Abstract

Taste-and-odor (T&O) compounds are frequently produced by cyanobacterial blooms in bodies of water. Geosmin, perhaps the most common T&O compound produced by these blooms, is not effectively removed by conventional water treatment processes and frequently causes the tap water to have an off flavor. Although geosmin is not harmful when ingested, it damages the consumers' confidence in the cleanliness of their water. There are treatment options for geosmin removal, but the most common methods are often not implemented until complaints are made by consumers.There has been an increasing amount of research on the use of polymerase chain reaction (PCR)-based methods that can detect the presence of the geosmin synthase gene which is responsible for the production of geosmin. If the geosmin synthase gene is found to be present in an emerging cyanobacterial bloom, water treatment facilities can prepare in advance to treat for geosmin. In this study, we developed a qPCR (quantitative polymerase chain reaction) assay that can detect the presence of the geosmin synthase gene in several species of cyanobacteria within the Anabaena genus. We tested our assay, as well as PCR assays designed by Giglio et al. (2008) and Suurnäkki et al. (2015) on extracted Anabaena flos-aquae DNA, biosynthesized Anabaena ucrainica DNA and DNA extracted from environmental samples of Deer Creek Reservoir, Strawberry Reservoir, and Utah Lake. It is important to note that the geosmin gene was not confirmed to be present in any of the environmental samples nor in the Anabaena flos-aquae DNA and our assay did not test positive on these samples. Our qPCR assay was very successful when used with the biosynthesized Anabaena ucrainica DNA. We used the results to estimate a DNA standard curve that can be used to estimate the starting concentration of the geosmin synthase gene. Because our assay was not successfully used with any extracted DNA, further testing and calibration may be necessary to produce a DNA standard curve that is representative of DNA that is extracted. Further calibration of the DNA standard curve was not done because there were no geosmin events during the course of the research.Development of PCR-based methods of detecting geosmin-producing cyanobacteria requires genetic sequencing information of the target-organisms. Thus, further development of PCR-based methods requires that the local geosmin-producers be identified and sequenced. Our assay as well as the assay designed by Moore (2019) can assist with the identification of these species by classifying their genus.

Degree

College and Department

Ira A. Fulton College of Engineering and Technology; Civil and Environmental Engineering

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