过表达Na,K-ATPase基因增强了黑曲霉对硅灰石的风化能力

Overexpression of Na, K-ATPase gene enhanced the weathering ability of Aspergillus niger to wollastonite

摘要:

[目的]探究和证实黑曲霉钠钾ATP酶（NKA）在硅灰石风化过程中的作用。[方法]以野生型黑曲霉（WT）为原始菌株构建黑曲霉Na，K-ATPase α1基因（NKAα1）高表达菌株oeNKA。通过测定不同时间点（0 d、2 d、4 d、6 d）oeNKA和WT生物量、培养液pH值和矿物风化释放的Ca²⁺浓度，并用X-ray diffraction（XRD）对风化后的矿物残渣进行检测，比较oeNKA和WT菌株对硅灰石这种硅酸盐矿物的风化效果。[结果]oeNKA菌株的NKAα1基因相对表达量和酶活分别为WT菌株的103倍和1.76倍。在持续6 d的培养过程中，oeNKA与WT的菌丝体生物量变化趋势相同，在培养第2天时WT显著高于oeNKA，随时间差异逐渐缩小并在第6天达到最低；培养液pH值变化趋势相同，分别下降至3.64和3.87；oeNKA风化硅灰石时所释放Ca²⁺浓度（1011.36±47.78μg/g）约为WT（248.30±25.21 μg/g）的4倍；XRD检测图谱显示菌株oeNKA对硅灰石风化作用更明显。[结论]NKAα1过表达菌株oeNKA对硅灰石的风化能力显著高于WT菌株，且黑曲霉的NKA与硅灰石的风化有密切关联。

Abstract:

[Objective] To investigate and confirm the role of Na, K-ATPase (NKA) of Aspergillus niger in the weathering process of wollastonite, a silicate mineral. [Methods] Wild type Aspergillus niger was used as the original strain to construct high Na, K-ATPase α1 (NKA α1) gene-expressing strain oeNKA. We determined the biomass of oeNKA and the wild strain, pH of the culture medium and Ca²⁺ concentration released from wollastonite at different cultivation time (0, 2, 4 and 6 d). Besides, we also analyzed the mineralogy of the wollastonite residue by X-ray diffraction (XRD) to compare the weathering effect of oeNKA and the wild strain on wollastonite. [Results] The relative expression of NKA α1 and enzyme activity of oeNKA strain was 103 and 1.76 times higher than those of the wild strain, respectively. The biomass and pH of oeNKA had the same variation tendency as the wild strain during the 6-day cultivation. The biomass difference between the wild strain and oeNKA decreased significantly on the 2nd day, and then was gradually narrowed down over time and reached the lowest on the 6th day. Furthermore, the concentration of Ca²⁺ (1011.36±47.78 μg/g) released from wollastonite was about 4 times as that from the wild strain (248.30±25.21 μg/g). Moreover, the XRD pattern also showed that oeNKA exhibited intense effect on wollastonite weathering. [Conclusion] The weathering ability of oeNKA to wollastonite was significantly higher than that of the wild strain, and Na, K-ATPase in Aspergillus niger was actively involved in wollastonite weathering.