Non-axenic culture of Nitzschia palea enriched from a pond in Salar de Huasco Metagenome
Diatoms play an important role as primary producers, thriving in natural polyextreme environments such as high-altitude wetlands, where their ecology is poorly understood. In this study, the diatom Nitzschia palea was isolated from Salar de Huasco, Chile, a high-altitude wetland located at 3800 m above sea level. The culture was maintained at 17C under cool-white fluorescent light with a 14:10 (light:dark) photoperiod and a photon flux of 50 micromol photons sq meters per second. Scanning electron microscopy and a genomic approach were employed to identify this microalga as a new Nitzschia palea strain. Photophysiological responses were measured along with a series of media and temperature conditions in N. palea cultures.Modified f/2 media supplemented with various concentrations of Si, Se, and vitamins were tested. Subsequently, growth in the double-Si f/2 media was assessed at three different temperatures. Lastly, the diatom cultures were incubated at 17C and 27-29C in f/2 + double-Si (NN: Non-extra nutrient addition) and a highly eutrophic state of f/2 (WN: with nutrient enrichment addition). The highest growth was observed using the f/2 media WN at 17C (day 5, 4.46 x 10^5 +- 3.15 x 10^4 SD cells per mL). N. palea photophysiological responses were correlated with its high photoacclimation capacity and maximal quantum yield of PSII. Finally, its productivity and photosynthetic efficiency increased throughout the trial period using the f/2 media WN.