Research
| Title： | Knockdown of carbonate anhydrase elevates Nannochloropsis productivity at high CO2 level |
|---|---|
| First author： | Wei, Li; Shen, Chen; El Hajjami, Mohamed; You, Wuxin; Wang, Qintao; Zhang, Peng; Ji, Yuetong; Hu, Hanhua; Hu, Qiang; Poetsch, Ansgar; Xu, Jian |
| Journal： | METABOLIC ENGINEERING |
| Years： | 2019 |
| DOI： | 10.1016/j.ymben.2019.03.004 |
| Abstract： | Improving acid tolerance is pivotal to the development of microalgal feedstock for converting flue gas to biomass or oils. In the industrial oleaginous microalga Nannochloropsis oceanica, transcript knockdown of a cytosolic carbonic anhydrase (CA2), which is a key Carbon Concentrating Mechanism (CCM) component induced under 100 ppm CO2 (very low carbon, or VLC), results in similar to 45%, similar to 30% and similar to 40% elevation of photosynthetic oxygen evolution rate, growth rate and biomass accumulation rate respectively under 5% CO2 (high carbon, or HC), as compared to the wild type. Such high-CO2-level activated biomass over-production is reproducible across photobioreactor types and cultivation scales. Transcriptomic, proteomic and physiological changes of the mutant under high CO2 (HC; 5% CO2) suggest a mechanism where the higher pH tolerance is coupled to reduced biophysical CCM, sustained pH hemostasis, stimulated energy intake and enhanced photosynthesis. Thus inactivation of CCM can generate hyper-CO2-assimilating and autonomously containable industrial microalgae for flue gas-based oil production. |
