Duetz-MTPS combined with HTS-FTIR spectroscopy biochemical profiling for high-throughput screenings of oleaginous microalgae

Microalgae are promising cell factories to produce valuable biochemicals such as lipids, proteins, polysaccharides, pigments, phytosterols and can be used for nutraceuticals, feed, biofuel, wastewater treatment and CO2 sequestration. Yet, the use of microalgae, in the aforementioned areas, struggles to go beyond research stage due to the complexity of process optimization. Optimization of microalgae production is a multi-step process and includes screening of strains and culture conditions, up-scale in bioreactors and downstream processing for extracting and fractionation. Screening of microalgae needs to be done in a high-throughput set-up and, currently, it is challenging as there are no high-throughput systems especially developed for screening of phototrophic microalgae. In this study we evaluated Duetz microtiter plate system (Duetz-MTPS) combined with HTS-FTIR spectroscopy as a high-throughput analytical platform for screening of microalgae for lipid production. Duetz-MTPS is a microtiter plate system which, when combined with HTS-FTIR, was successfully used for process optimization screenings of oleaginous yeast, filamentous fungi, heterotrophic algae and thraustochytrids ((Dzurendova et al. 2020; Kosa et al. 2017). Compared to traditional wet chemical analysis, fewer biomass is required for HTS-FTIR, while allowing to evaluate the total cellular biochemical profile including proteins, lipids and polysaccharides. In addition, it allows chemical-free and quick analysis. We used Scenedesmus sp. and Chlorella vulgaris to evaluate the suitability of Duetz-MTPS and HTS-FTIR for growth and lipid formation screening. For the control we grew both algae in flasks. Pearson correlation on different regions of the HTS-FTIR spectra has estimated to evaluate the variability for Duetz-MTPS (wells and plates) and flasks for both organisms. For flasks and Duetz-MTPS, the highest variability was found between days and species, while the lowest variability was found between triplicates. In between, variability between plates, flasks and wells was of the same order.