Algicidal Bacteria: A Sustainable Proposal to Control Microalgae in the Conservation and Restoration of Stone Cultural Heritage

The growth of microalgae poses a significant threat to the preservation of stone heritage, particularly in ornamental fountains and water-related architecture. Traditional chemical cleaning methods, such as quaternary ammonium compounds and chlorine-based solutions, are often ineffective and can be harmful to both the environment and cultural properties. In response, biocleaning, which involves the use of live microorganisms and is part of biorestoration, is gaining prominence in cultural heritage conservation, offering a sustainable alternative to conventional methods. The use of microorganisms antagonistic to microalgae growth has been extensively studied in environmental biotechnology to eliminate harmful algae, though its application in heritage conservation remains limited. This review summarizes current knowledge on bacteria capable of inhibiting microalgae growth, discussing their mechanisms, effectiveness, and potential applications, alongside the environmental and economic benefits and challenges of these methods. By collating and critically assessing available information, this paper aims to serve as a comprehensive resource for conservators, restorers, and researchers interested in innovative and sustainable approaches to combat biodeterioration in stone heritage, thereby fostering the development of effective and environmentally sustainable treatments for such culturally significant properties.