Development of fluorescent whole-cell bacterial bioreporters for detection of inorganic arsenic and cadmium

Elçin, Evrim
Environmental heavy metal contamination in many regions of the world is a serious problem of ecological health. Fast and constant monitoring of their levels is significant for both preventing their accumulation and taking an immediate action for removal. As an alternative approach to standard laboratory techniques, various biosensor systems for detection of heavy metals have been proposed. Bacterial biosensors hold great promise for in-field detection of heavy metals. In this study, two different whole cell Escherichia coli bioreporter strains were developed for detection of inorganic arsenic and cadmium. In their presence, reporter gene expression increases which is detected as fluorescent signal later interpreted as a measure of available metal level in sample. Following cloning studies, arsenic and cadmium bacterial bioreporter strains were characterized for their metal specificity and detection limits by using different media and induction plans. In liquid assays, arsenic bioreporter could detect arsenite and arsenate at 10 μg/L after 2 hours, and cadmium bioreporter could detect cadmium of 2 μg/L after 1.5 hours of induction. Additionally, the arsenic bioreporter could estimate the bioavailable arsenic level in contaminated groundwater sample. To be integrated into a portable device, immobilization of arsenic bacterial bioreporter was investigated using agar and alginate biopolymers. Entrapment parameters of polymer concentration and cell density were evaluated. Immobilized cells were characterized for their metal specificity and detection limits by using different media. Agar and alginate immobilized bioreporter systems could detect arsenite and arsenate of 25 μg/L and 150 μg/L within 5 hours and 2 hours, respectively. The results demonstrated that these bacterial arsenic and cadmium bioreporter strains are applicable in determining the environmentally safe concentrations of these two most abundant heavy metals.


Inorganic Cadmium Detection Using a Fluorescent Whole-Cell Bacterial Bioreporter
Elcin, Evrim; Öktem, Hüseyin Avni (Informa UK Limited, 2020-11-01)
Cadmium pollution has become a serious environmental issue due to its toxicity and frequent entrance into environment components such as soil, water, and air via many anthropogenic sources. Over the last two decades, whole-cell bacterial bioreporters have been acknowledged as bio-sentinels for the determination of toxic heavy metals. Herein a sensitive and quite specific bacterial bioreporter was developed to cope with the need for the rapid and simple determination of cadmium. The construction and characte...
Assessment of PCB contamination, the potential for in situ microbial dechlorination and natural attenuation in an urban watershed at the East Coast of the United States
Kaya, Devrim; Sowers, Kevin R.; Demirtepe, Hale; Stiell, Brian; Baker, Joel E.; İmamoğlu, İpek; Kjellerup, Birthe (Elsevier BV, 2019-09-15)
Sediment contamination is a major environmental issue in many urban watersheds and coastal areas due to the potential toxic effects of contaminants on biota and human health. Characterizing and delineating areas of sediment contamination and toxicity are important goals of coastal resource management in terms of ecological and economical perspectives. Core and surficial sediment samples were collected from an industrialized urban watershed at the East Coast of the United Stated and analyzed to evaluate the ...
Quick Discrimination of Heavy Metal Resistant Bacterial Populations Using Infrared Spectroscopy Coupled with Chemometrics
Gurbanov, Rafig; Ozek, Nihal Simsek; Gözen, Ayşe Gül; Severcan, Feride (2015-10-06)
Lead and cadmium are frequently encountered heavy metals in industrially polluted areas. Many heavy metal resistant bacterial strains have a high biosorption capacity and thus are good candidates for the removal of toxic metals from the environment. However, as of yet there is no accurate method for discrimination of highly adaptive bacterial strains among the populations present in a given habitat. In this study, we aimed to find distinguishing molecular features of lead and cadmium resistant bacteria usin...
Characterization of lead-resistant river isolate Enterococcus faecalis and assessment of its multiple metal and antibiotic resistance
Aktan, Yasin; Tan, Sema; İçgen, Bülent (Springer Science and Business Media LLC, 2013-06-01)
Contamination of surface waters has a direct impact on the public health of entire communities. Microorganisms inhabiting contaminated surface waters have developed mechanisms of coping with a variety of toxic metals and drugs. Investigations were carried out to isolate and identify lead-resistant bacteria from the river KA +/- zA +/- lA +/- rmak along the city of KA +/- rA +/- kkale, Turkey. Of the 33 lead-resistant isolates, one isolate with a minimal inhibitory concentration of 1,200 mg L-1 was isolated ...
Molecular adaptations in cadmium and lead resistant environmental species
Kepenek, Eda Şeyma; Gözen, Ayşe Gül; Severcan, Feride; Department of Biology (2017)
Environmental pollution caused by heavy metal exposure has detrimental effects on human health. For the reclamation of polluted areas, bacteria have been used in remediation. For those bioremediation attempts, finding the appropriate bacterial strains is an important issue. In their environment, bacteria may exist close to the source of heavy metals. Sudden exposure to high concentrations of the heavy metal may trigger quick response mechanisms to ensure survival. On the other hand, bacteria may live at a d...
Citation Formats
E. Elçin, “Development of fluorescent whole-cell bacterial bioreporters for detection of inorganic arsenic and cadmium,” Thesis (Ph.D.) -- Graduate School of Natural and Applied Sciences. Biotechnology., Middle East Technical University, 2019.