Onsite advanced biocleaning system on ancient wall paintings using new agar-gauze bacteria gel

Aims: In this study the results of the use of a new agar-gauze biogel system activated by viable bacterial cells applied on altered wall-paintings are reported. Methods and Results: Biocleaning using agar biogel and agar-gauze biogel systems was performed onsite by direct application onto altered wall-painting artwork surfaces (25-1,000 cm2). The treatments were performed for the restoration of two original Italian sites: i) at the Vatican Museums, Cristo che salva Pietro dalle acque - La Navicella wall-painting by Giovanni Lanfranco (1627-1628) and ii) at Pisa Cathedral Cupola, Incarnato wall-painting by Orazio Riminaldi (1593-1630) and his brother (Girolamo Riminaldi). The novelty of this study is the use of Pseudomonas stutzeri A29 viable cells using an advanced agar-gauze biogel system and that the bioapplications required short contact-times of between 3-12 hours. The ancient artworks were altered by lipid and protein residues from past restoration as confirmed by the Py-GC/MS and FTIR data. Assessment was made on the effectiveness of the biological treatment and general considerations were discussed. Conclusions: The short contact-time of the bioapplications using advanced agar-gauze gel activated with P. stutzeri viable cells makes this biotechnology promising as an alternative method to the traditional onsite cleaning techniques currently in use for altered ancient wall-paintings. Significance and Impact of the Study. In this study, we report the biocleaning of altered materials located in vertical and vaulted areas using agar-gauze biogel and short application times for the first time. These findings are of great significance for future restoration activities, being crucial for determining best preservation strategies in this field.