| Popis: |
On the surface of the mural paintings of the Takamatsuzuka and Kitora Tumuli, there exist undesirable biofilms made of microbial cells of fungi, yeast, bacteria and their extracellular substances. To remove the biofilms, cell lytic enzymes were selected and examined for the effects on various restorative materials and mineral pigments that are identical with the mural paintings of the Takamatsuzuka and Kitora Tumuli. Among the commercially produced enzymes, Achromopeptidase, Lysozyme, β-1,3-glucanase and chitinase were selected. To evaluate the effects of these enzymes on the restorative materials, degradation activity was examined using nine substrates: hydroxypropyl cellulose, methyl cellulose, purified funori, carboxymethyl cellulose, filter paper, starch, xylan, casein and palmitic acid. As a result, Achromopeptidase showed no degradation activity to tested restorative materials other than casein. Thus, the use of Achromopeptidase is inappropriate when using restorative materials based on proteins such as glue. Lysozyme, β-1,3-glucanase and chitinase showed no degradation activity to any of the restorative materials. Regarding the influence on mineral pigments, color difference became large in the gold foil and silver foil samples in all cases. It is considered that this is because the enzyme solution dried and solidified on the surface of the metal foil, and the solute component of the enzyme precipitated. Therefore, in actual cleaning work, it is considered that change in color hardly occurs because enzyme solution is suctioned before drying. The results suggest that the enzymes tested in this study can be applied for removing microbial contamination on the mural paintings of the Takamatsuzuka and Kitora Tumuli. |
