How to narrow the CO2 gap from growth-optimal to flue gas levels by using microalgae for carbon capture and sustainable biomass production
How to narrow the CO2 gap from growth-optimal to flue gas levels by using microalgae for carbon capture and sustainable biomass production
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DOI：
10.1016/j.jclepro.2020.124448
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发表时间：
2021-01-20
影响因子：
11.1
通讯作者：
Xu, Changan
中科院分区：
文献类型：
--
作者：
Chen, Yimin;Xu, Changan
微藻可以作为一种“绿色生物清洁剂”，用于减少碳排放并同时生产可持续生物质，特别是在将烟气作为富碳源的情况下。然而，从增长最佳水平（2-6%）到烟气水平（10-25%）之间存在二氧化碳差距。为了缩小这一差距，本研究测试了几种气体控制策略，包括持续升高的CO2水平，去除O-2，逐渐增加CO2浓度，以及通过调整CO2剂量来控制pH值。结果表明，将CO2浓度从环境水平提高到6%（空气中）可以促进盐杜氏藻的生长，而将CO2浓度进一步提高到20%（空气中）则会显著抑制盐杜氏藻的生长。通过去除进口气体中的O-2，可将空气中CO2含量为20%时的CO2固定能力提高2.7倍，通过逐渐增加CO2浓度可进一步提高2.5倍，总体提高6.6倍。极高的CO2浓度（100%）完全抑制了生长，但通过及时切换空气曝气可以恢复这种负面影响。过量CO2的生长抑制与培养基酸化和色素减少有关，并伴有碳水化合物减少和轻微的脂质积累。当使用烟气作为碳源时，通过调整CO2投加量来控制pH值对于避免溶解无机碳和pH值的剧烈变化非常重要。(C) 2020 Elsevier Ltd。版权所有。
Microalgae can serve as a 'green bio-cleanser' for carbon mitigation and simultaneous production of sustainable biomass, especially when using the flue gas as a carbon-rich source. However, there is a CO2 gap from the growth-optimal (2-6%) to the flue gas (10-25%) levels. To narrow this gap, several gas manipulation strategies have been tested in this study, including constant elevated CO2 levels, O-2 removal, gradual increases in CO2 concentration, and pH control by adjusting the CO2 dosing. Results show that the growth of Dunaliella salina could be enhanced by increasing CO2 from the ambient level to 6% (in air) but was significantly inhibited by the further increase to 20% CO2 (in air). The CO2 fixation capacity at 20% CO2 in air could be improved by 2.7-fold via O-2 removal from the inlet gas, which could be further improved by 2.5-fold through gradual increases in CO2 concentration, reaching an overall enhancement of 6.6-fold. Extremely high CO2 concentration of 100% completely inhibited the growth, but the negative effect could be recovered by timely switch to air-aeration. Growth inhibition by excess CO2 was associated with the medium acidification and pigment reduction, accompanied by a decrease of carbohydrates and slight lipid accumulation. When using the flue gas as a carbon source, pH control by adjusting the CO2 dosing is important to avoid dramatic changes in both dissolved inorganic carbon and pH. (C) 2020 Elsevier Ltd. All rights reserved.