@article{karam_lai_reyes_ducoste_2021, title={Chlorophyll a and non-pigmented biomass are sufficient predictors for estimating light attenuation during cultivation of Dunaliella viridis}, volume={55}, ISSN={["2211-9264"]}, url={https://publons.com/wos-op/publon/46639302/}, DOI={10.1016/j.algal.2021.102283}, abstractNote={Characterizing light in microalgal cultivation vessels is needed for modeling and optimizing microalgal growth for large-scale cultivation. Dynamic changes in light intensity over space due to geometry, refraction/reflection, and the interactive impacts of algal growth and their biocomponents with light make this characterization challenging. Understanding which biocomponents within microalgal cultures are key variables in accurately estimating light attenuation is fundamentally important, yet, inconsistent and wide-ranging applications of the Beer-Lambert law are often used to estimate light attenuation. This research rigorously evaluated which biocomponents (total biomass, cell count, and chl a, chl b, and total photosynthesizing pigments), or biocomponent combinations, serve as best predictors for light attenuation when modeling with the Beer-Lambert law. Calibration and validation experiments were performed using salt-water species Dunaliella viridis microalgal cultures grown in 3-L flat-plate PBRs with continuous light monitoring. Results at the various light and nitrogen levels tested showed Beer-Lambert's law predicted photosynthetic light attenuation well when both biomass and chlorophyll a were considered as distinct attenuating components, providing light estimates with less than 6% error on average over validation experiments. If the model included only one component as a predictor for attenuation, pigments were best, with a 20% error in estimating light, as compared to ~70%, 60%, 40% for models that used solely biomass, cells, or chlorophyll a as an attenuating component., respectively. These results suggest that when using the Beer-Lambert's law to estimate photosynthetic light attenuation in microalgal cultures, both a chlorophyll a and biomass component should be consistently included.}, journal={ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS}, author={Karam, Amanda L. and Lai, Yi-Chun and Reyes, Francis L. I. I. I. I. I. I. and Ducoste, Joel J.}, year={2021}, month={May} } @article{karam_de los reyes_ducoste_2018, title={Development of Photochemical Microsensors for Evaluating Photosynthetic Light Dose Distributions in Microalgal Photobioreactors}, volume={52}, ISSN={0013-936X 1520-5851}, url={http://dx.doi.org/10.1021/acs.est.8b02056}, DOI={10.1021/acs.est.8b02056}, abstractNote={We describe the development and testing of a Lagrangian method for quantifying light dose distributions within photobioreactors (PBRs) using novel photochemical microsensors. These microsensors were developed using 3-μm microspheres coated with a fluorescent dye that responds to wavelengths of visible light that are critical for photosynthesis. The dose-response kinetics of the microsensors was established by varying known doses of collimated light and quantifying the fluorescence responses of individual particles using flow cytometry. A deconvolution scheme was used to determine the light dose distribution from the fluorescence distribution of the microsensors. As proof-of-concept, the microsensors were used to quantify the photosynthetic light dose distributions within a gently mixed, 3 L flat-plate, batch PBR with and without algae and no gas bubbling and without algae but with gas bubbling. The microsensor approach not only provided information about the photosynthetic light distributions within the PBRs but also predicted the average light attenuation due to algal cells within 1% of estimates made with an in situ light sensor. The results showed that bubbles, under the conditions tested, increased the overall light irradiance by 18%; a result not captured by static measurements. The Lagrangian microsensors provide a novel approach for quantifying light within a photobioreactor.}, number={21}, journal={Environmental Science & Technology}, publisher={American Chemical Society (ACS)}, author={Karam, Amanda L. and de los Reyes, Francis L., III and Ducoste, Joel J.}, year={2018}, month={Sep}, pages={12538–12545} } @article{karam_mcmillan_lai_reyes_sederoff_grunden_ranjithan_levis_ducoste_2017, title={Construction and setup of a bench-scale algal photosynthetic bioreactor with temperature, light, and ph monitoring for kinetic growth tests}, DOI={10.3791/55545-v}, abstractNote={The optimal design and operation of photosynthetic bioreactors (PBRs) for microalgal cultivation is essential for improving the environmental and economic performance of microalgae-based biofuel production. Models that estimate microalgal growth under different conditions can help to optimize PBR design and operation. To be effective, the growth parameters used in these models must be accurately determined. Algal growth experiments are often constrained by the dynamic nature of the culture environment, and control systems are needed to accurately determine the kinetic parameters. The first step in setting up a controlled batch experiment is live data acquisition and monitoring. This protocol outlines a process for the assembly and operation of a bench-scale photosynthetic bioreactor that can be used to conduct microalgal growth experiments. This protocol describes how to size and assemble a flat-plate, bench-scale PBR from acrylic. It also details how to configure a PBR with continuous pH, light, and temperature monitoring using a data acquisition and control unit, analog sensors, and open-source data acquisition software.}, number={124}, journal={Jove-Journal of Visualized Experiments}, author={Karam, A. L. and McMillan, C. C. and Lai, Y. C. and Reyes, F. L. and Sederoff, H. W. and Grunden, A. M. and Ranjithan, R. S. and Levis, J. W. and Ducoste, J. J.}, year={2017} }