Binding of aflatoxin B₁ to cell wall components of Lactobacillus rhamnosus strain GG

Abstract

The surface of Lactobacillus rhamnosus strain GG (LGG) has previously been shown to bind aflatoxin B₁ (AFB₁) effectively, it being a food-borne carcinogen produced by certain species of Aspergillus fungi. To establish which components of the cell envelope are involved in the AFB₁ binding process, exopolysaccharides and a cell wall isolate containing peptidoglycan were extracted from LGG and its AFB₁ binding properties were tested. LGG was also subjected to various enzymatic and chemical treatments and their effects on the binding of AFB₁ by LGG were examined. No evidence was found for exopolysaccharides, cell wall proteins, Ca²⁺ or Mg²⁺ being involved in AFB₁ binding. The AFB₁ binding activity of the cell wall isolate indicates that AFB₁ binds to the cell wall peptidoglycan of LGG or compounds tightly associated with the peptidoglycan.

Keywords:

• Lactobacillus rhamnosus strain GG
• toxin binding
• cell wall peptidoglycan
• aflatoxin

Acknowledgements

Research was funded by the Key Centre for Applied and Nutritional Toxicology, RMIT-University, and by grants from the Faculty of Life Sciences, RMIT-University. S. J. L. was a recipient of a University of Turku Exchange Scholarship under the University of Turku-RMIT Student Exchange Program; C. A. H. was a recipient of an RMIT-University postdoctoral fellowship. The authors thank Eine Huttunen (University of Helsinki) for helpful discussions.

Notes

¶Present address: Australian Water Quality Centre, Private Mail Bag 3, Salisbury, South Australia 5108, Australia.

§Present address: Functional Foods Forum, University of Turku, Itäinen pitkäkatu 4, FIN-20520 Turku, Finland.

§Present address: Functional Foods Forum, University of Turku, Itäinen pitkäkatu 4, FIN-20520 Turku, Finland.

Additional information

Notes on contributors

J. T. Ahokas

¶Present address: Australian Water Quality Centre, Private Mail Bag 3, Salisbury, South Australia 5108, Australia. §Present address: Functional Foods Forum, University of Turku, Itäinen pitkäkatu 4, FIN-20520 Turku, Finland.