Screening of lactic acid bacteria strains for their ability to bind phthalate monoesters in vitro and the binding characteristics

In the present study, thirty lactic acid bacteria (LAB) strains were first screened for their ability to remove mono-n-butyl phthalate (MBP) in vitro, one representative of phthalate monoesters (PMEs), from the aqueous solution. Three Lactobacillus plantarum and two L. fermentum strains removed more than 25% MBP and were selected for further investigation of the binding characteristics. Consequently, five LAB strains were resistant to MBP, and the binding ability depends on initial MBP and bacterial cell concentrations. In particular, the removal was a fast and reversible process, and pH plays a major role in the binding capability. Both heat-treated and acid-treated bacteria were capable of removing the MBP, indicating the binding, not metabolism, is the mechanism by which MBP is removed from the aqueous solution. Acid treatment can increase the binding ability of LAB and also enhance the stability of MBP-LAB complex. In addition, these LAB strains could remove different percentages of other several common PMEs from the aqueous solution, especially exhibiting high binding capability on monoethylhexyl phthalate. These findings indicate that some specific LAB strains are able to detoxify phthalate monoesters and may be useful to protect humans and/or animals from the adverse health effects of PAEs.