Characterization of a Rhizobium larrymoorei FJ Exhibiting High Level Cr(VI) Reduction Potential
The investigation was conducted to evaluate mechanism of Cr(VI) resistance and reduction by a bacterial strain named FJ under different conditions. This strain, identified as a member of Rhizobium larrymoorei by analysis of its 16S rRNA gene sequence was previously isolated from a paddy soil contaminated by e-waste recycling. Good Cr(VI) reduction ability catalyzed by growing cells of R. larrymoorei FJ was observed in batch cultures conducted at different initial Cr(VI) concentrations. Up to 83.23% reduction was shown in LB medium supplemented with 2.50 mM Cr(VI). Cr(VI) was transformed to some soluble form of Cr(III) due to anaerobic respiration. Biosorption was also observed in the process of bioreduction. But only loosely cell-surface binding Cr(VI) was detected in cells grown in medium supplied with different concentrations of Cr(VI). Present of yeast or citrate could enhance Cr(VI) reduction of resting cells. However, Cr(VI) reduction by resting cells was only observed at Cr(VI) concentration lower than 0.25 mM. R. larrymoorei FJ exhibited a high efficiency of Cr(VI) reduction at temperatures from 28°C to 37°C and pH values from 6.0 to 7.0.
Hexing Li, Qunjie Xu and Daquan Zhang
J. H. Zhang "Characterization of a Rhizobium larrymoorei FJ Exhibiting High Level Cr(VI) Reduction Potential", Advanced Materials Research, Vols. 356-360, pp. 1009-1014, 2012