硅酸盐解钾菌对含钾矿物的选择性风化机理

Selective Bio-weathering Potassium-bearing Mineral by Silicate Bacteria

从棉花根际土壤中筛选、分离、纯化了硅酸盐解钾菌,进行了硅酸盐解钾菌与7种含钾矿物在厌氧密闭系统中的生物风化解钾试验,探讨了硅酸盐解钾菌对不同含钾矿物生物风化作用的规律。试验结果表明,生物风化反应释放出K+最多的前3个组合是白云母和QY17、黑云母和QY19、白云母和QY19,反应释放出K+的量分别为1 235.76、1 010.71、916.61μg/g。生物风化反应固定K+最多的4个组合是黑云母和QY4、蒙脱石和QY3、黑云母和QY10、高岭石和QY17,反应中含K矿石固定K+的量分别为78.35、39.92、32.71、22.56μg/g。形成差异的原因可能是硅酸盐解钾菌(包括其次生代谢物)与含钾矿物的晶体结构之间的双向选择过程。硅酸盐解钾菌浓度越大,硅酸盐解钾菌类群对矿物生物风化作用有选择性倾向越明显。造成硅酸盐解钾菌的解钾数量、速率的差异的原因是界面交换过程的不同,机理是硅酸盐解钾菌(次生代谢物)与含钾矿物之间空间构效关系(CQSAR)。风化作用是硅酸盐细菌剥蚀作用、机械破碎、次生有机酸解钾过程交替循环所产生的。腐殖酸的加入促进了硅酸盐解钾菌解钾的过程,延长了解钾时间,同时向硅酸盐解钾菌提供C、N养分。

The silicate bacteria were isolated and purified from cotton’s rhizosphere. The biological weathering experiments by silicate bacterium with muscovite,kaolinite,biotite,potassium feldspar,smectite,illite,vermiculite were conducted in anaerobic airtight system. The laws of the silicate bacteria with different potassium mineral biological weathering were investigated. The results showed that in biological weathering reactions,the first three combinations of releasing K＋ were QY17 ＋ muscovite, muscovite ＋ QY19,biotite ＋ QY19 with the releasing amounts of K＋ of 1 235.76 μg/g,1 010.71 μg/g, and 916.61 μg/g, respectively. The first four combinations of fixed K＋ were biotite ＋ QY4,smectite ＋ QY3,biotite ＋ QY10,kaolinite＋QY17. The fixed amounts of K＋ were 78.35 μg/g,39.92 μg/g,32.71 μg/g,22.56 μg/g,respectively. The reason maybe be double-choice process between silicate bacteria （and its secondary metabolites） and potassium mineral crystal structure. The cause of differences of releasing potassium ions in quantity and rate was the different interface exchange process between the silicate bacteria and potassium mineral. The mechanism was quantitative structure-activity relationship （QSAR） between the silicate bacteria （secondary metabolites） and potassium mineral. Weathering denudation is a cycle process of silicate bacteria biological weathering,mechanical crushing,and secondary organic acid depolymerization. Humic acid had the capacity of promoting release of K＋ and extending the interaction time in the process of biological weathering. C,N nutrient elements were provided for silicate bacteria at the same time.