Bacterial degradation of microcystin toxins in drinking water eliminates their toxicity

Microcystin-LR and -LA were readily biodegraded by a bacterium, Sphingpoyxis sp. LH21, in a treated reservoir water. Detection of the microcystins was conducted using high-performance liquid chromatography (HPLC), protein phosphatase 2A (PP2A) inhibition assay and a cell-based cytotoxicity assay. The HPLC results correlated well with the two assays. The decrease in cytotoxicity, coupled with the associated decrease in microcystin concentrations, indicated that no cytotoxic by-products were being generated, highlighting the applicability of biodegradation as a feasible treatment option for effective microcystin removal.