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Abstract: Fumigants, including methyl bromide and ethylene oxide, are generally used for the preservation of the Korean cultural heritage, especially paper products like letters and books. However, the use of fumigants is banned because of their harmful effects on humans and the environment. Gamma irradiation is being considered as an alternative for the sterilization of insects and fungi in organic products. Therefore, the purpose of this study was to investigate the sterilization effects of radiation and its effect on the mechanical properties of the Korean traditional paper—Hanji. Treatment doses of 9kGy and 8kGy of gamma irradiation inactivated 5 log units of Aspergillus niger and Bacillus cereus spores inoculated on Hanji, respectively. The gamma irradiations up to an absorbed dose of 50kGy resulted in no significant changes in the tensile strength, bursting strength, and appearance of Hanji. These results confirmed that radiation treatment disinfects the Korean traditional paper efficiently without changing its properties and that this treatment could be used to prevent the damage of Korean ancient archives by molds and fungi. [Copyright &y& Elsevier]

We investigated the wood-damaging characteristics of microorganisms by conducting decay tests on the surface of woodblocks made from the wood of Prunus sargentii , with the aim of identifying ways to preserve the woodblocks. The microorganisms were classified into 29 types of fungi and 6 types of bacteria. Among them 11 types of fungi showed high wood-degrading enzyme activity, and hence classified under risk levels 2–3. We also found that the anti-mold effect of P. sargentii was low, based on the finding that surface contaminants such as Eupenicillium rubidurum and Penicillium oxalicum grew on the P. sargentii specimen. In addition, these strains were grew on the surface of a lacquered P. sargentii specimen, and the anti-mold effect of the lacquer did not seem to correlate with the number of lacquer applications. The P. sargentii specimen was found to have a higher weight loss rate than a Pinus densiflora specimen, which indicated that the preservative effect of P. sargentii against Coprinellus radians was low. However, the weight loss rate of the lacquered P. sargentii specimen was low, and mycelium was not observed in the wood tissue. In conclusion, we believe that lacquer exerts a preservative effect on P. sargentii specimens. [ABSTRACT FROM AUTHOR]

• Reconstruction experiments of biodeterioration on materials are crucial in testing biocides. • Interference of biocides with materials and pigments cannot be neglected. • Stone porosity strongly affects the biocidal efficiency. • Eco-friendly emulsifiers can act as tertiary bioreceptivity agents. Hypogeal environments due to their limited air circulation, low constant temperatures and high humidity could be threatened by microbial spreading. In cultural heritage preservation, natural bioactive molecules have been proposed as a possible alternative to traditional biocides. Although several papers report the in vitro effect of green biocides, scant information is available about their efficacy in direct application and interaction with historical materials. Then, we investigated five green biocidal formulations never applied before to control the biodeterioration of subterranean mural painting raising from Italian and South Korean traditions. We tested three emulsified essential oil-based (oregano and clove bud) water suspensions, and usnic acid-based water and 2-propanol/dimethyl sulfoxide (7:3) solutions for establishing: (i) possible interference with the reconstructed ancient wall paintings materials (colour and water adsorption changes), (ii) efficacy on recurrent biodeteriogens, trough optical/electronic microscopy, bioluminometric and culture-based methods. Results evidenced the different impact of such biocides on wall paintings' materials and pigments (e.g., higher on red and black Etruscan tiles). They also highlight the importance of reconstruction experiments for customizing treatments, avoiding interference with historical materials (e.g., changes in colour) and biodeteriogens' spreading. The active principles concentration and stone porosity strongly affect the biocidal efficacy, but the solvent and emulsifier used also had a relevant role. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, an eco-friendly biocide was prepared from natural medicinal ingredients that are traditionally used to preserve and maintain outdoor stone monuments in South Korea, and its effectiveness was verified through laboratory testing and on-site application. Eugenol, which was isolated and identified from volatile clove extracts, was mixed together with eco-friendly emulsifiers from the Tween and Span series at different ratios to prepare an optimized biocide. Strong antifungal activities were confirmed when the biocide was tested against 19 types of molds that were isolated and identified from the biofilms of two World Heritage Sites: the Royal Tombs of the Joseon Dynasty in South Korea and the Vat Phou temple in Laos. When applied on-site, the lichen became decolorized and discolored, and was ultimately eliminated from the surface as the mycelium in its epithelial layer disintegrated. Furthermore, an average of 80% reduction in microorganisms was observed from the applied surface based on ATP measurements before and after biocide treatment. The developed biocide shows high prospects for commercial use as part of an eco-friendly technology applicable to outdoor stone monuments. [ABSTRACT FROM AUTHOR]

Gamma irradiation can destroy fungi and insects involved in the bio-deterioration of organic cultural heritages. However, this irradiation procedure can alter optical and structural properties of historical pigments used in wooden cultural heritage paintings. The crystal structure and color centers of these paintings must be maintained after application of the irradiation procedure. In this study, we investigated the effects of gamma irradiation on Korean traditional multicolored paintwork (Dancheong) for the preservation of wooden cultural heritages. The main pigments in Korean traditional wooden cultural heritages, Sukganju (Hematite; Fe 2 O 3 ), Jangdan (Minium; Pb 3 O 4 ), Whangyun (Crocoite; PbCrO 4 ), and Jidang (Rutile; TiO 2 ), were irradiated by gamma radiation at doses of 1, 5, and 20 kGy. After irradiation, changes in Commision Internationale d’Eclairage (CIE) color values ( L *, a *, b *) were measured using the color difference meter, and their structural changes were analyzed using X-ray diffraction (XRD) analysis. The slightly change in less than 1 dE * unit by gamma irradiation was observed, and structural changes in the Dancheong were stable after exposure to 20 kGy gamma irradiation. In addition, gamma irradiation could be applied to painted wooden cultural properties from the Korean Temple. Based on the color values, gamma irradiation of 20 kGy did not affect the Dancheong and stability was maintained for five months. In addition, the fungicidal and insecticidal effect by less than 5 kGy gamma irradiation was conformed. Therefore, the optical and structural properties of Dancheong were maintained after gamma irradiation, which suggested that gamma irradiation can be used for the preservation of wooden cultural heritages painted with Dancheong. [ABSTRACT FROM AUTHOR]

Abstract: The annals of the Choson dynasty, a group of archives including 2077 volumes dated from 1392 till 1863 were declared National Treasury by the Korean government in 1973 and were later registered as Memory of the World by Unesco in October 1997. Some of these historical papers, coated with a wax substance, are called Korean wax papers. They present nowadays various patterns of degradation. As little is known about the waxes used and the techniques employed to wax the papers, it appeared necessary to identify the substances used and to assess their degree and pathways of alteration to further define adapted conservation treatment and preservation conditions. We focused in this paper on four microsamples taken from different waxed Choson manuscripts dated from the 15th and 16th centuries. A modern Korean beeswax sample was also analyzed as reference. A two-step analytical methodology based on infrared spectroscopy, HT-GC and HT-GC/MS analysis was developed. These investigations led to the identification of beeswax in all the samples. In a single sample, paraffin was also determined, indicating a step of restoration, possibly during the 19th century or afterwards. All the samples revealed an altered pattern of beeswax that is reported here for the first time. Particularly, the presence of hydroxyesters in high amount and the formation of n-aldehydes are new and interesting results that may be explained by the use of previous oxidative treatments. Depletion of the shortest chain n-alkanes and monoesters was also observed. The different alteration pathways of beeswax in Korean wax papers are fully discussed in this paper. [Copyright &y& Elsevier]