【摘要】 碳酸钙(CaCO3)沉积不仅在许多地质过程中起重要作用,而且在石刻文物和石质建筑物的修复以及环境治理等方面也有应用。CaCO3沉积过程在自然条件下极为缓慢,在CaCO3-H2O-CO2反应体系中CO2+H2OHCO3-+H+为限速步骤,可以利用生物催化剂来加速这一反应的进行。碳酸酐酶(Carbonic anhydrase,CA)是一种以锌为活性中心的金属酶,可以高效催化上述反应的进行,并在CaCO3沉积中具有显著促进作用。本文采用气体扩散体系,研究温度对典型细菌CA催化CaCO3沉积的速率及晶型晶貌的影响。结果表明,在实验温度(5～55℃)条件下,30℃时细菌CA催化沉积CaCO3的速率最快,而5℃时的沉积速率最慢,而且,温度会影响细菌CA催化形成的CaCO3晶体的大小和形貌。更多还原

【Abstract】 Calcium carbonate(CaCO3) precipitation not only plays an important role in many geological processes,but also has applications in the restoration of stone cultural relics and stone buildings as well as environmental treatments.The CaCO3 precipitation process is very slow under natural conditions.In the reactive system of CaCO3-H2O-CO2,the reaction CO2 + H2 OHCO3- +H+is a rate-limiting step.A biological catalyst could be used to accelerate this reaction.Carbonic anhydrase(CA)is a zinc-containing metalloenzyme that can remarkably catalyze the above reaction.Our previous studies found that microbial CA had significant promoting effect on CaCO3 precipitation.In this paper,the effects of temperature on CaCO3 precipitation rate as well as crystal polymorph and morphology catalyzed by CA from the typical bacteria were investigated through the gaseous diffusion systems.The results showed that under the condition of experimental temperatures(5～55℃),the rate of CaCO3 precipitation catalyzed by bacterial CA was fastest at 30℃,while slowest at 5℃.Moreover,temperature affected the size and morphology of CaCO3 crystals formed by the catalysis of bacterial CA.更多还原