Combining strains of lactic acid bacteria may reduce their toxin and heavy metal removal efficiency from aqueous solution

Aims: The primary objective of this study was to compare the removal of cadmium, lead, aflatoxin B-1 and microcystin-LR from aqueous solution by Lactobacillus rhamnosus GG, L. rhamnosus LC705, Propionibacterium freudenreichii shermanii JS and Bifidobacterium breve Bbi99/E8, separately and in combination. Methods and Results: The removal of toxins and heavy metals was assessed in batch experiments. The removal of all compounds was observed to be strain specific. The removal of lead by a combination of all the strains used was observed to be lower than could be predicted from the removal by single strains (P < 0.05). A similar trend was also observed with the other compounds studied. Conclusions: The results show that the toxin-removal capacity of a combination of strains of lactic acid bacteria is not the sum of their individual capacities. Therefore, pure single strains should be used when the goal is to remove single compounds. The use of combinations of strains may be beneficial when several compounds are removed together. This needs to be studied in future experiments. Significance and Impact of the Study: Lactic acid bacteria have been identified as potent tools for the decontamination of heavy metals, cyanotoxins and mycotoxins. The results of this study should be considered when selecting combinations of bacteria for the simultaneous removal of several toxic compounds.