低温环境下两种氨基酸对碳酸钙矿化影响的研究

A Simulation Study on the Effect of Bacterial Extracellular Feature Amino Acids on Calcium Carbonate Mineralization Under Low Temperature

黄龙景区高寒冷水型钙华沉积地貌环境中生存着大量的嗜冷微生物。为了探究这些微生物在低温及高浓度Ca^(2+)和HCO_3^-水环境中的代谢产物对钙华沉积的影响,本实验选取黄龙嗜冷细菌的两种特征代谢产物L-苯丙氨酸和L-半胱氨酸,通过模拟低温、含较高浓度的Ca^(2+)和HCO_3^-的实验环境,并利用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)等分析方法,来探讨氨基酸对矿化体系中碳酸钙沉积速率及其晶型和形貌的影响。实验结果表明:在特定模拟环境条件下,(1)L-苯丙氨酸和L-半胱氨酸均能促进碳酸钙的沉积。L-苯丙氨酸对晶型影响不大,产物均为方解石型碳酸钙,但是L-苯丙氨酸能抑制方解石晶面棱边的生长,使得晶体出现多面不规则的立方体形态;(2)L-半胱氨酸除诱导并促进方解石型碳酸钙的合成外还可以诱导文石型碳酸钙的合成。该结果可为黄龙地区钙华的生物成因研究提供一定的基础数据。

A large number of psychrophilic microorganisms colonize in the cold water of Huanglong scenic, a typical travertine landscape in plateau with low temperature all the year. To explore the effect of biological metabolites of these organisms on the process of travertine deposition in the low temperature environment with high concentration of Ca^(2+) and HCO_3^-, two typical extracellular amino acids products, i. e., L-phenylalanine and L-cysteine, were chosen as the research objects. The experimental environment of low temperature and high concentration of Ca^(2+) and HCO_3^- was simulated in the lab. And the methods of X-ray diffraction(XRD), infrared absorption spectroscopy(FT-IR) and scanning electron microscopy(SEM) were used to measure the deposition rate, the shape and morphology of the crystal of calcium carbonate. The experimental results show as the follows:(1) both phenylalanine and cysteine promote the deposition of calcium carbonat in the specific simulation environment. The effect of phenylalanine on the crystal shape is not very obvious, and the crystal products are all calcite. But phenylalanine inhibits the growth of calcite crystal edge and makes the crystal appear shapes of multifaceted, irregular cube.(2) In addition to inducing and promoting the synthesis of calcite type calcium carbonate, L-cysteine also induces the forming of aragonite. The results can provide theoretical data for exploring the travertine biological forming in Huanglong valley.