Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada.
Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, M1C 1A4, Canada.
Colloids Surf B Biointerfaces. 2013 Nov 1;111:600-8. doi: 10.1016/j.colsurfb.2013.07.012. Epub 2013 Jul 12.
In the present paper, the impact of freshwater (ARC21 and LS0519) and marine (PCC8806) Synechococcus cyanobacteria on calcium carbonate (CaCO3) precipitation has been examined in respect of the formation rates and morphology of crystals. Acid-base potentiometric titrations were employed to study surface functional groups, while CaCO3 experiments have been carried out in presence and absence of cells at low to near-equilibrium conditions in respect to CaCO3. During these experiments, the pH values have been monitored, Ca and alkalinity were measured and precipitates have been investigated by Raman spectroscopy and Atomic Force and Scanning Electron microscopy. Our results showed that the Synechococcus strains exhibited different surface reactivity with total concentration of surface functional groups of 0.342 and 0.350 mMg(-1) of dry bact. for freshwater strains, and 0.662 mMg(-1) of dry bact. for the marine strain, which are on the same order of magnitude as that reported for bacterial cell surfaces. The marine strain showed the highest CaCO3 formation rate with Ca(2+) removal of 18 mMg(-1) dry bact. compared to 6-7 mMg(-1) dry bact. for freshwater strains. The morphological diversity in crystals has been linked to presence of specific functional groups. The linking cell surface properties to crystal morphologies and precipitation rates propose that bacterial surfaces may modulate CaCO3 formation. Results of this work should allow better understanding of biominiralization in marine and freshwater systems as they define the precipiatation rates in typical range of pH necessary for estimation of CaCO3 formation by cyanobacterial communities.
在本论文中，我们研究了淡水（ARC21 和 LS0519）和海洋（PCC8806）聚球藻蓝细菌对碳酸钙（CaCO3）沉淀的影响，包括晶体的形成速率和形态。我们采用酸碱电位滴定法研究了表面官能团，同时在低至近平衡条件下，在有细胞和无细胞的情况下进行了 CaCO3 实验，以研究 CaCO3。在这些实验中，我们监测了 pH 值，测量了 Ca 和碱度，并通过拉曼光谱、原子力显微镜和扫描电子显微镜研究了沉淀物。我们的结果表明，聚球藻蓝细菌表现出不同的表面反应性，其表面官能团总浓度为 0.342 和 0.350 mMg(-1)干细菌，对于淡水菌株，以及 0.662 mMg(-1)干细菌，对于海洋菌株，这与报道的细菌细胞表面的官能团总浓度相当。海洋菌株的 CaCO3 形成速率最高，Ca(2+)去除量为 18 mMg(-1)干细菌，而淡水菌株的 Ca(2+)去除量为 6-7 mMg(-1)干细菌。晶体形态的多样性与特定官能团的存在有关。将细胞表面特性与晶体形态和沉淀速率联系起来表明，细菌表面可能调节 CaCO3 的形成。这项工作的结果应该可以更好地理解海洋和淡水系统中的生物矿化作用，因为它们定义了在估计蓝藻群落形成 CaCO3 所需的典型 pH 范围内的沉淀速率。
