嗜中高温嗜酸古菌Ferroplasma thermophilum的培养条件优化

Optimization of Culture Condition of a Moderately Thermophilic Acidophilic Ferroplasma thermophilum

摘要:

在中高温和较低pH条件下, Ferrroplasma spp. 是进行硫化矿生物浸出的重要微生物。Ferroplasma spp.为古菌,无细胞壁, 对矿浆浓度、搅拌剪切力以及溶液中的重金属离子等敏感, 很难得到高密度的纯培养, 给大规模的工业应用带来了一定难度。研究了F. thermophilum摇瓶培养时的最佳生长条件, 单因素考察结果表明最适培条件为: 温度50oC, 初始pH 0.5, 250 mL的摇瓶装液量为50 mL, 无机氮源(NH4)2SO4。通过正交试验确定了FeSO4·7H2O、酵母粉和蛋白胨最适组合为FeSO4·7H2O 40 g/L, 酵母粉0.3 g/L, 蛋白胨0.2 g/L。优化培养后, F. thermophilum 浓度达到了6.3×107个/mL, 40 g/L的FeSO4·7H2O在72 h内全部氧化完全。该结果可为该类古菌的扩大培养以及工业应用提供参考。

Abstract:

The extreme microorganisms Ferroplasma spp., play an important role in bioleaching of sulphide ores at low pH value and temperatures around 50oC. Without cell wall, Ferroplasma spp. is sensitive to pulp density, shearing force and heavy metal ions. Thus it is difficult to obtain their high cell density cultures, which limits the large-scale industrial application. In this paper, the optimum culture conditions of Ferroplasma thermophilum were studied by shaking culture. The results showed that the optimum culture conditions are as follows: 50oC, initial pH 0.5, 50 mL working volume in 250 mL shaking-flask, inorganic nitrogen source (NH4)2SO4. The optimum combination of FeSO4·7H2O, yeast extract and peptone was determined by orthogonal experiments, including FeSO4· 7H2O 40 g/L, yeast extract 0.3 g/L, peptone 0.2 g/L. Under the optimum culture conditions, the cell density was up to 6.3×107 cell/mL, and the oxidation of 40 g/L ferrous sulfate heptahydrate was finished in less than 72 hours. The results might provide information for scale-up of archaeon culture as well as its industrial application.