Subcategory: Cell and Molecular Biology
Evan Richards - Texas A&M University
Co-Author(s): Alex Shammai, Nida Warsi, Hyun Soo Kim, Sergio Waqued, and Arum Han
Microalgae have higher productivity, a low environmental impact, and less competition with land usage and food compared to food based biofuel feedstocks, but production of microalgal biofuel is not economically viable. Optimization of microalgal culture conditions that results in increased growth and oil production will improve microalgae as an energy source. However, current testing systems are not fit to practically collect the wide dataset needed to study the optimized condition due to low throughput, large scale, and cost. Microfludic platforms can provide the high-throughput assay capabilities desirable for practically experiment with microalgae. Here, we present a high-throughput microfluidic platform with integrated temperature and nutrient gradient. The microfluidic platform is composed of three functional layers: a top microfluidic control layer, a middle microalgae culture layer with nutrient control, and a bottom temperature control layer. The top control layer has micro-scale valve structures which allows for opening and closing of the culture chambers in the underlying middle cell culture layer. The middle culture layer consists of arrays of culture chambers where microalgae can be isolated, cultured, and analyzed over time. A microfluidic gradient generator is utilized here where different nutrient combinations can be generated and provided into each culture chambers. The bottom layer has an array of 5 integrated electrodes having a different temperature resulting in a temperature gradient from 20 to 40°C across the microalgae culture/analysis layer. All of operations are controlled by an Arduino. The developed platform was successfully fabricated and is currently being used for characterization. Unicellular microalgae, Chlamydomonas reinhardtii, was isolated and cultured in the middle cell culture/ analysis layer, which showed similar growth profile compared to conventional flask cultures. Sixteen nutrient concentrations were successfully produced from the gradient generator. After, trends between growth and oil production rates and nitrogen concentration were observed. 0% nitrogen resulted in no growth and maximum oil production. At 100% nitrogen, algae growth was maximized and oil production ceased. Gradient of temperature is being tested and will be integrated in parallel with nutrient gradient control, which allows for high-throughput screening of microalgal growth and oil production under various nutrient and temperature conditions.
Funder Acknowledgement(s): This study was supported by a grant from NSF/EFRI-REM awarded to A. Han.
Faculty Advisor: Arum Han,