Microalgae have been extensively applied on bioremediation processes and biosorption is usually considered the main mechanism describing metal removal from wastewaters. Nevertheless, the water chemistry is modified during algal growth and the increase in both pH and oxygen concentrations result in metal precipitation. In this regard, the aim of the current study is to investigate how these two phenomena promote metal removal from waters, applying Chlorella vulgaris and high concentrations of manganese (50 mg/L)—one of the most common and difficult metals to be removed from fresh- and wastewaters alike. Triplicate experiments were carried out at 25 °C and 150 min⁻¹ under 24 h/day of artificial light and revealed that the growth of C. vulgaris was associated with a reduction in Mn²⁺ concentration to values below 1 mg/L, as the pH changed from 6.2 to 9.6, within 14 days. Biosorption as a removal mechanism appears not to be relevant as the manganese uptake by the C. vulgaris cells was actually reduced from 10.9 mg/g (10 min) to 0.9 mg/L, within 24 h of testing, indicating desorption of the manganese initially adsorbed. Furthermore, the formation of brown precipitates containing Mn³⁺/Mn⁴⁺ oxy-hydroxides was observed, which was confirmed upon reaction with leucoberbelin blue (LBB) solutions. In addition, no evidence of the participation of extracellular materials on Mn²⁺ removal was observed. These outcomes support the hypothesis that an increase in pH, resulting from the growth of C. vulgaris, is responsible for increasing pH to values above 8.0, values in which Mn²⁺ oxidation is catalysed.

微藻已广泛应用于生物修复过程，生物吸附通常被认为是废水中金属去除的主要机制。然而，水的化学性质在藻类生长过程中发生了变化，pH 值和氧气浓度的增加导致金属沉淀。在这方面，本研究的目的是研究这两种现象如何促进水中金属的去除，应用普通小球藻和高浓度的锰（50毫克/升）——最常见和最难去除的金属之一新鲜水和废水都一样。^{在 25°C、150 分钟-1}、每天 24 小时的人造光下进行三次重复实验，结果表明，普通念珠菌的生长与 Mn ²⁺浓度降低至低于 1 mg/L 的值相关，如14 天内，pH 值从 6.2 变为 9.6。生物吸附作为去除机制似乎并不相关，因为在测试的 24 小时内，普通念珠菌细胞对锰的吸收实际上从 10.9 mg/g（10 分钟）减少到 0.9 mg/L，表明锰最初解吸被吸附。^{此外，观察到含有Mn 3+} /Mn ⁴⁺羟基氧化物的棕色沉淀物的形成，这在与白小柏林蓝(LBB)溶液反应时得到证实。此外，没有观察到细胞外物质参与Mn ^{2+去除的证据。}这些结果支持这样的假设：由于普通念珠菌的生长导致 pH 值升高，导致 pH 值升高至 8.0 以上，此时 Mn ²⁺氧化被催化。