Ultrasound-Assisted Detoxification of Ochratoxin A: Comparative Study of Cell Wall Structure, Hydrophobicity, and Toxin Binding Capacity of Single and Co-culture Lactic Acid Bacteria

The present study aimed to evaluate the binding capacity and stability of ochratoxin A (10 mu g/kg; OTA) by single and co-culture Lactobacillus acidophilus + Lactobacillus rhamnosus in various modes including viable, heat-, and ultrasound-inactivated cells as well as a combination of viable + heat- or ultrasound-inactivated cells. The stability of OTA binding on native and modified lactic acid bacteria (LAB) surface was conducted after washing with solvent. The highest OTA adsorption capacity and stability (mu g/kg) were obtained after co-culture L. acidophilus + L. rhamnosus in the following order: ultrasound-treated (8.418 and 7.829) > viable + ultrasound-treated (8.376 and 7.204) > heat-treated (7.588 and 6.987) > viable + heat-treated (7.536 and 6.483) > viable (7.425 and 5.157). The surface hydrophobicity obtained by spectrophotometry (%) enhanced from 40.5% in viable to 71.9% and 60.6% in ultrasound and heat-treated L. acidophilus + L. rhamnosus. alpha-helix and beta-turn structures in L. acidophilus + L. rhamnosus reduced to (20.7 and 22.6%) and (26.9 and 27.2%) further LAB inactivated by thermosensation and heating compared to alpha-helix and beta-turn structures in viable LAB, respectively (16.1 and 26.1%). To prove that the reduction of the OTA by LAB caused a substantial reduction of their toxic performances, micronucleus (MN) experiments were carried out with human-derived hepatoma cell line cells. Indeed, a considerable decrease of OTA caused a substantial reduction of MN induction and the inhibition of the cell division rates (i.e., the decline of BNC formation) by the OTA was significantly reduced in the ultrasonicated L. acidophilus + L. rhamnosus.

Automated summary

This study aimed to evaluate the binding capacity and stability of ochratoxin A (OTA) by single and co-culture Lactobacillus acidophilus + Lactobacillus rhamnosus in various modes. It was found that ultrasound-treated L. acidophilus + L. rhamnosus exhibited the highest OTA adsorption capacity and stability. Additionally, the reduction of OTA significantly decreased its toxic performances on cells.