Heavy Metal Resistances and Chromium Removal of a Novel Cr(VI)-Reducing Pseudomonad Strain Isolated from Circulating Cooling Water of Iron and Steel Plant
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- 作者：Jian-Kun Zhang ; Zhen-Hua Wang ; Yun Ye
- 关键词：Pseudomonas sp. ; Heavy metal resistance ; Chromate reduction ; Chromium removal ; Chromate reductase ; Bioremediation
- 刊名：Applied Biochemistry and Biotechnology
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：180
- 期：7
- 页码：1328-1344
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Biotechnology; Biochemistry, general;
- 出版者：Springer US
- ISSN：1559-0291
- 卷排序：180
文摘
Three bacterial isolates, GT2, GT3, and GT7, were isolated from the sludge and water of a circulating cooling system of iron and steel plant by screening on Cr(VI)-containing plates. Three isolates were characterized as the members of the genus Pseudomonas on the basis of phenotypic characteristics and 16S rRNA sequence analysis. All isolates were capable of resisting multiple antibiotics and heavy metals. GT7 was most resistant to Cr(VI), with a minimum inhibitory concentration (MIC) of 6.5 mmol L−1. GT7 displayed varied rates of Cr(VI) reduction in M2 broth, which was dependent on pH, initial Cr(VI) concentration, and inoculating dose. Total chromium analysis revealed that GT7 could remove a part of chromium from the media, and the maximum rate of chromium removal was up to 40.8 %. The Cr(VI) reductase activity of GT7 was mainly associated with the soluble fraction of cell-free extracts and reached optimum at pH 6.0∼8.0. The reductase activity was apparently enhanced by external electron donors and Cu(II), whereas it was seriously inhibited by Hg(II), Cd(II), and Zn(II). The reductase showed a Km of 74 μmol L−1 of Cr(VI) and a Vmax of 0.86 μmol of Cr(VI) min−1 mg−1 of protein. The results suggested that GT7 could be a promising candidate for in situ bioremediation of Cr(VI).