Abou-Shanab R A I, Angle J S, van Berkum P
Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, Mubarak City for Scientific Research, Borg El-Arab, Alexandria, Egypt.
Int J Phytoremediation. 2007 Mar-Apr;9(2):91-105. doi: 10.1080/15226510701232708.
A total of 85 chromate-resistant bacteria were isolated from the rhizosphere of water hyacinth grown in Mariout Lake, Egypt, as well as the sediment and water of this habitat. Only 4 (11%), 2 (8%), and 2 (8%) of isolates from each of the environments, respectively, were able to tolerate 200 mg Cr (VI) L(-1). When these eight isolates were tested for their ability to tolerate other metals or to reduce chromate, they were shown to also be resistant to Zn, Mn, and Pb, and to display different degrees of chromate reduction (28% to 95%) under aerobic conditions. The isolates with the higher chromate reduction rates from 42% to 95%, (RA1, RA2, RA3, RA5, RA7, and RA8) were genetically diverse according to RAPD analysis using four differentprimers. Bacterial isolates RA1, RA2, RA3, RAS, and RA8 had 16 S rRNA gene sequences that were most similar to Pseudomonas diminuta, Brevundimonas diminuta, Nitrobacteria irancium, Ochrobactrum anthropi, and Bacillus cereus, respectively. Water hyacinth inoculated with RA5 and RA8 increased Mn accumulation in roots by 2.4- and 1.2-fold, respectively, compared to uninoculated controls. The highest concentrations of Cr (0.4 g kg(-1)) and Zn (0.18 g kg(-1)) were accumulated in aerial portions of water hyacinth inoculated with RA3. Plants inoculated with RA1, RA2, RA3, RA5, RA7, and RA8 had 7-, 11-, 24-, 29-, 35-, and 21-fold, respectively, higher Cr concentrations in roots compared to the control. These bacterial isolates are potential candidates in phytoremediation for chromium removal.
从埃及玛丽奥特湖生长的凤眼莲根际以及该栖息地的沉积物和水中总共分离出85株耐铬细菌。分别来自每个环境的分离株中只有4株（11%）、2株（8%）和2株（8%）能够耐受200 mg Cr（VI）L⁻¹。当测试这八株分离株耐受其他金属或还原铬酸盐的能力时，发现它们对锌、锰和铅也具有抗性，并且在有氧条件下表现出不同程度的铬酸盐还原（28%至95%）。根据使用四种不同引物的RAPD分析，铬酸盐还原率较高（42%至95%）的分离株（RA1、RA2、RA3、RA5、RA7和RA8）在基因上具有多样性。细菌分离株RA1、RA2、RA3、RAS和RA8的16S rRNA基因序列分别与微小假单胞菌、短小短波单胞菌、伊朗硝化细菌、嗜水气单胞菌和蜡样芽孢杆菌最为相似。与未接种的对照相比，接种RA5和RA8 的凤眼莲根部的锰积累分别增加了2.4倍和1.2倍。接种RA3的凤眼莲地上部分积累的铬（0.4 g kg⁻¹）和锌（0.18 g kg⁻¹）浓度最高。与对照相比，接种RA1、RA2、RA3、RA5、RA7和RA8的植物根部的铬浓度分别高出7倍、11倍、24倍、29倍、35倍和21倍。这些细菌分离株是植物修复中去除铬的潜在候选菌株。
