Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Bioresour Technol. 2022 May;351:127009. doi: 10.1016/j.biortech.2022.127009. Epub 2022 Mar 15.
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 CO 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 CO 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 OD of 4.56, 21.32 mg/L and 672 mg/L using photo-bioreactor (PBR) with 5% CO. Moreover, CO assimilation rate was 2.748 g-CO/g-DCW and 2.792 g-CO/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.
莱茵衣藻是一种模式微藻，具有更高的生长速度，能产生高水平的叶黄素和脂类，但生物量生产受到限制。碳酸酐酶（CA）将大气中的 CO 转化为碳酸氢盐，这对微藻的碳浓缩机制（CCM）至关重要，并能提高细胞密度。因此，探索了含有来自根瘤菌（MlCA）和黄硫菌（SyCA）的异源 CA 的莱茵衣藻，以通过不同的培养设备提高 CO 的捕获和利用（CCU）。经过基因改造的莱茵衣藻能够从混养条件生长到自养条件。随后，在 5% CO 的光生物反应器（PBR）中，生物量、叶黄素和脂质分别最大化为 OD4.56、21.32mg/L 和 672mg/L。此外，在混养和自养条件下，CO 同化率分别为 2.748g-CO/g-DCW 和 2.792g-CO/g-DCW。生物量积累与 CA 活性相关。此外，叶黄素和脂质代谢途径的主要基因的转录水平显著增加。
