Frontiers in Microbiology (Mar 2022)

Rewiring the Metabolic Network to Increase Docosahexaenoic Acid Productivity in Crypthecodinium cohnii by Fermentation Supernatant-Based Adaptive Laboratory Evolution

  • Liangsen Liu,
  • Liangsen Liu,
  • Liangsen Liu,
  • Jinjin Diao,
  • Jinjin Diao,
  • Jinjin Diao,
  • Yali Bi,
  • Yali Bi,
  • Yali Bi,
  • Lei Zeng,
  • Lei Zeng,
  • Lei Zeng,
  • Fangzhong Wang,
  • Fangzhong Wang,
  • Fangzhong Wang,
  • Fangzhong Wang,
  • Lei Chen,
  • Lei Chen,
  • Lei Chen,
  • Weiwen Zhang,
  • Weiwen Zhang,
  • Weiwen Zhang,
  • Weiwen Zhang,
  • Weiwen Zhang

DOI
https://doi.org/10.3389/fmicb.2022.824189
Journal volume & issue
Vol. 13

Abstract

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Docosahexaenoic acid (DHA, 22:6n-3) plays significant roles in enhancing human health and preventing human diseases. The heterotrophic marine dinoflagellate Crypthecodinium cohnii is a good candidate to produce high-quality DHA. To overcome the inhibition caused by the fermentation supernatant in the late fermentation stage of DHA-producing C. cohnii, fermentation supernatant-based adaptive laboratory evolution (FS-ALE) was conducted. The cell growth and DHA productivity of the evolved strain (FS280) obtained after 280 adaptive cycles corresponding to 840 days of evolution were increased by 161.87 and 311.23%, respectively, at 72 h under stress conditions and increased by 19.87 and 51.79% without any stress compared with the starting strain, demonstrating the effectiveness of FS-ALE. In addition, a comparative proteomic analysis identified 11,106 proteins and 910 differentially expressed proteins, including six stress-responsive proteins, as well as the up- and downregulated pathways in FS280 that might contribute to its improved cell growth and DHA accumulation. Our study demonstrated that FS-ALE could be a valuable solution to relieve the inhibition of the fermentation supernatant at the late stage of normal fermentation of heterotrophic microalgae.

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