Abstract Microbial carbonic anhydrase promotes carbonate deposition, which is important in the formation and evolution of global carbon cycle and geological processes. A kind of bacteria producing extracellular carbonic anhydrase was selected to study the effects of temperature, pH value and Ca2+ concentration on bacterial growth, carbonic anhydrase activity and calcification rate in this paper. The results showed that the activity of carbonic anhydrase at 30 °C was the highest, which was beneficial to the calcification reaction, calcification rate of CaCO3 was the fastest in alkaline environment with the initial pH value of 9.0. When the Ca2+ concentration was 60 mM, compared with other Ca2+ concentration, CA bacteria could grow and reproduce best, and the activity of bacteria was the highest, too low Ca2+ concentration would affect the generation of CaCO3, while too high Ca2+ concentration would seriously affect the growth of bacteria and reduce the calcification rate. Finally, the mechanism of CaCO3 precipitation induced by microbial carbonic anhydrase was studied. Carbonic anhydrase can accelerate the hydration of CO2 into HCO3−, and react with OH− and Ca2+ to form CaCO3 precipitation in alkaline environment and in the presence of calcium source.

中文翻译：

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微生物碳酸酐酶诱导CaCO3沉淀的影响因素及形成机制

摘要 微生物碳酸酐酶促进碳酸盐沉积，对全球碳循环和地质过程的形成和演化具有重要意义。本文选择一种胞外碳酸酐酶产生菌，研究温度、pH值和Ca2+浓度对细菌生长、碳酸酐酶活性和钙化率的影响。结果表明，30℃时碳酸酐酶活性最高，有利于钙化反应，CaCO3在碱性环境中钙化速度最快，初始pH值为9.0。当Ca2+浓度为60 mM时，与其他Ca2+浓度相比，CA细菌的生长繁殖能力最好，细菌的活性最高，Ca2+浓度过低会影响CaCO3的生成，Ca2+浓度过高会严重影响细菌的生长，降低钙化率。最后，研究了微生物碳酸酐酶诱导CaCO3沉淀的机理。碳酸酐酶可加速CO2水合为HCO3−，在碱性环境和钙源存在下与OH−和Ca2+反应生成CaCO3沉淀。