Abstract
Abstract Using saline-alkali leachate to cultivate microalgae is an effective way to realize the utilization of wastewater and alleviate the shortage of water resources. Light source is usually used as an optimized parameter to further improve the cultivation efficiency of microalgae. In this work, the influence of light qualities on the growth and high-valued substances accumulation of Chlorella sp. HQ in coastal saline-alkali leachate were investigated. The specific growth rate of Chlorella in coastal saline-alkali leachate was 0.27–0.60 d−1. At the end of cultivation, the algal density under blue light reached 8.71 ± 0.15 × 107 cells·mL−1, which was significantly higher than the other light groups. The lipid content in the biomass was 29.31–62.95%, and the highest lipid content and TAGs content were obtained under red light and blue-white mixed light, respectively. Percentages of total chlorophylls (0.81–1.70%) and carotenoids (0.08–0.25%) were obtained in the final biomass of the coastal saline-alkali leachate. In addition, the contents of photosynthetic pigments and three high-valued products under mixed light were higher than those of monochromatic light, and the protein, total sugar and starch content under blue-red mixed light was 1.52–3.76 times, 1.54–3.68 times and 1.06–3.35 times of monochromatic blue light and red light, respectively.
Highlights
Soil salinization is a widespread environmental problem worldwide, and there are approximately 954 million hectares of saline-alkali land in the world (Yue et al )
In order to improve the growth efficiency of Chlorella in coastal saline-alkali leachate, Light emitting diode (LED) lights with different light qualities were used as the light source for the growth of Chlorella
The results showed that the lipid content of Chlorella in the coastal saline-alkali leachate was 29.31–62.95%, and the value under red light was the highest, which was significantly higher than the blue light group and the blue-red mixed light group (p < 0.05)
Summary
Soil salinization is a widespread environmental problem worldwide, and there are approximately 954 million hectares of saline-alkali land in the world (Yue et al ). The improvement of saline-alkali land often adopts various methods such as physical restoration, chemical modification and bioremediation, and the common practiced method in the world is the combination of irrigation and drainage, which removes the salt in the soil through leaching (Wang et al ; Meena et al ). This method can improve the soil quality, it produces a large amount of wastewater with high salinity. Our previous studies have shown that the coastal saline-alkali leachate can be used to cultivate three oleaginous microalgae at low cost to realize the conversion of wastewater resources (Liu et al )
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