TITLE:
Phylogeny of Bacteria from Steelmaking Wastes and Their Acidic Enrichment Cultures
AUTHORS:
Mariana P. Reis, Flaviane A. Pinheiro, Patrícia S. Costa, Ana Paula C. Salgado, Paulo S. Assis, Edmar Chartone-Souza, Andréa M. A. Nascimento
KEYWORDS:
Bacteria, 16S rRNA, Diversity, Zinc, Steelmaking Wastes
JOURNAL NAME:
Advances in Microbiology,
Vol.4 No.12,
September
23,
2014
ABSTRACT: Currently,
millions of tons of steel are produced worldwide. This has become a serious
economic and environmental challenge because the ores used for steel production
are nonrenewable resources and the production generates huge amount of waste.
In this study, we identified and investigated the ability of bacteria from
steelmaking waste with low and high zinc concentration to promote leaching of
zinc, when enriched by acidic (pH 2) culture conditions. The bioleaching assays
indicated removal of Zn, as in chemical leaching. Bacterial communities from
crude and enrichment culture wastes were characterized by the 16S rRNA gene.
Phylogenetic analysis of the generated clone libraries revealed predominance of
Proteobacteria and Firmicutes. The Actino- bacteria, Bacteroidetes,
Cyanobacteria, and Deinococcus-Thermus phyla were also encountered. The clones
were most closely related to cultivable heterotrophic bacteria. Different
genera were identified including iron redox cycling and leaching bacteria such
as Chromobacterium, Aeromonas, Escherichia, Bacillus,
and Ochrobactrum. These data add
significant new information on bacteria which survive in extremely acidic
conditions. They are distantly related to typical acidophiles responsible for
the leaching process, which makes them good candidates for future studies on
metal bioleaching.