College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium.
College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Key Laboratory of Marine Environmental and Ecology, Ministry of Education, Ocean University of China, Qingdao, 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao, 266100, China.
J Environ Manage. 2022 Jan 15;302(Pt B):114095. doi: 10.1016/j.jenvman.2021.114095. Epub 2021 Nov 12.
Microalgae are one of the promising sources for renewable energy production, and the light intensity variation can affect the biofuel generation and carbon assimilation of mixotrophic microalgae. To reveal the response of carbon assimilation to light intensity, the effect of light intensity on the carbon source metabolism of Chlorella vulgaris under mixotrophic cultivation was investigated in this study. Moreover, the optimal carbon source composition for mixotrophic microalgae cultivation was evaluated using bicarbonate (HCO) and carbonate (CO) as inorganic carbon sources, and glucose and acetate as organic carbon sources. The optimal light intensity for Chlorella vulgaris growth was at the range of 8000-12000 lux. For the accumulation of biochemical components, low light intensity was beneficial to protein accumulation, and high light intensity was advantageous for carbohydrate and lipid accumulation. With HCO and glucose, the maximum lipid content reached 37.0% at a light intensity of 12000 lux. The citrate synthase activity was negatively correlated with light intensity, showing an opposite trend to biomass production. High light intensity had a positive impact on Rubisco expression, which promoted the microalgae growth and carbon fixing. The energy produced by heterotrophic metabolic activities increased at low light intensity, and the enhancement of biomass production with high light intensity was mainly caused by the improved photoreaction efficiency during the mixotrophic cultivation.
微藻是可再生能源生产的有前途的来源之一，光强变化会影响混合营养型微藻的生物燃料生成和碳同化。为了揭示碳同化对光强的响应，本研究考察了光强对混合培养条件下普通小球藻碳源代谢的影响。此外，还使用碳酸氢盐（HCO）和碳酸盐（CO）作为无机碳源，葡萄糖和醋酸盐作为有机碳源，评估了混合营养型微藻培养的最佳碳源组成。普通小球藻生长的最佳光强范围在 8000-12000 勒克斯之间。对于生化成分的积累，低光强有利于蛋白质积累，高光强有利于碳水化合物和脂质积累。在 HCO 和葡萄糖存在的情况下，当光强为 12000 勒克斯时，最大脂质含量达到 37.0%。柠檬酸合酶活性与光强呈负相关，与生物量生产呈相反趋势。高光强对 Rubisco 表达有积极影响，促进了微藻的生长和碳固定。异养代谢活动产生的能量在低光强下增加，高光强下生物量的增加主要是由于混合培养期间光反应效率的提高。
