Promotion of Ni2+ Removal by Masking Toxicity to Sulfate-Reducing Bacteria: Addition of Citrate

International Journal of Molecular Sciences

Junwei Qian²  Xiaoyu Zhu²  Yong Tao²  Yan Zhou¹  Xiaohong He²  Daping Li² 

[1] College of Life Science, Sichuan University, Chengdu 610064, China; E-Mail:;Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences & Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu 610041, China; E-Mails:

关键词: Ni removal;    Ni-citrate complex;    toxicity masking;    lactate;    sulfate reduction;   

DOI  :  10.3390/ijms16047932

来源: mdpi

【 摘 要 】

The sulfate-reducing bioprocess is a promising technology for the treatment of heavy metal-containing wastewater. This work was conducted to investigate the possibility of promoting heavy metal removal by the addition of citrate to mask Ni²⁺ toxicity to sulfate-reducing bacteria (SRB) in batch reactors. SRB growth was completely inhibited in Ni²⁺-containing medium (1 mM) when lactate served as the sole carbon resource, leading to no sulfate reduction and Ni²⁺ removal. However, after the addition of citrate, SRB grew well, and sulfate was quickly reduced to sulfide. Simultaneously, the Ni-citrate complex was biodegraded to Ni²⁺ and acetate. The NiS precipitate was then formed, and Ni²⁺ was completely removed from the solution. It was suggested that the addition of citrate greatly alleviates Ni²⁺ toxicity to SRB and improves the removal of Ni²⁺, which was confirmed by quantitative real-time PCR targeting dissimilatory sulfite reductase (dsrAB) genes. Analysis of the carbon metabolism indicated that lactate instead of acetate served as the electron donor for sulfate reduction. This study offers a potential approach to increase the removal of heavy metals from wastewater in the single stage SRB-based bioprocess.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.