高效降解展青霉素乳酸菌的分离鉴定及去除机理研究
Isolation and identification of lactic acid bacteria with efficient patulin degradation ability and its degrading characteristics
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摘要: 目的:从发酵食品材料中筛选出对展青霉素（PAT）有去除作用的乳酸菌。方法:将从传统发酵蔬菜中分离得到的乳酸菌与展青霉素共培养,利用高效液相色谱法（HPLC）测定共培养体系中PAT毒素的减少量,筛选出一株高效去除PAT毒素的乳酸菌菌株。通过微生物形态学、16S r DNA测序鉴定,确定该菌的系统分类学地位。通过比较不同致死方式对实验菌株去除展青霉素效能的影响,并研究细胞壁和胞内物质对PAT的去除效果,初步探索乳酸菌去除展青霉素的机理。最后研究不同因素处理对实验菌株去除PAT毒素的影响。结果:从发酵食品材料中筛选出一株高效去除PAT的菌株LB-11,经初步鉴定该菌株为植物乳杆菌（Lactobacillus plantarum）。致死菌和细胞壁的去除效率显著低于有活性的完整菌体,推测乳酸菌去除展青霉素主要机理为生物降解作用。在温度为2030℃和p H为37的条件下实验菌株对PAT均有较高的去除效率。结论:LB-11对PAT具有较高的去除效率,在合适的条件下,在24 h内对PAT的去除率达到了98.34%,是一株极具应用价值的益生菌。Abstract: Objective:To screen and identify a lactic acid bacteria(LAB) strain with patulin(PAT) detoxification ability from fermented food. Methods:LAB strains isolated from fermented vegetables were co-cultured with PAT. Then the HPLC method was executed to determine the PAT residue after co-culture and one LAB strain with high PAT-degrading ability was selected for further study. The PAT removal efficiency of viable cells and dead cells,as well as different cell components including cell pellets,cell walls and cell extracts were compared,and the factors that impact the capability of PAT degradation of this strain were studied. Moreover,the strain's taxonomy was confirmed based on morphology characteristics and 16 S r DNA gene sequence analysis. Results:A LAB strain with high PAT-removing ability was screened out and identified as a Lactobacillus plantarum. The PAT removal efficiency of dead cells and cell wall were much lower than cell pellets,indicating that the removal mechanism may be attributed to biodegradation. This L. plantarum strain had high PAT-removing ability at temperature of 20~30 ℃ and p H of 3~7. Conclusion:The L. plantarum strain LB-11 had a high removal ability of PAT. The removal efficiency of PAT could reach 98.34% under appropriate conditions within 24 h. This strain could be regarded as a probiotic with potential application on PAT removal.
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