Metabolic Analysis of Schizochytrium Mutants With High DHA Content Achieved With ARTP Mutagenesis Combined With Iodoacetic Acid and Dehydroepiandrosterone Screening

Lei Zeng; Yanqi Bi; Pengfei Guo; Yali Bi; Tiantian Wang; Liang Dong; Fangzhong Wang; Lei Chen; Weiwen Zhang

doi:10.3389/fbioe.2021.738052

Metabolic Analysis of Schizochytrium Mutants With High DHA Content Achieved With ARTP Mutagenesis Combined With Iodoacetic Acid and Dehydroepiandrosterone Screening

Front Bioeng Biotechnol. 2021 Nov 18:9:738052. doi: 10.3389/fbioe.2021.738052. eCollection 2021.

Authors

Lei Zeng^{1

2

3}, Yanqi Bi^{1

2

3}, Pengfei Guo^{1

2

3}, Yali Bi^{1

2

3}, Tiantian Wang^{1

2

3}, Liang Dong^{1

2

3}, Fangzhong Wang^{1

4}, Lei Chen^{1

2

3}, Weiwen Zhang^{1

4

2

3}

Affiliations

¹ Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, China.
² Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (MOE), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.
³ SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China.
⁴ Center for Biosafety Research and Strategy, Tianjin University, Tianjin, China.

Abstract

High DHA production cost caused by low DHA titer and productivity of the current Schizochytrium strains is a bottleneck for its application in competition with traditional fish-oil based approach. In this study, atmospheric and room-temperature plasma with iodoacetic acid and dehydroepiandrosterone screening led to three mutants, 6-8, 6-16 and 6-23 all with increased growth and DHA accumulations. A LC/MS metabolomic analysis revealed the increased metabolism in PPP and EMP as well as the decreased TCA cycle might be relevant to the increased growth and DHA biosynthesis in the mutants. Finally, the mutant 6-23, which achieved the highest growth and DHA accumulation among all mutants, was evaluated in a 5 L fermentor. The results showed that the DHA concentration and productivity in mutant 6-23 were 41.4 g/L and 430.7 mg/L/h in fermentation for 96 h, respectively, which is the highest reported so far in literature. The study provides a novel strain improvement strategy for DHA-producing Schizochytrium.

Keywords: ARTP mutagenesis; DHA; dehydroepiandrosterone; iodoacetic Acid; metabolomic analysis; schizochytrium.