RESUMO
In order to investigate the binding ability of Lactobacillus strains to Benzo(a)pyrene (BaP), 15 strains were analysed. L. plantarum CICC 22135 and L. pentosus CICC 23163 exhibited high efficiency in removing BaP from aqueous medium; the binding rates were 66.76% and 64.31%, respectively. This process was affected by temperature, incubation time and pH, and cell viability was not necessary for the binding ability. Additionally, both strains, especially strain CICC 23163 showed high specificity in binding BaP. The cell-BaP complexes were stable in aqueous medium. The mechanism of binding was investigated by examining the binding ability of different components of the microorganism cells. The results revealed that peptidoglycans played an important role in binding BaP and its structural integrity was required. Consequently, we proposed that the mechanism of this process was a physisorption and peptidoglycan was the main binding site. These two strains may be used for dietary detoxification in human diet and animal feed.
Assuntos
Proteínas de Bactérias/metabolismo , Benzo(a)pireno/metabolismo , Carcinógenos/metabolismo , Contaminação de Alimentos/prevenção & controle , Lactobacillus/metabolismo , Peptidoglicano/metabolismo , Adsorção/efeitos da radiação , Proteínas de Bactérias/análise , Proteínas de Bactérias/química , Proteínas de Bactérias/efeitos da radiação , Benzo(a)pireno/toxicidade , Sítios de Ligação/efeitos da radiação , Carcinógenos/toxicidade , Parede Celular/química , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Lactobacillus/efeitos dos fármacos , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/efeitos da radiação , Lactobacillus plantarum/efeitos dos fármacos , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/metabolismo , Lactobacillus plantarum/efeitos da radiação , Glicoproteínas de Membrana/análise , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/metabolismo , Viabilidade Microbiana , Peptidoglicano/análise , Peptidoglicano/química , Peptidoglicano/efeitos da radiação , Estabilidade Proteica/efeitos da radiação , Sonicação , Esferoplastos/química , Esferoplastos/efeitos dos fármacos , Esferoplastos/metabolismo , Propriedades de Superfície/efeitos da radiação , Ácidos Teicoicos/análise , Ácidos Teicoicos/metabolismo , TemperaturaRESUMO
OBJECTIVE: We studied the ability of Lactobacillus plantarum 121 and Lactobacillus pentosus ML32 to bind benzo(a)pyrene. METHODS: The percentage of benzo(a)pyrene bound by the lactobacilli strains was quantitated by HPLC after bacterial cells and benzo(a)pyrene were co-incubated in MRS media at 37 degrees C for 4 h. RESULTS: The percentage of benzo(a)pyrene-binding was 65.9% for 121 and 64.9% for ML32. Physical factors affecting binding ability included incubation time, temperature, bacterial cell viability, pH and concentrations of Ca2+ and Mg2+. Different chemical and enzymatic treatments to cells affected the binding of the two strains to benzo(a)pyrene. The simulation of gastrointestinal environments showed that the binding ability of the two strains depended largely upon pH and bile salt concentrations, but less upon treating time. Trypsin had only influence on the ability of 121 to bind benzo(a)pyrene. The presence of benzene in washing cell impaired the ability of the two strains to bind benzo(a)pyrene. CONCLUSIONS: Strains 121 and ML32 had potential to bind benzo(a)pyrene.