Mina Li, Kayla Sohn, Anika Strite, Hannah Kwa, Jay Bhasin, Akash Prabhakar Supervised by Cristianna Colella (Queens College CUNY) and Oskar Pineno (Hofstra University)
Conclusion
Introduction
Materials
• A photobioreactor is a specialized apparatus capable of utilizing light to cultivate phototrophic microorganisms by simulating the ideal conditions in which they naturally grow. • Our team designed and implemented an open system photobioreactor automated using an Arduino microcontroller to cultivate the cyanobacterium, A. Platensis (common name Spirulina), a prokaryote with various uses in clinical practice, including modulating immune functions, and nutrient supplementation. • Our open system design allows for circulation of necessary atmospheric gasses required for the culture to synthesize nutrients, and automated agitation of the reactor for resuspension of microorganisms. • The photobioreactor also utilizes light emitting diodes (LEDs) as a light source and an alkaline growth substance with a nutrient broth, all while incorporating a temperature probe to monitor the ideal growth temperatures of Spirulina. • Utilizing both custom 3D printed materials and household items controlled using an Arduino Uno microcontroller to automate culturing operations, we sought to create a scalable, affordable tabletop photobioreactor.
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Figure 1: Final mini photobioreactor prototype.
Design/Setup • The temperature probe rests inside the bioreactor and connects to the bread board. • An LED is placed through the bottom of the base and connects to the bread board. • The base is a 3D-print consisting of a platform with four rods to hold the bioreactor in place. The base is placed on a CD player and rests on ball bearings. • The platform has 2 screws with a rubber band between them. The rubber band is connected to the Servo motor and controls the agitation rate.
Figure 2: Arduino UNO wiring setup.
Code
For the mini photobioreactor, we created code for the agitator, LEDs, and temperature probe. Temperature Probe: The temperature probe used the serial monitor to print temperature values in both Celsius and Fahrenheit. This permits the monitoring of conditions of the Spirulina to ensure it was cultured at an optimal temperature
Figure 3: Computer-assisted design of custom 3D printed base.
• Using an Arduino Uno board to construct a photobioreactor is an inexpensive and eco-friendly way to grow sources of protein and nutrients at home. • Though our original design included many non-essential operations to optimize growth, our ultimate design included only essential elements, was entirely automated, low-cost and fully functional. • In the future, other enhancements can be added to optimize growth, including: the addition of a pH sensor, utilization of the temperature probe to be used as a sensor to control a heat lamp, and a CO2 probe can also be used to inform and modulate the agitation rate. • Further improvement on our design might entail testing samples of Spirulina and modifying this prototype to include other design factors to maximize growth and improve scalability. • Future applications include biofertilization, biofuel cultivation, and pollution treatment methods (environmental bioremediation) using organisms like algae and microalgae. • Though our mini photobioreactor prototype was engineered to cultivate small volumes of the cyanobacterium Spirulina, which is used predominantly for food and nutrient supplementation, our model can be feasibly scaled up to address such environmental issues.
Glass bottle vessel LEDs Servo motor Custom 3D-printed base Springs Rubber band Temperature sensor Ball bearings Culture medium Spirulina culture
Agitator: The Servo motor was coded in a loop to move to 100 degrees, pause for 5 milliseconds, then move to 0 degrees.
Mini Photobioreactor
LEDs: LEDs were placed under the glass bottle to illuminate throughout and provide adequate lighting for the Spirulina. We created a piece of code to alternate blue, green, and white LEDs.
References 1.
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Amaral, M. S., Loures, C. C.A., Naves, F. L., Baeta, B.E. L., Silva, M. B., & Prata, A.M. R. (2020). Evaluation of cell growth performance of microalgae chlorella minutissima using an internal light integrated photobioreactor. Journal of Environmental Chemical Engineering. Erbland, P., Caron, S., Peterson, M., & Alyokhin, A. (2020). Design and performance of a low-cost, automated, large-scale photobioreactor for microalgae production. Aquacultural Engineering. Nwoba, E. G., Parlevliet, D. A., Laird, D. W., Alameh, K., & Moheimani, N. R. (n.d.). Pilot-scale self-cooling microalgal closed photobioreactor for biomass production and electricity generation. Algal Research.