Isolation and identification of thiocyanate utilizing chemolithotrophs from gold mine soils

Abstract

A mixed bacterial culture capable of growing in potassium-thiocyanate containing medium (200 mg KSCN) has been isolated from bacterial suspensions of soil samples collected near gold mines in Kumjung (Korea). The isolates were initially characterized by metabolic profile analysis and were identified as Bacillus thermoglucosidasius, Bacillus cereus, Bacillus licheniformis, Bacillus mycoides, Brevibacterium epidermidis, Brevibacterium otitidis, and Corynebacterium nitrilophilus. One of the seven isolates was initially characterized as Brevibacterium epidermidis, which is not known to degrade thiocyanate. However, using 16S rDNA sequencing, this strain was identified as a member of Klebsiella. The strain shows high similarity values (95.8 to 96.4%) with Klebsiella species, and the closest known relative was found to be K. ornithinolytica ATCC 31898. The result indicates that species of the genus Klebsiella were the closest phylogenetic relatives of the investigated strain. This is the first known report of a member of Klebsiella that is capable of utilizing thiocyanate as sole source of carbon and nitrogen.