Uranium tolerant phosphate solubilizing bacteria isolated from Gogi, a proposed uranium mining site in South India

摘要

Remediation of uranium contamination presents a significant environmental problem worldwide. Bioremediation has gained increasing importance as a feasible and eco-friendly strategy. Uranium tolerant phosphate solubilizing bacteria are considered as important candidates in the development of bioremediation technology. In this context, we have isolated bacteria from a proposed uranium mining site, Gogi in the Bhima river belt of Karnataka (South India) with special reference to phosphate solubilizers. Out of 270 bacteria isolated, 14 isolates solubilized 148.5-1226.6 mgL(-1) phosphate from 5 g L-1 tri-calcium phosphate accompanied by drop in media pH from an initial 6.9 to pH values between 3.9 and 6.3. Phylogenetic analysis of 14 phosphate solubilizing bacteria by 16S rRNA gene sequencing grouped them into three phyla, namely Firmicutes, Proteobacteria and Actinobacteria. When tested for uranium sensitivity, 12 of the 14 phosphate solubilizing isolates showed significant (p < 0.01) tolerance to uranium (4.1%-26.1%) compared to the reference strain Escherichia coli ATCC 25922(T). This demands further in-depth studies on microbial inhabitants from such complex environmental conditions that could provide better agents and insights for remediation technology.