Heterotrophic Bacterial Population in Acid Coal Mine Water: Flavobacterium acidurans sp. n. 1

Acid water from a closed deep coal mine was examined for the presence of heterotrophic bacteria. This water, which is routinely pumped to a surface stream for runoff, did not contain “acid streamers” or slime-producing, sporeforming bacteria. However, aerobic, nonmotile, yellow, nonfermentative, gram-negative rods were found by using the most-probable-number technique with a dilute tryptone-yeast extract medium. The isolates displayed binary fission as the mode of reproduction although abortive division, as evidenced by mini-cell formation, occurred at a low frequency. Based on morphological and other characteristics, including deoxyribonucleic acid base composition, a new species, Flavobacterium acidurans, is proposed for these bacteria. The type strain of this organism is ATCC 27383. Periodic sampling of mine effluent over a 1-year period disclosed that this organism comprises a major microbial component of the acid environment.