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Spermidine enhanced resistance of Chlorella to high levels of CO₂ and light intensity for improving photosynthetic growth rate

Zhang, Xiangdong, Cheng, Jun, Lu, Hongxiang, Chu, Feifei, Xu, Junchen, Wang, Xuebin, Cen, Kefa
RSC advances 2019 v.9 no.45 pp. 26495-26502
Chlorella, H+/K+-exchanging ATPase, H-transporting ATP synthase, biomass production, carbon dioxide, cell division, coal, electron transfer, energy, flue gas, fractal dimensions, light intensity, photosynthesis, power plants, spermidine, superoxide dismutase
In order to promote the photosynthetic growth rate of Chlorella in the presence of flue gas CO₂ from coal-fired power plants, spermidine was first used to enhance cellular resistance to a high CO₂ concentration (15%) and high light intensity (30 000 lux). It was found that low concentrations (100–300 μM) of spermidine significantly enhanced the photosynthetic growth rate of Chlorella. The accelerated cell division decreased the cell diameter from 3.64 μm to 2.71 μm and the fractal dimension from 1.60 to 1.49, and the activity of total superoxide dismutase (T-SOD) increased from 0.48 U mL⁻¹ to 5.33 U mL⁻¹. Expression levels of key enzymes of photosystems I and II, ATP synthase and transportase markedly increased, thereby enhancing the electron transport and energy supply that reduced oxidative damage. Finally, an enhanced cellular resistance to the high CO₂ concentration and high light intensity increased the biomass yield from 0.11 g L⁻¹ to 1.71 g L⁻¹ (300 μM).