Microbial release of potassium from K-bearing minerals by thermophilic fungus Aspergillus fumigatus
Microbial release of potassium from K-bearing minerals by thermophilic fungus Aspergillus fumigatus
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DOI：
10.1016/j.gca.2007.10.005
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发表时间：
2008
影响因子：
5
通讯作者：
B. Lian;Bin Wang;Mu Pan;Congqiang Liu;H. Teng
中科院分区：
文献类型：
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作者：
B. Lian;Bin Wang;Mu Pan;Congqiang Liu;H. Teng
将嗜热真菌烟曲霉菌株与含钾矿物一起培养，以确定微生物-矿物相互作用是否增强矿物钾的释放。实验在两种环境中进行，一种是矿物颗粒和真菌细胞直接接触，另一种是使用膜（孔径为0.22μm）将两者分开。在30天的时间内的测量表明，无论实验设置，在文化中的游离K的浓度是显着高于在任何控制实验中，没有活的生物体存在。此外，矿物细胞的物理接触的发生增强钾的释放由3至4的额外的因素相比，分离实验。对于接触实验，电子探针显微分析揭示了菌丝体矿物聚集体的形成，原子力显微镜成像进一步表明真菌细胞可能摄入矿物颗粒。与对照实验中所观察到的和预期的相比，当真菌和矿物直接混合时，钾的增溶速率表现出对pH的正依赖性，并且如果细胞-岩石接触受到抑制，则与溶液酸度没有相关性。这些结果似乎表明A.烟曲霉通过至少三种可能的途径促进钾的释放，一种是通过可溶性有机配体的络合，另一种是吸引固定的生物聚合物，如分泌物的不溶性组分，第三种是与细胞和矿物颗粒之间的直接物理接触相关的机械力。
A strain of thermophilic fungus Aspergillus fumigatus was cultured with K-bearing minerals to determine if microbe–mineral interactions enhance the release of mineralic potassium. Experiments were carried out in two settings, one with the mineral grains and the fungal cells in direct contact, and the other employing a membrane (pore size 0.22μm) to separate the two. Measurements over a period of 30 days showed that, irrespective of the experimental setup, the concentration of free K in the culture was drastically higher than those in any of the control experiments where no living organism was present. Moreover, the occurrence of mineral–cell physical contact enhanced potassium release by an additional factor of 3 to 4 in comparison to the separation experiments. For contact experiments, Electron Probe Microanalysis revealed the formation of mycelium–mineral aggregates, and Atomic Force Microscopy imaging further indicated the possible ingestion of mineral particles by the fungus cells. Contrasting to what was observed and expected in control experiments, the potassium solubilization rate showed a positive dependence upon pH when fungi and minerals were mixed directly, and exhibited no correlations with solution acidity if cell–rock contact was restrained. These results appear to suggest that A. fumigatus promoted potassium release by means of at least three likely routes, one through the complexation of soluble organic ligands, another appealing to the immobile biopolymers such as the insoluble components of secretion, and the third related to the mechanical forces in association with the direct physical contact between cells and mineral particles.