Raoultella ornithinolytica as a Potential Candidate for Bioremediation of Heavy Metal from Contaminated Environments

• Published in: Journal of microbiology and biotechnology Vol. 33; no. 7; pp. 895 - 908
• Main Authors: Salih, Laila Ibrahim Faqe, Rasheed, Rezan Omer, Muhammed, Sirwan Muhsin
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Society for Microbiology and Biotechnology 28-07-2023; 한국미생물·생명공학회
• Subjects: Biodegradation, Environmental; Cadmium; Environmental Monitoring; Humans; Lead; Metals, Heavy - chemistry; Research article; RNA, Ribosomal, 16S; 생물학; Raoultella ornithinolytica; metal uptake; Bioremediation; heavy metals; tolerance
• ISSN: 1017-7825; 1738-8872
• DOI: 10.4014/jmb.2212.12045

Disposal of waste containing heavy metals into the environment is a major threat to human health and can result in toxic or chronic poisoning in aquatic life. In the current study, metal-resistant
was isolated from metal-contaminated samples collected from the Tanjaro River, located southwest of Sulaymaniyah, Iraq.
was identified by partial amplification of 16S rRNA. The uptake potency of heavy metals was assessed using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and indicated that
removed 67, 89, 63.4, 55.6, 56.5, 65, and 61.9% of Cd, Pb, Cr, Ni, Zn, Co, and Fe, respectively. These removal rates were influenced by temperature, pH, and contact time; at 35°C and pH 5 with a change in the incubation time, the reduction rate improved from 89 to 95% for Pb, from 36.4 to 45% for Cu, and from 55.6 to 64% for Ni. Gene analysis indicated that
contained
,
,
,
, and
genes, but the
gene was absent. Energy-dispersive X-ray spectroscopy (EDS) images showed evidence of metal ion binding on the cell wall surface with different rates of binding. Transmission electron microscopy (TEM) detected different mechanisms for metal particle localization; cell surface adsorption was the main mechanism for Pb, Zn, and Co uptake, while Cd, Ni, and Fe were accumulated inside the cell. The current study describes, for the first time, the isolation of
from metal-contaminated water, which can be used as an eco-friendly biological expedient for the remediation and detoxification of metals from contaminated environments.