effective in transmembrane transport of the sugar substitute. Current environmental concentrations should not have much of an effect on environmental bacteria since the bacteriostatic effect seems to be consecration based; however, as sucralose accumulates in the environment, we must consider it a contaminant, especially for microenvironments.

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.

No abstract

The gut microbiota is composed mainly of members from the phyla Bacteroides and Firmicutes. Others have shown a correlation of obesity with a reduction in the Bacteroides’ ability to grow normally and maintain their role in the gut. Sucralose is a ‘non‐metabolizable’ chlorinated sucrose derivative and the synthesized ingredient in the artificial sweetener Splenda®. Turbidity data obtained from active cultures showed a differential effect of sucralose on the growth curves between members of these Phyla. Sucralose had little effect on two Firmicutes, E. faecalis and C. sordellii, while there was a concentration dependent inhibition of growth of Bacteroides, B. fragilis and B. uniformis. Preliminary results of sucrase enzyme assays may demonstrate considerable competitive inhibition in the presence of sucralose. Furthermore, preliminary transport tests may have displayed differential results between the two phyla suggesting two putative means of metabolic inhibition that explain the reported growth curves. It must be considered that sucralose has the ability to alter gut flora composition by these differential metabolic findings and the negative health impacts from this imbalance must be addressed.

Sucralose is a low‐cost, zero‐calorie, artificial sweetener marketed under the brand name Splenda as an alternative to sugar. It is very stable and due to its ability to withstand the waste water treatment process, heat, acidification, and microbial degradation it is accumulating in the environment. Our objective was to find bacterial species exhibiting sucralose metabolism. Six bacterial species were isolated from sucralose‐exposed local surface waters. These microbes were isolated on sucralose –containing media and classified using traditional methods and 16srRNA gene sequencing. These isolates were cultured in TSB media amended with progressively greater concentrations of sucralose and their growth was measured using spectrophotometery. We refuted our original hypothesis, instead observing bacteriostatic and perhaps bacteriocidal effects on all six sucralose‐tolerant isolates. The efficiency of growth inhibition appeared species specific and directly proportional to the sucralose concentration. Present experiments suggest a mechanism for the bacteriostatic effect. These results will affect how sucralose is viewed to impact naturally occurring populations of environmental microbes.