Analytical and Testing Center of Hebei Province, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China.
College of Food Science and Biology, Hebei University of Science and Technology, No.26 of Yuxiang street, Shijiazhuang 050018, Hebei Province, China.
J Hazard Mater. 2023 Aug 5;455:131519. doi: 10.1016/j.jhazmat.2023.131519. Epub 2023 Apr 28.
This research provided an excellent novel hexavalent chromium (Cr(VI))-removal bacterium, Bacillus paramycoides Cr6, and investigated its removal mechanism from the perspective of molecular biology. Cr6 could resist up to 2500 mg/L Cr(VI), and the removal rate of 2000 mg/L Cr(VI) reached 67.3% under the optimal culture conditions of 220 r/min, pH 8 and 31 ℃. When the initial concentration of Cr(VI) was 200 mg/L, Cr6 had a removal rate of 100% within 18 h. The differential transcriptome analysis identified two key structural genes named bcr005 and bcb765 of Cr6, which were upregulated by Cr(VI). Their functions were predicted and further confirmed by bioinformatic analyses and in vitro experiments. bcr005 encodes Cr(VI)-reductase BCR005, and bcb765 encodes Cr(VI)-binding protein BCB765. Real-time fluorescent quantitative PCRs were performed, and the data illustrated a parallel pathway (one is Cr(VI) reduction, and the other is Cr(VI) immobilisation) of Cr6 to remove Cr(VI), which relies on the synergistic expression of the genes bcr005 and bcb765 induced by different concentrations of Cr(VI). In summary, a deeper molecular mechanism of Cr(VI) microorganism removal was elaborated; Bacillus paramycoides Cr6 was an exceptional novel Cr(VI)-removed bacterial resource, while BCR005 and BCB765 were two new-found efficient enzymes that have potential practical applications for sustainable microbial remediation of Cr-contaminated water.
本研究提供了一种出色的新型六价铬（Cr(VI)）去除细菌，即解淀粉芽孢杆菌 Cr6，并从分子生物学角度研究了其去除机制。Cr6 可耐受高达 2500mg/L 的 Cr(VI)，在 220r/min、pH8 和 31℃的最佳培养条件下，对 2000mg/L Cr(VI)的去除率达到 67.3%。当 Cr(VI)的初始浓度为 200mg/L 时，Cr6 在 18h 内的去除率达到 100%。差异转录组分析鉴定出 Cr6 中两个关键的结构基因 bcr005 和 bcb765，它们受 Cr(VI)的诱导而上调。通过生物信息学分析和体外实验预测并进一步证实了它们的功能。bcr005 编码 Cr(VI)-还原酶 BCR005，而 bcb765 编码 Cr(VI)-结合蛋白 BCB765。进行了实时荧光定量 PCR 分析，数据表明 Cr6 去除 Cr(VI)有一个平行途径（一条是 Cr(VI)还原，另一条是 Cr(VI)固定），这依赖于不同浓度 Cr(VI)诱导的基因 bcr005 和 bcb765 的协同表达。总之，阐述了 Cr(VI)微生物去除的更深层次的分子机制；解淀粉芽孢杆菌 Cr6 是一种新型的、具有特殊性质的 Cr(VI)去除细菌资源，而 BCR005 和 BCB765 是两种新发现的高效酶，它们具有可持续微生物修复 Cr 污染水的潜在实际应用价值。
