In this study, we propose the use of competitive adsorption technology and a novel carbon-based aptamer biosensor as effective methods for the evaluation and removal of off-flavor compounds from Recirculating Aquaculture Systems (RAS). Waxes have proven to be effective in adsorption of hydrophobic compounds, an example being the highly common off-flavor compound geosmin. Soybean wax beads and cylinders were immersed in geosmin-spiked water. The water and wax were evaluated for geosmin concentration at regular intervals and collected data was aggregated to determine the diffusivity and partitioning constant of soybean wax and geosmin molecules in water.

 

Detection of off-flavor compounds may also be streamlined by a proposed inexpensive carbon-based biosensor. The immobilization of aptamers on a field effect transistor (FET) allows for instantaneous detection of geosmin in concentrations as low as .01 nM. This biosensor offers many advantages, being low-cost relative to other testing methods, having better ease of use, and providing instantaneous results, high affinity to a specific substrate, and no careful maintenance.​

 

My research partner, Mason, focused more on the aptamer biosensor part of this study while I focused more on the soybean wax competitive adsorption technology part.

 

As mentioned before, our set up of soybean wax in geosmin-spiked water was in three-dimensional shapes. The wax cylinder was created by filling a glass with soybean wax and creating a positive meniscus so that when the wax was dried, a completely flat surface could be created. This created a singular face of wax in the cylinder. This cylinder was submerged in a tank of 500 μg/L geosmin-spiked water along with a stir bar to replicate a continuous stirred-tank reactor (what a RAS system is). Samples of