Abstract: The carbon dioxide mineral sequestration is constrained by the leaching rate of Ca2+ and Mg2+ in the raw materials, so the raw materials need to be pretreated. The traditional pretreatment methods (high temperature, acid leaching, etc.) have disadvantages such as high energy consumption and easy pollution, and the use of microbial leaching pretreatment can avoid these disadvantages. A strain well adapted to anorthite was isolated from soil and identified as the fungus Ramichloridium apiculatum. The effects of culture conditions on fungal growth and metabolism were investigated using czapek's medium. Anorthite leaching experiments were carried out under three environments, deionized water, czapek's medium, czapek's medium and fungus, analysis of anorthite changes before and after fungal action by XRD, FTIR, and SEM-EDS. Dialysis was used to further investigate the differences in element release from anorthite under direct/indirect contact modes of the fungus. The results indicate that the optimum growth environment for the fungus is: 4wt% inoculum quantity, glucose as carbon source, NH4Cl as nitrogen source and initial pH of 7.5. The addition of fungus significantly improved the leaching rate of Ca2+ and Mg2+ in anorthite. Compared with deionized water, the leaching rate of Ca2+ and Mg2+ under the action of fungus was 10.04 and 10.11 times that of deionized water. In the direct/indirect leaching experiment, the concentration of Ca2+ and Mg2+ in the direct experiment was always higher than that in the indirect experiment, after 21 days, the leaching rate of Ca2+ and Mg2+ in the direct experiment was 2.94 times and 2.51 times that in the indirect experiment. These results suggest that Ramichloridium apiculatum promotes the leaching of Ca2+ and Mg2+ from anorthite in at least two ways, the first being proton exchange and complexation of fungal metabolites, and the second being physical interaction between the fungus and the mineral.

Key words: bioleaching, growth characteristics, anorthite, Ramichloridium apiculatum, dialysis method

摘要： 二氧化碳矿物封存过程受到Ca2+和Mg2+浸出速率的制约，采用微生物浸矿预处理强化该过程具有低能耗、环境友好、易于大规模工业化实施等优势。从土壤中分离获得一株对钙长石有良好适应能力的菌株，经鉴定为真菌Ramichloridium apiculatum。利用察氏培养基探究培养条件对菌株生长的影响，在最适宜生长条件下进行钙长石浸矿实验，并利用透析法进一步研究真菌直接/间接接触模式下钙长石中元素释放的差异。真菌在接种量4wt%、葡萄糖为碳源、NH4Cl为氮源、初始pH值7.5的条件下生长最好；相比去离子水，真菌使钙长石Ca2+和Mg2+的浸出率分别提高了10.04倍和10.11倍；直接接触实验Ca2+和Mg2+浸出率分别是间接接触实验的2.94倍和2.51倍。真菌通过代谢产物的质子交换、络合作用以及真菌生物物理破坏作用促进钙长石中Ca2+和Mg2+溶出。

关键词: 生物浸出, 生长特性, 钙长石, Ramichloridium apiculatum, 透析法