Laboratory of Biochemistry. Faculty of Experimental Sciences. Marine International Campus of Excellence and REMSMA. University of Huelva, 210071 Huelva, Spain.
Department of Chemistry. Research Center in Technology of Products and Chemical Processes, PRO2TECS. University of Huelva. Campus el Carmen s/n 210071, Huelva, Spain.
Aquat Toxicol. 2021 Oct;239:105941. doi: 10.1016/j.aquatox.2021.105941. Epub 2021 Aug 19.
The chlorophyte microalga Chlorella sorokiniana was tested for the bioremediation of heavy metals pollution. It was cultured with different concentrations of Cu, Cd, As (III) and As (V), showing a significant inhibition on its growth at concentrations of 500 µM Cu, 250 µM Cd, 750 µM AsO and 5 mM AsO or higher. Moreover, the consumption of ammonium was also studied, showing significant differences for concentrations higher than 1 mM of Cu and As (III), and 5 mM of As (V). The determination of intracellular heavy metals concentration revealed that Chlorella sorokiniana is an outstanding Cd accumulator organism, able to accumulate 11,232 mg kg of Cd, and removing 65% of initial concentration of this heavy metal. Finally, antioxidant enzymes, such as catalase (CAT) and ascorbate peroxidase (APX), and enzymes involved in the production of glutamate and cysteine, such as glutamine syntethase (GS), glutamate dehydrogenase (GDH), O-acetylserine (thiol) lyase (OASTL) and NAD-isocitrate dehydrogenase (NAD-IDH) were studied both at gene expression and enzymatic activity levels. These enzymes exhibited different grades of upregulation, especially in response to Cd and As stress. However, GS expression was downregulated when Chlorella sorokiniana was cultured in the presence of these heavy metals.
小球藻被测试用于重金属污染的生物修复。它在不同浓度的 Cu、Cd、As（III）和 As（V）中培养，在 500µM Cu、250µM Cd、750µM AsO 和 5mM AsO 或更高浓度下，其生长受到显著抑制。此外，还研究了铵的消耗，发现 Cu 和 As（III）浓度高于 1mM，以及 As（V）浓度高于 5mM 时，差异显著。细胞内重金属浓度的测定表明，小球藻是一种出色的 Cd 积累生物，能够积累 11232mgkg 的 Cd，并去除初始浓度 65%的这种重金属。最后，研究了抗氧化酶，如过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX），以及与谷氨酸和半胱氨酸生成有关的酶，如谷氨酰胺合成酶（GS）、谷氨酸脱氢酶（GDH）、O-乙酰丝氨酸（硫）裂解酶（OASTL）和 NAD-异柠檬酸脱氢酶（NAD-IDH），在基因表达和酶活性水平上都进行了研究。这些酶表现出不同程度的上调，尤其是在应对 Cd 和 As 胁迫时。然而，当小球藻在这些重金属存在的情况下培养时，GS 的表达被下调。
