Factors affecting the sequestration of aflatoxin by Lactobacillus rhamnosus strain GG

The interaction of a potent carcinogen, aflatoxin B-1 (AFB(1)), with a prob iotic strain of lactic acid bacteria, Luctobacillus rhamnosus strain GG (GG ), has been investigated. The binding of AFB(1) to GG in the late exponenti al-early stationary phase was studied for viable, hr at-killed and acid-kil led bacteria. In general, viable, heat-killed and acid-killed GG responded in a similar manner. The effects of pronase E, lipase and m-periodate on AF B(1) binding and release were consistent with AFB(1) binding predominantly to carbohydrate components of the bacteria. The effect of urea suggested hy drophobic interactions play a major role in binding. Increasing concentrati on (0.01-1 M) of NaCl or CaCl2 had minor effects on AFB(1) binding suggesti ng some involvement of electrostatic interactions. An increase in pH from 2 .5 to 8.5 had no effect on AFB(1) binding but decreased binding of AFB(2a), possibly due to hydrogen bonding interactions. (C) 2000 Elsevier Science I reland Ltd. All rights reserved.