Abstract
An Gram negative strain of S. maltophilia, indigenous to environments contaminated by Cr(VI) and identified by biochemical methods and 16S rRNA gene analysis, reduced chromate by 100%, 98–99% and 92% at concentrations in the 10–70, 80–300, and 500 mg/L range, respectively at pH 7 and temperature 37 °C. Increasing concentrations of Cr(VI) in the medium lowered the growth rate but could not be directly correlated with the amount of Cr(VI) reduced. The strain also exhibited multiple resistance to antibiotics and tolerance and resistance to various heavy metals (Ni, Zn and Cu), with the exception of Hg. Hexavalent chromium reduction was mainly associated with the soluble fraction of the cell evaluated with crude cell-free extracts. A protein of molecular weight around 25 kDa was detected on SDS-PAGE gel depending on the concentration of hexavalent chromium in the medium (0, 100 and 500 mg/L). In silico analysis in this contribution, revealed the presence of the chromate reductase gene ChrR in S. maltophilia, evidenced through a fragment of around 468 bp obtained experimentally. High Cr(VI) concentration resistance and high Cr(VI) reducing ability of the strain make it a suitable candidate for bioremediation.
Highlights
Cr is a heavy metal belonging to the transition group (VI-B) of the modern periodic table
Contribution, we we demonstrated demonstratedthat thatthe thepresence presenceofofchromate chromatereductase reductase gene maltophilia, a fragment ofof around maltophilia, a fragment around468
The results indicate the possibility of employing chromate reductases of this kind minimizing oxidative stress
Summary
Cr is a heavy metal belonging to the transition group (VI-B) of the modern periodic table. Though, it exists in several oxidation states ranging from −2 to +6 due to its electronic structure, Cr(III) and. Cr(VI) is considered the most toxic form of Cr due to its strong oxidation potential, higher solubility in water, rapid permeability through biological membranes and it has recently been classified as one of the 17 most toxic chemicals by the Agency for Toxic Substances and Diseases Registry (ATSDR). Listed as grade ‘A’ human carcinogen by the United States Environmental Protection Agency (U.S EPA) [4,5]. Cr(VI) is a well-established occupational carcinogen associated with lung cancer and nasal and sinus cancer. NIOSH considers all Cr(VI) compounds to be occupational carcinogens
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
