Institute of Resource Biology and Biotechnology, College of Life Science & Technology, Huazhong University of Science & Technology, Wuhan 430074, PR China.
Colloids Surf B Biointerfaces. 2013 Feb 1;102:281-7. doi: 10.1016/j.colsurfb.2012.08.042. Epub 2012 Sep 3.
The dynamics of calcium carbonate (CaCO(3)) precipitation induced by microbial intracellular or extracellular carbonic anhydrase (CA) at initial pH 6.0, 6.5, 7.0 and 8.0 were investigated through the gaseous diffusion method. The results indicated that both the intracellular and extracellular CA could promote CaCO(3) precipitation. The Ca(2+) ions in the enzymatic systems at initial pH 8.0 were completely deposited at 48 h, which were respectively 21 h, 15 h and 14 h earlier compared with that at initial pH 6.0, pH 6.5 and pH 7.0, indicating that higher pH favored CaCO(3) precipitation in the experimental pH range, and was beneficial to the catalytic action of microbial CA on CaCO(3) precipitation. In addition, XRD analysis indicated that the CaCO(3) precipitates were mainly calcite crystals in the presence of microbial CA. With increasing deposition time, the crystals gradually changed from prism shape to pyramid-like or irregular polyhedral shape based on FESEM analysis.
采用气态扩散法研究了初始 pH 值为 6.0、6.5、7.0 和 8.0 时微生物细胞内或细胞外碳酸酐酶（CA）诱导碳酸钙（CaCO（3））沉淀的动力学。结果表明，细胞内和细胞外 CA 均可促进 CaCO（3）沉淀。在初始 pH 值为 8.0 的酶体系中，48 h 时 Ca（2+）离子完全沉淀，比初始 pH 值为 6.0、6.5 和 7.0 时分别提前 21 h、15 h 和 14 h，表明在实验 pH 范围内，较高的 pH 值有利于 CaCO（3）沉淀，有利于微生物 CA 对 CaCO（3）沉淀的催化作用。此外，XRD 分析表明，在微生物 CA 的存在下，CaCO（3）沉淀物主要为方解石晶体。基于 FESEM 分析，随着沉积时间的增加，晶体逐渐从棱柱形变为金字塔形或不规则多面体形。
