10.25394/PGS.8984261.v1
Ioanna Koltsidou
Ioanna
Koltsidou
DETECTION AND QUANTIFICATION OF TASTE AND ODOR PRODUCING BACTERIA IN EAGLE CREEK RESERVOIR
Purdue University Graduate School
2019
geosmin
2-MIB
bacteria
qPCR
drinking water
geoA
MIBS
Bioinformatics
Freshwater Ecology
Molecular Biology
2019-10-16 17:11:56
Thesis
https://hammer.purdue.edu/articles/thesis/DETECTION_AND_QUANTIFICATION_OF_TASTE_AND_ODOR_PRODUCING_BACTERIA_IN_EAGLE_CREEK_RESERVOIR/8984261
<p>The accelerated growth of algal blooms in water bodies has
caused the increased occurrence of taste and odor (T&O) episodes worldwide.
Even though T&O compounds have not been associated with adverse health
effects, their presence can have extensive socio-economic impacts in
contaminated waters. Eagle Creek Reservoir, a eutrophic water body, which
supplies about 80% of Indianapolis drinking water, experiences frequent and
sometimes severe odorous outbreaks. The terpenoid bacterial metabolites,
2-methylisoborneol (2-MIB) and geosmin, have been identified as the main
compounds contributing to those T&O problems, which occur seasonally when
the reservoir receives most of its water and nutrient loads from discharge
events. In this study, ECR’s microbial community composition was assessed by a
16S next generation sequencing approach, confirming the presence of the major bacterial phyla of Cyanobacteria, Proteobacteria,
Actinobacteria and Bacteroidetes, which are commonly found in freshwater
environments. The relative abundance of Cyanobacteria, which are regarded as
the main T&O producers in freshwater, followed the fluctuation of 2-MIB and
geosmin concentrations closely. Mapping sequence analysis of a metagenomic
dataset, successfully recovered the genes responsible for the synthesis of
geosmin and 2-MIB, demonstrating the microbial ability for odorous compound
production in ECR. Quantification
of the <i>geoA </i>and <i>MIBS </i>genes in Cyanobacteria was achieved by the development and
application of qPCR assays on water samples collected from the reservoir. A
statistically significant positive correlation was found between <i>MIBS </i>gene quantity and MIB concentration
for all sampling locations, implying that this assay could potentially be used
as a tool for the early prediction of upcoming T&O episodes. The <i>geoA</i> gene detection assay, did not
correlate well with geosmin concentrations, suggesting that even though the
gene might be present, this does not necessarily mean that it is metabolically
active. </p>