| In recent years, microbial technology as a new research method has begun to be applied in the protection of cultural relics, and has been paid more and more attention by domestic and foreign researchers. The mineralization induced by bacteria is an effective method to repair, protection of stone relics. In order to explore the biological mineralization of calcium carbonate for reinforcement of stone relics surface structure. This experiment from Huanglong travertine alpine sedimentary water were isolated from two strains of with high carbonic anhydrase(CA) activity of eosinophils cold type strains. To study the effect of strain on calcium carbonate deposition process by changing the deposition was measured by p H value and conductivity, and crystalline morphology were analyzed by X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR) instrument and scanning electron microscopy(SEM) on the formation of calcium carbonate crystals; Methods of SEM and XRD were adopted to characterize the form and morphology of calcium carbonate crystal under short period and long period. To test the repair effect of the surface mineral deposition induced by the 2 psychrotrophic strains with high yield of carbonic anhydrase(CA) activity, we measured the changes of p H value of solution, surface mineral deposition, surface water absorption, surface air permeability, surface acid resistance, acid resistance, stain resistance, corrosion resistance, Alkali resistance of marble during the mineralization process. The main results obtained are as follows:(1) 2 psychrotrophic strains were isolated from the water of Huanglong with high yield of carbonic anhydrase(CA) activity. Numbers were SWU15-10 and SWU18-10. The results showed that strains 16 S r DNA was identified as Pseudomonas sp.. The optimal combination of the strains SWU15-33 was temperature 15 ?, incubation time 12 h, p H 6.0, and inoculation 2.0 m L. As forstrains SWU18-10, the optimal combination was temperature 15 ?, incubation time 24 h, p H 6.5, and inoculation 2.0 m L.(2) Under different conditions, the tested strains can promote the deposition of calcium carbonate, and the crystals are calcite, but the morphology is different.Comprehensive impact of different initial p H value and different processing temperature of calcium carbonate crystal, especially at the initial p H 8, the influence of the deposition of calcium carbonate at low temperature is the most significant.(3) Different methods of long-term experiment and short-term test of viable bacteria and destroy living strains can in the marble surface successfully induced deposition of calcite type calcium carbonate, but the deposition and crystal morphology is not the same, long-term experiment can achieve better deposition and reinforcement effect.(4) In the marble specimen, the dense calcium carbonate was formed, which is the calcium carbonate and the crystal morphology is controlled by the bacteria.The test piece of the formation of the mineralized layer is more beneficial to the corrosion resistance of the water absorption, air permeability and acid resistance.In summary, the results of the study show that the 2 tested psychrotrophic strains with high yield of carbonic anhydrase(CA) activity can in some extent modulate calcium carbonate deposition rate and the crystal structure and morphology. Using its ability of calcium carbonate mineralization repairing of the surface of stone cultural relics. The results not only enrich the microbial groups which can remediation of stone relics, also provide a theoretical basis to explore the low temperature of Huanglong travertine biological deposition mechanism. What is more, the results could provided certain theory and practical evidence of reinforce application on marble surface with bacterium. And it is also has a certain significance to reveal the carbonate mineralization mechanism induced by the carbonic anhydrase. |
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