Isolation of highly copper-tolerant fungi from the smelter of the Naganobori copper mine, an historic mine in Japan.
OBJECTIVE
Copper is a critical metal of modern industry, and is the most widespread heavy metal contaminant in wastewater. Therefore, isolation of copper-tolerant microbes having the potential as biosorbent is fascinating not only from an environmental microbiology, but also from a biotechnology view point. In this study, we attempted to isolate highly copper-tolerant microbes from soil samples of the Nabanobori copper mine, the oldest mine in Japan.


RESULTS
As a result of an enrichment culture, two fungal strains were isolated from soil of the smelter remains. The isolates could grow in a maximum of 200 mmol l(-l) Cu(2+), and grew under a wide pH range. The Cu(2+)-binding capacity of nontreated biomass of the isolates was around 35 mg Cu(2+) g(-1)-biomass. Analysis of 18S rDNA suggested that the isolates belong to the Aspergillus/Penicillium clade, but they represented a distinct lineage against known neighbours.


CONCLUSIONS
The isolates were highly copper-tolerant, and their Cu(2+)-binding capacity was comparable to well-studied fungal sorbents. The isolates were implied as novel species. Soil of the historic old mine under weather-beaten conditions might be a suitable source for metal-tolerant microbes.


CONCLUSIONS
The present results advance our understanding of metal-tolerant microbes, and offer a new tool for both environmental control and metal recovery operations.
Fujii
K
K
Department of Agriculture, Yamaguchi University, Yoshida, Yamaguchi, Japan. kfujii@yamaguchi-u.ac.jp
Fukunaga
S
S
D018533:Biomass; D003300:Copper / Q000494:pharmacology*; D003470:Culture Media; D005658:Fungi / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D007564:Japan; D008906:Mining; D012337:RNA, Ribosomal, 18S / Q000032:analysis
D003470:Culture Media; D012337:RNA, Ribosomal, 18S; D003300:Copper