Andronikashvili Institute of Physics, 6, Tamarashvili Str, 0177 Tbilisi, Georgia.
J Ind Microbiol Biotechnol. 2011 Nov;38(11):1803-8. doi: 10.1007/s10295-011-0967-y. Epub 2011 May 6.
Natural habitats are often characterized by the coexistence of Zn and Cr. This study assessed the potential of two Gram-positive, Cr(VI)-reducing, aerobic bacterial strains belonging to Arthrobacter genera, which were isolated from basalt samples taken from the most polluted region of the Republic of Georgia, to remediate Cr(VI) in environments in the presence of Zn(II). Our batch experiments revealed that the addition of Zn(II) to the tested bacterial cells significantly enhanced the accumulation of Cr. According to electron spin resonance (ESR) measurements, the presence of Zn(II) ions did not change the nature of Cr(V) and Cr(III) complexes generated during the microbial reduction of Cr(VI). The efficiency of Cr(VI) reduction also remained unchanged after the addition of 50 mg/l of Zn(II) to the bacterial cells. However, at high concentrations of Zn(II) (higher than 200 mg/l), the transformation of Cr(VI) to Cr(V) and Cr(III) complexes decreases significantly. In addition, it was shown that the accumulation pattern of Zn in the tested bacterial species in the presence of 100 mg/l of Cr(VI) fits the Langmuir-Freundlich model well. The two tested bacterial strains exhibited different characteristics of Zn accumulation.
自然栖息地通常具有共存的 Zn 和 Cr。本研究评估了从格鲁吉亚污染最严重地区的玄武岩样本中分离出的两种属于节杆菌属的革兰氏阳性、六价铬还原、需氧细菌菌株在存在 Zn(II) 的情况下修复环境中六价铬的潜力。我们的批处理实验表明，向测试细菌细胞中添加 Zn(II) 可显著促进 Cr 的积累。根据电子自旋共振 (ESR) 测量，在微生物还原六价铬过程中产生的 Cr(V) 和 Cr(III) 复合物的性质没有因 Zn(II) 离子的存在而改变。向细菌细胞中添加 50mg/L 的 Zn(II) 后，六价铬的还原效率仍保持不变。然而，当 Zn(II) 的浓度较高（高于 200mg/L）时，Cr(VI)向 Cr(V)和 Cr(III)复合物的转化显著减少。此外，还表明在存在 100mg/L 的六价铬的情况下，测试细菌物种中 Zn 的积累模式很好地符合 Langmuir-Freundlich 模型。两种测试的细菌菌株表现出不同的 Zn 积累特征。
