Treatment of Chromium Pollution by the Reductase Enzyme Generated by a Chromium-Resistant Bacterium Isolated in Dewatering Sludge

Paul Fabrice Nguema, Zejiao Luo, Zachari Mohamadou Mounir, Ma Jun


An efficient Cr (VI)-resistant and reducing bacterial strain was successfully isolated in dewatering sludge collected from a sewage treatment plant, and characterized in vitro Cr (VI) reduction through a reductase enzyme. Phylogenetic analysis using 16S rDNA gene sequencing revealed that the newly isolated strain namely Pf-1 was closely related to Bacillus cereus. The strain almost reduced 0.17 mM Cr (VI) within 24h incubation and the presence of different substrates such as glucose, sucrose, or acetate significantly enhanced the reduction rate of Cr (VI) to Cr (III). However, addition of the same substrate at the stationary phase of the microbial growth increased the reduction rate as well as bacterial growth. Additionally, raising the concentration of thiosulfate in the medium doubled the reduction rate under similar conditions. Assay with different fractions of the cells demonstrated that the reductase enzyme activity was mainly associated with the cytoplasmic fraction. The maximum activity was 23.3 µM h-1 mg-1 protein and was obtained at the Cr (VI) concentration of 2 mM. The promising strain can be efficiently employed for bioremediation of Cr (VI) polluted sites.

Full Text:



Copyright (c) 2017 Paul Fabrice Nguema, Zejiao Luo, Zachari Mounir, Ma Jun

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

International Journal of Biology   ISSN 1916-9671(Print)   ISSN 1916-968X  (Online)   Email:

Copyright © Canadian Center of Science and Education

To make sure that you can receive messages from us, please add the '' domain to your e-mail 'safe list'. If you do not receive e-mail in your 'inbox', check your 'bulk mail' or 'junk mail' folders.


scholar_logo_lg_2011_120 proquest_logo_120 lockss_logo_2_120