赖氨酸芽孢杆菌GW-2菌株作用下碳钙镁石的形成

Formation of huntite by Lysinibacillus sp．GW-2 strain

摘要:

摘要:【目的】微生物诱导碳酸盐矿物沉淀机理的研究有可能为CO2的矿物捕获提供科学依据。【方法】本研究在Mg/Ca 为2的B4培养基中对赖氨酸芽孢杆菌GW-2菌株进行了为期50天的培养实验，同时完成了一组无菌对照实验。在实验过程中，对沉淀物重量、培养液的pH值、电导率及其中细菌数量、Ca2+ 和Mg2+浓度等进行了动态监测。利用扫描电子显微镜对矿物形态进行了跟踪观察，利用X-射线衍射仪对矿物成分进行了测定。【结果】(1)在对GW-2菌株进行培养的过程中发现，沉淀物的质量随着培养时间的延长而逐 渐增加，而在无菌对照实验中未收集到沉淀物;(2)各时间段平均沉淀速率与细菌数量之间(r=0.67，P＜0.05)、沉淀物质量与培养液pH值之间(r=0.79，P＜0.05)均具有显著的正相关关系;(3)沉淀物质量与电导率、Ca2+和Mg2+浓度均呈极显著的负相关关系(r分别为0.89、0.93和0.98，P＜0.001);(4)在赖氨酸芽孢杆菌作用下，3种碳酸盐矿物按如下顺序先后形成:非晶态碳酸钙→碳钙镁石→高镁方解石。【结论】(1)赖氨酸芽孢杆菌GW-2菌株具有诱导碳酸盐矿物形成的能力;(2)细菌数量是控制碳酸盐矿物沉淀的直接因素，而较高的pH值是碳酸盐沉淀的必要条件;(3)电导率以及Ca2+和Mg2+浓度的明显降低可以间接地指示碳酸盐矿物沉淀的发生;(4)碳钙镁石可能主要是非晶态碳酸钙经过老化作用而形成，碳钙镁石可能经脱镁作用转变为高镁方解石。

Abstract:

Abstract:［Objective］We studied the formation of carbonate minerals induced by microorganism to explore the possibility of mineral capture．［Methods］Culture experiments of carbonate precipitation were done using B4 medium with 6:1 molar ration of Mg/Ca for 50 days． The same medium without inoculation was used as the control．During the cultivation，bacterial density，precipitate quantities，pH and conductivity of the medium，calciumand magnesium concentration were determined．The morphologies of precipitated carbonates were observed using scanning electron microscopy，and mineral species of carbonate were determined by X-ray diffraction．［Results］ The main results were: (1) In the inoculation process of the Lysinibacillus sp．(GW-2 strain)，we found that precipitate quantities were gradually increased with time，while precipitate was not collected in the aseptic experiments; (2) There were significant positive correlations between bacterial density and average precipitation rate (r=0.67，P＜0.05)，precipitate quantities and pH value (r=0.79，P＜0.05);(3) Precipitate quantities negatively correlated with conductivity，Ca2+ and Mg2+ concentration with correlation coefficients r of 0.89，0.93，0.98 (P＜0.001)，respectively; (4) The three carbonate minerals by Lysinibacillus sp．formed according to following trend: amorphous calcium carbonate→Huntite→High-Mg calcite．［Conclusions］The main conclusions were: (1) Lysinibacillus sp．(GW-2 strain) might induce the formation of carbonate minerals precipitation; (2) The bacterial density directly affected the precipitation of carbonate minerals，whereas pH value indirectly controlled the precipitation of carbonate minerals; (3) Decreased of conductivity，calciumand magnesiumconcentration of the medium could indirectly indicate the occurrence of carbonate precipitate; (4) Huntite might be formed through ageing of amorphous calcium carbonate，whereas high-Mg calcite might be formed through demagnesium of the huntite.