Biocatalytic capture of CO2 with carbonic anhydrase and its transformation to solid carbonate
Biocatalytic capture of CO2 with carbonic anhydrase and its transformation to solid carbonate
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DOI：
10.1016/j.molcatb.2009.04.018
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发表时间：
2009-10-01
影响因子：
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通讯作者：
Pierre, Alain C.
中科院分区：
文献类型：
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作者：
Favre, Nathalie;Christ, M. Lorraine;Pierre, Alain C.
众所周知，大气CO2是地球上“绿色房屋”效应的主要贡献者，因此它值得作为任何环境污染物来对待。本论文的重点是它的生物催化捕获的酸酐酶碳酶形成HCO 3-阴离子，然后捕获固体碳酸钙在碱性条件下，在“一锅”的过程。在5 ℃和20 ℃下比较了有和没有酶的CaCO 3形成的动力学，以及形成的固体的结晶性质。根据温度和所用缓冲液的初始pH值，观察到两种不同的固相：亚稳球霰石和稳定菱面体方解石。当使用初始pH为10.5的缓冲储备溶液时，不使用任何酶，球霰石的形成得到增强。可能的机制来解释这些意见进行了讨论。在5 ° C下，固体CaCO 3的初始沉淀速率通过添加酶而增加，增加倍数>10。然而，该初始速率也被发现依赖于酶的浓度和缓冲容量。取决于这两个参数，在第一步骤中增加HCO 3-的形成速率可如此快速地降低反应介质pH，以致于在第二步骤中固体碳酸盐的沉淀可被高度阻碍。因此，固体CaCO 3的总形成速率实际上可能降低，例如当酶的质量增加时。(C)2009 Elsevier B. V.保留所有权利。
Atmospheric CO2 is well known to be a major contributor to the "green house" effect on earth and as such it deserves to be treated as any environmental pollutant. The present paper focused on its biocatalytic capture by an anhydrase carbonic enzyme to form HCO3- anions, followed by trapping as solid CaCO3 in basic conditions, in a "one pot" process. The kinetics of CaCO3 formation with and without enzyme were compared at 5 and 20 degrees C, as well as the crystalline nature of the solid formed. Depending on the temperature and the initial pH of the buffer used, two different solid phases were observed: metastable vaterite and stable rhombohedra calcite. The formation of vaterite was enhanced when a buffer stock solution at an initial pH of 10.5, without any enzyme, was used. The possible mechanisms to explain these observations are discussed. At 5 degrees C, the initial precipitation rate of solid CaCO3 increased by the addition of the enzyme, by a multiplication factor >10. However, this initial rate was also found to depend on the concentration of enzyme and the buffer capacity. Depending on these two parameters, an increasing formation rate of HCO3- in a first step, may lower the reaction medium pH so quickly, that the precipitation of solid carbonate in a second step may be highly hindered. As a consequence, the overall formation rate of solid CaCO3 may actually decrease, for instance when the mass of enzyme is increased. (C) 2009 Elsevier B.V. All rights reserved.