Consolidation of stone sculptures using the biomineralization method

Author: Barbara Dragan, acad. restorer
Mentors: Blaž Šeme, PhD, Assistant Professor; Sabina Kramar, PhD, Assistant Professor

Department of Conservation and Restoration of Works of Art, Academy of Fine Arts and Design, University of Ljubljana (Slovenia)
Study programme: Second-Cycle Master's Programme of Study in Conservation and Restoration of Works of Art
Specialization: Paintings and Polychrome Plastic (1st year of study)


DRAGAN BarbaraThe biomineralization method uses carbonatogenic bacteria to form biocalcite for the purpose of consolidating cultural heritage objects made of carbonate stones. The paper sums up my bachelors’ thesis, where I examined the effect of the consolidation of objects made of carbonate stones by the method of biomineralization. The very definition of the methods’ concept as well as the short process of the operation is presented. For the experiment, the commercial product Calcite Bioconcept, which contains two components: lyophilised bacteria Bacillus Cereus named Biocal and a nutrient called Nutrical, was used. The paper encompasses the presentation and the analysis of the results of colorimetry, drilling resistance measurements (DRMS) and the ultrasound velocity measurements (USV) before and after the consolidation. Measurements were carried out on laboratory samples of limestone and marble. Moreover, the description of the process of consolidation of a damaged marble relief, which is kept in Museum & Galleries of Ljubljana, is also included. Consolidation of the object proved to be successful, however, some improvements should be made.

Short biography

BARBARA DRAGAN was born in 1993. She is a student of MA programme of the Conservation and Restoration of Works of Art at the Academy of Fine Arts and Design of University of Ljubljana. Even though she was mainly focused on anorganic materials during her studies she is now specializing in Conservation and Restoration of easel paintings and polychrome wooden objects. In 2016 she defended bachelors’ thesis “Consolidation of Stone Sculptures using the Biomineralization Method” at the Academy.