School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450000, China; Henan Key Laboratory of Water Environment Simulation and Treatment, Zhengzhou 450046, China; Henan Engineering Research Center of Water Pollution and Soil Damage Remediation, Zhengzhou 450046, China.
Civil and Environmental Engineering, University of Michigan, 2350 Hayward St, G.G. Brown Building, Ann Arbor, MI 48109, USA.
Bioresour Technol. 2019 Dec;294:122172. doi: 10.1016/j.biortech.2019.122172. Epub 2019 Sep 21.
Light intensity and photoperiod significantly affect Rhodopseudomonas palustris growth and pigments production and their optimization is necessary for pigment biosynthesis. In this study, the impacts of different light intensity and light/dark cycles were investigated on biomass, carotenoids, bacteriochlorophyll production, together with pollutant removal, in a photobioreactor system. Results showed that R. palustris had the highest carotenoids and bacteriochlorophyll productions with light intensity of 150 μmol-photons/m/s and light/dark cycle of 4/2 (16 h/8h). The corresponding values were 1.94 mg/g-biomass and 1.17 mg/g-biomass, respectively. The effects of light/dark cycle on crtA and bchE gene expression in pigments biosynthesis were also studied. Mechanism analysis revealed that carotenoids and bacteriochlorophyll yields represented good synergistic effect, which was consistent with the up-regulation of crtA and bchE gene expressions under optimal light/dark cycle of 4/2.
光强和光周期对沼泽红假单胞菌的生长和色素生产有显著影响，因此需要对其进行优化。本研究在光生物反应器系统中考察了不同光强和光照/黑暗周期对生物量、类胡萝卜素、细菌叶绿素生产以及污染物去除的影响。结果表明，在 150μmol-photons/m/s 的光强和 4/2（16h/8h）的光照/黑暗周期下，沼泽红假单胞菌的类胡萝卜素和细菌叶绿素产量最高，分别为 1.94mg/g-生物量和 1.17mg/g-生物量。还研究了光暗周期对色素生物合成中 crtA 和 bchE 基因表达的影响。机理分析表明，类胡萝卜素和细菌叶绿素的产率表现出良好的协同效应，这与最佳光暗周期 4/2 下 crtA 和 bchE 基因表达的上调一致。
