(1. 九江學院 化學與環(huán)境工程學院，九江 332005；
2. 北京科技大學 土木與環(huán)境工程學院，北京 100083)
摘 要: 微生物對鋁硅酸鹽礦物的風化分解包含直接作用與間接作用兩種方式。采用微孔濾膜將細菌與礦物隔離，在細菌-礦物直接接觸與間接接觸兩種模式下，研究環(huán)狀芽孢桿菌對鋁土礦風化分解行為的影響。結果表明：在細菌生長的0~216 h 內，細菌及代謝產物能通過直接和間接作用共同促進鋁土礦的分解，但直接作用的強度明顯大于間接作用的；Al的溶出主要受直接作用的影響，而鋁土礦中K、Fe和Si 的溶出率主要受間接作用的影響；細菌代謝產物對溶出的Al具有明顯的絮凝抑制作用，對Si 具有良好的分散性能；細菌對鋁土礦中不同晶體結構的硅酸鹽礦物具有“選擇性”的分解作用，具層狀結構的高嶺石、伊利石、綠泥石較架狀結構的石英更易被細菌風化分解；在直接作用模式下，細菌在生長過程中會產生大量的胞外多聚物，細菌和礦粉之間會形成菌體-礦物聚集體，促進鋁土礦的分解。分析認為，細菌對鋁土礦的分解過程包括機械破壞、代謝產物溶蝕、絡合作用及這3種作用的協(xié)同效應。
關鍵字: 鋁土礦；環(huán)狀芽孢桿菌；風化分解；直接作用；間接作用
（1. School of Chemistry and Environmental Engineering, Jiujiang University, Jiujiang 332005, China;
2. School of Civil and Environmental Engineering, University of Science and Technology Beijing, ）
Abstract:The microbial decomposition mechanisms of bauxite include direct and indirect mechanism, while the contribution of each mechanism to the mineral weathering is still in controversy. The impact of Bacillus circulans on decomposition of bauxite was studied under the conditions of microbe-mineral direct contact and indirect contact. The microfiltration membrane was used to segregate mineral powder from bacteria. The results show that Bacillus circulans and its metabolites can clearly promote the degradation of bauxite through either mechanisms during incubation in 0- 216 h, and the effect of direct mechanism on the mineral degradation is more efficient than that of indirect one. The Al dissolution from bauxite is mainly determined by the direct mechanism, and K, Fe, Si are considered to be released by indirect mechanism. The bacterial metabolites can flocculate and inhibit Al in supernatants, but have good dispersibility on Si. The Bacillus circulans can selectively degrade different minerals due to the difference in mineral crystal structure. Kaolinite, illite and chlorite with layer structure are more easily decomposed than quartz with framework structure by bacteria. The Bacillus circulans can produce extracellular polymeric substances during incubation, and form the mycelium-mineral aggregate between bacteria and mineral powder. It is concluded that the Bacillus circulans can decompose bauxite at the mechanical breakage of the mycelium growth, the corrosion and complexation of metabolites and their synergetic operation.
Key words: bauxite; Bacillus circulans; weathering decomposition; direct mechanism; indirect mechanism
