Enhanced carbon capture and utilization (CCU) using heterologous carbonic anhydrase in Chlamydomonas reinhardtii for lutein and lipid production

• Published in: Bioresource technology 2022-05, Vol.351, p.127009-127009, Article 127009
• Main Authors: Lin, Jia-Yi, Sri Wahyu Effendi, Sefli, Ng, I-Son
• Format: Article
• Language: English
• Subjects: Carbon - metabolism; Carbon Dioxide - metabolism; Carbonic anhydrase; Carbonic Anhydrases - genetics; Carbonic Anhydrases - metabolism; Chlamydomonas reinhardtii; Chlamydomonas reinhardtii - genetics; Chlamydomonas reinhardtii - metabolism; Lipid; Lipids; Lutein; Lutein - metabolism; Microalgae
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127009

[Display omitted] •The opportunity of heterologous carbonic anhydrase in CC-400 was evaluated.•This is the first attempt to cultivate CC-400 strain under autotrophic condition.•The carbon capture was achieved to 2.75 g-CO2/g-DCW in the optimal condition.•The biomass, lutein, and lipid were increased 2-, 4- and 8-folds in modified CC-400.•Transcriptional levels of major genes in the pathway decipher CA effect in CC-400. Chlamydomonas reinhardtii is a model microalga that has a higher growth rate and produces high levels of lutein and lipids, but biomass production is limited. Carbonic anhydrase (CA) converts atmospheric CO2 to bicarbonate which is crucial for carbon‐concentrating mechanism (CCM) in microalgae and boosts cell density. Therefore, C. reinhardtii harboring the heterologous CA from Mesorhizobium loti (MlCA) and Sulfurihydrogenibium yellowstonense (SyCA) were explored to increase CO2 capture and utilization (CCU) through different culture devices. Genetically modified C. reinhardtii was able to grow from mixotrophic to autotrophic conditions. Subsequently, biomass, lutein, and lipid were maximized to OD680 of 4.56, 21.32 mg/L and 672 mg/L using photo-bioreactor (PBR) with 5% CO2. Moreover, CO2 assimilation rate was 2.748 g-CO2/g-DCW and 2.792 g-CO2/g-DCW under mixotrophic and autotrophic conditions, respectively. The biomass accumulation correlated with CA activity. In addition, the transcript levels of major genes in metabolic pathways of lutein and lipid were dramatically increased.