Removal Of Benzo(a)Pyrene By Lactobacillus Strains In Simulated Starch Conditions

Lactobacillus have been evaluated having ability to remove various toxins. The performances of Lactobacillus strains in removing benzo(a)pyrene (B(a)P) in simulated starch conditions were studied. To provide a novel way to reduce the potential risk of B(a)P to human, several factors affect the binding of the 3 Lactobacillus strains to the chemical toxin were investigated in starch system. The percentage of B(a)P bound by Lactobacillus strains was determined with HPLC after incubation at 37℃ for 4 h. The B(a)P-removing capabilities of Lactobacillus strains in various simulated starch systems were evaluated, including the concentrations, types and gelatinization of starch, incubation time, pH and starch-hydrolyzed products. And the feasibility of Lactobacillus strains to binding B(a)P were investigated in Caco-2 cell model. What’s more the possible mechanisms of three lactobacilli strains to bind B(a)P has been researched. The following were main results.1. The B(a)P-binding percentages of the Lactobacillus strains increased as starch concentrations were elevated from 2% to 10%. Starch types, either from corn, potato or sweet potato, had little effects on the ability of these bacterial cells to bind B(a)P. The gelatinization of starch favored Lactobacillus strains to bind more B(a)P. Moreover, both glucose and maltose, the end products after starch ishydrolyzed, improved significantly the performance of the 3 bacterial strains to remove B(a)P.2. The percentage of these bacterial cells to bind B(a)P grew fast at 37℃ for the first 4 h-incubation time, and then slowly increased. The 3 Lactobacillus strains bound more B(a)P when starches were acidified to pH of 3 to 4 or alkalified to pH of 8 to 9. The viablecells of 3 Lactobacillus strains removed more B(a)P via their binding than their dead cells did.3. Through PCR technology to amplificating conservative regin, the DNA of 3 Lactobacillus strains did’t contain 2,3-dioxygen conservative regin. The mechanisms of three lactobacilli strains to bind B(a)P are more likely through physical binding rather than chemistry metabolizing.4. Lactobacillus strains have good effect to removal B(a)P in Caco-2 cell model systerm. Lactobacillus strains through binding B(a)P have little planting ability on cell, so large part of Lactobacillus strains will be excreted in vitro. In transcriptomc experiments, showed that Caco-2 cell expressed little cancer genes than Caco-2-B(a)P cell.