Cadmium-tolerant bacteria reduce the uptake of cadmium in rice: potential for microbial bioremediation.
Cadmium-tolerant bacteria reduce the uptake of cadmium in rice: potential for microbial bioremediation.
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DOI：
10.1016/j.ecoenv.2013.05.002
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发表时间：
2013-08
影响因子：
6.8
通讯作者：
S. Siripornadulsil;W. Siripornadulsil
中科院分区：
文献类型：
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作者：
S. Siripornadulsil;W. Siripornadulsil
我们选择了24个细菌菌株，可以耐受高达2500µM的CdCl 2从稻田的土壤下游的锌矿化区污染的高水平的镉（Cd）。在存在500µM CdCl 2的情况下，与不存在Cd的情况相比，所有分离株生长较慢且具有延长的滞后期。镉结合能力高，为6.38 ~ 9.38log[Cd（atom）]/cell。1 mMEDTA对Cd配合物在细菌中的稳定性有影响。在500µM CdCl 2中，所有分离株产生的无机硫化物和含SH基团的富硫化合物分别增加0.7至4.8倍和0.6至2.2倍。在24个耐镉细菌菌株中，KKU 2500 -3、-8、-9和-20能够在200µM CdCl 2存在下促进泰国茉莉稻（Kao Hom Mali 105）幼苗的生长，并且KKU 2500 -3产生最多的须根。有趣的是，当在200µM CdCl 2存在下生长时，这4个分离物增加了Cd耐受性，并使水稻中Cd的积累减少了61%，9%，6%和17%。在这4个菌株中，KKU 2500 -3在500-2000µM的CdCl 2中生长时产生更多的无机硫化物。XANES分析表明，当在500µM CdCl 2中生长时，该分离物沉淀出可检测量的硫化镉（CdS）。因此，分离物KKU 2500 -3可能将有毒的可溶性CdCl 2转化为无毒的不溶性CdS。通过16 S rDNA测序鉴定这些耐4Cd的细菌分离物，并将其分类为台湾贪铜菌KK 2500 -3和铜绿假单胞菌KK 2500 -8、-9和-20。
We selected 24 bacterial isolates that could tolerate up to 2500µM CdCl2from the soil of rice fields downstream from a zinc-mineralized area contaminated with a high level of cadmium (Cd). In the presence of 500µM CdCl2, all isolates grew slower and with a prolonged lag-phase compared to in the absence of Cd. Cd-binding capacity was high and ranged from 6.38 to 9.38log[Cd(atom)]/cell. The stability of Cd complexes in bacteria was affected by 1mM EDTA. In 500µM CdCl2, all isolates produced 0.7 to 4.8-fold more inorganic sulfide and 0.6 to 2.2-fold more thio-rich compounds containing SH groups. Out of 24 Cd-tolerant bacterial isolates, KKU2500-3, -8, -9 and -20 were able to promote the growth of Thai jasmine rice (Kao Hom Mali 105) seedlings in the presence of 200µM CdCl2, and KKU2500-3 produced the highest numbers of fibrous root. Interestingly, these 4 isolates increased Cd tolerance and decreased the accumulation of Cd in rice by 61, 9, 6, and 17% when grown in the presence of 200µM CdCl2. Of the 4 isolates, KKU2500-3 produced more inorganic sulfide when grown in CdCl2at 500–2000µM. XANES analyses indicated that this isolate precipitated a detectable amount of cadmium sulfide (CdS) when grown in 500µM CdCl2. Thus, the isolate KKU2500-3 could possibly transform toxic, soluble CdCl2into non-toxic, insoluble CdS. These 4Cd-tolerant bacterial isolates were identified via 16S rDNA sequencing and classified as Cupriavidus taiwanensis KKU2500-3 and Pseudomonas aeruginosa KKU2500-8, -9, and -20.