乳杆菌吸附苯并芘的特性

目的]探讨植物乳杆菌(Lactobacillus plantarum)121和戊糖乳杆菌(Lactobacillus pentosus)ML32的苯并芘吸附作用与机制.方法]采用高效液相色谱检测菌体对苯并芘的吸附率.结果]菌株121和ML32对苯并芘的吸附率分别为65.9%和64.9%,这种吸附特性与菌体活力无关,随培养时间延长、温度提高以及细胞浓度的上升而增加.菌株121和ML32的吸附率在pH 4和5时达到最大,分别为87.6%和89.0%.当培养液中Ca2+或Mg2+浓度大于0.05mol/L时,菌体吸附率与盐离子浓度呈正相关.苯洗脱会导致乳杆菌所吸附的苯并芘减少90%.经碱性蛋白酶、中性蛋白酶、溶菌酶及TCA和SDS等方法处理后,菌体吸附率上升,且不易被苯去除.在胆盐及胃酸环境下,两株菌的吸附率均提高至70%以上,而胰蛋白酶的存在仅对菌株121的吸附率有较大影响.结论]两株乳杆菌可以通过吸附作用从环境中清除苯并芘,其吸附效果与细菌细胞壁的结构和组成有关.

Binding of benzo(a)pyrene by Lactobacilli strains

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℃ 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.