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Table 4 Effects of urea on growth and TAG content of C. gracilis

From: Advantageous characteristics of the diatom Chaetoceros gracilis as a sustainable biofuel producer

  Seawater Marine Art 1% NaCl-based media
F/2 Urea-F/2 F/2 + 70 ppm urea IMK IMK + 70 ppm urea F/2 Urea-F/2 F/2 + 70 ppm urea
Doubling time (h) 10.3 ± 0.1 8.93 ± 0.10 10.5 ± 0.1 10.2 ± 0.4 8.61 ± 0.25 9.16 ± 0.17 9.28 ± 0.16 9.63 ± 0.40
Cell density on 4th day (106 cells/mL) 4.72 ± 0.05 6.01 ± 0.16 6.36 ± 0.06 5.22 ± 0.22 5.67 ± 0.02 5.37 ± 0.37 5.36 ± 0.13 5.52 ± 0.10
Cell density on 10th day (106 cells/mL) 6.64 ± 0.01 7.04 ± 0.02 8.31 ± 0.18 6.73 ± 0.14 6.19 ± 0.05 6.59 ± 0.34 5.51 ± 0.22 7.08 ± 0.13
Volume-specific TAG on 10th day (mg/L) 163 ± 3 179 ± 9 150 ± 6 87.6 ± 5.3 76.6 ± 5.0 272 ± 4 260 ± 6 159 ± 15
Cell-specific TAG on 10th day (pg/cell) 24.1 ± 0.8 26.7 ± 2.6 18.0 ± 0.5 13.8 ± 1.1 11.9 ± 0.9 25.7 ± 1.9 47.4 ± 2.4 21.1 ± 2.1
  1. Cells cultivated in media enriched with F/2 without vitamins; urea-F/2 medium contained urea not nitrate at same molar concentration; F/2 + 70 ppm urea and IMK + 70 ppm urea media contained urea in addition to nitrate; 1% NaCl-based medium in place of seawater contained 1% NaCl and MgSO4, CaCl2, KCl, and NaHCO3 added, as described in “Methods” section; and n = 3