乳酸菌对微囊藻毒素的清除

Removal of microcystin-LR by lactic acid bacteria

【目的】研究唾液乳杆菌(Lactobacillus salivarius BBE09-18)、发酵乳杆菌(L.fermentum BBE09-29)以及干酪乳杆菌(L.casei Zhang)对藻毒素的清除能力以及影响乳酸菌清除藻毒素的主要因素,以期为进一步解析乳酸菌清除藻毒素的作用机制提供理论基础,并为去除食品体系中的藻毒素提供新的思路。【方法】研究乳酸菌细胞的不同生理状态(活细胞与死细胞)对藻毒素清除能力的影响,考察菌浓差异、起始藻毒素浓度差异、葡萄糖的供给等对乳酸菌清除藻毒素效能的影响。【结果】3株实验乳酸菌均具有清除藻毒素的能力,其中,L.casei Zhang的藻毒素清除能力最强,当藻毒素初始浓度为150μg/L时,24h后残留藻毒素浓度为85.5μg/L,清除率可达43%。此外,研究还发现乳酸菌活细胞的清除能力显著高于热失活后的死细胞。添加外源物质葡萄糖能显著提高实验菌株清除藻毒素的效率,在初始浓度为1800μg/L的藻毒素溶液中,当添加5%(w/v)葡萄糖后,L.casei Zhang经24h可清除92%的藻毒素。【结论】3株乳酸菌均具有藻毒素清除能力;同时,菌体浓度以及菌体自身的生理状态对藻毒素的清除效率具有重要影响,乳酸菌对藻毒素的清除可能与菌体的代谢活性相关。

【Objective】The performance of Lactobacillus salivarius BBE09-18,L. fermentum BBE09-29 and L. casei Zhang to remove the cyanobacterial toxin microcystin-LR （ MC-LR） were determined in this study,and the key factors related to the removal efficiency were investigated to analyze the specific mechanism and provide a novel way to deal with the MC-LR contaminated foods. 【Methods 】 Investigate the microcystin-removing capability of cells in different physiological status,e. g. viable and nonviable cells,and compare their removing effects with different biomass,toxin concentration and glucose supplement. 【Results】Among these strains,L. casei Zhang removed the microcystin-LR most effectively. After a removal treatment with L. casei Zhang for 24 h （10^9 CFU /mL,pH7,37℃ ）,the MC-LR concentration deduced from 150 μg /L to 85. 5 μg /L. Results also showed that the viable cells were more effective for MC-LR removal than the nonviable ones. Moreover,the removal performance can be improved significantly when glucose was added,and the maximum removal of 92% was observed for L. casei Zhang （ toxin initial concentration 1800 μg /L,10^10 CFU /mL,pH7. 0,37℃ ,24 h） with 5% glucose supplement. 【Conclusion】All of the three LAB used in this study can remove MC-LR. It can be confirmed that some factors,such as biomass,toxin concentration and energy supplement of cells play important roles on the removal efficiency. These results suggest further that the mechanism of MC-LR removal in LAB may be related to their metabolic activity.