Detoxifying ability of marine bacterium Flavobacterium sp against a toxic contaminant in the reagent sodium chloride to Nannochloropsis oculata

A specific lot of sodium chloride (NaCl) has a contaminant toxic to the gro wth of Nannochloropsis oculata. This toxic effect was markedly reduced by c o-culture with Flavobacterium so., and such detoxifying ability was specifi c to this bacterial strain. Bioassays of the NaCl after heat treatment and ultrafiltration indicated that the NaCl was contaminated with heat-labile o rganic compounds of low molecular weight. Chemical analysis indicated that one contaminant in NaCl had analogous structure to a fungicide tridemorph. Commercially available tridemorph showed a toxic effect on N. oculata, and it was reduced by co-culture with Flavobacterium sc. These results indicate that the tridemorph-like substance is a causative factor for the growth in hibition of N. oculata, and that Flavobacterium sp. has an ability to detox ify the contaminant as well as tridemorph. The detoxifying ability of Flavo bacterium sp. has the potential to be widely applicable for removing the tr ace pollutants affecting the growth of microalgae.