Removal of microcystin-LR by lactic acid bacteria

Abstract:

Abstract:【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 (109 CFU/mL, pH 7, 37 ?C), 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, 1010 CFU/mL, pH 7.0, 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.

Key words:Keywords: Microcystin; Lactobacillus; Food security; Metabolic activity