COMPARISON OF BIOCIDES, ALLELOPATHIC SUBSTANCES AND UV-C AS TREATMENTS FOR BIOFILM PROLIFERATION ON HERITAGE MONUMENTS

Author(s): Pfendler S., Borderie F., Alaoui-Sehmer L., Bousta F., Aleya L. and Alaoui- Sossé B.
Paper category: Proceedings
Book title: Proceedings of the Final Conference of RILEM 253-MCI Microorganisms-Cementitious Materials Interactions Volume II
Editor(s): Alexandra Bertron and Henk Jonkers
ISBN: 978-2-35158-207-7 (Set)
ISBN: 978-2-35158-210-7 (Volume 2)
e-ISBN: 978-2-35158-206-0
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 575-576
Total Pages: 308
Language : English

Abstract: Pfendler et al. [1] identified, for the first time, microorganisms proliferating in one Swiss and in four French show caves using three different primers. The results showed that both photosynthetic and non-photosynthetic bacteria were the dominant taxa present in biofilms. UV-C and biocide treatments are frequently used to treat historical monuments contaminated biofilms [2,3,4,5]. In this work, biofilms were studied using next generation sequencing which permits to record wide taxa diversity in biofilm such bacteria, fungi, cyanobacteria, algae, diatoms and mosses [1]. Thus, the authors compare for the first time the efficacy of biocides and UV-C treatments against biofilm microorganisms proliferating in the Vicherey church (Vicherey, Vosges Department, France). To identify the most environmentally friendly and also efficient method, an allelopathic treatment was also tested. Colorimetric and physiological measurements of treated biofilms were thus monitored for 6 months. Fungi growing on necrotic matter from treated biofilms were sampled and sequenced. With biocides, results showed incomplete eradication of biofilms, even after two treatments. Biofilm color loss was delayed in comparison to UV-C treatment, which appeared more efficient after just one treatment. Moreover, quantum yield (F’v/F’m) decreased immediately after UV-C treatment, indicating inhibition of algae and cyanobacteria photosynthesis. However, two species of fungi colonized the cyanobacteria biofilms treated with UV-C. Cultures obtained after sampling led to isolation of two different fungi species belonging to the Ascomycota phylum; Penicillium and Engyodontium which have been identified using light microscopic observation and Sanger sequencing technic [6]. Otherwise, allelopathic treatment was not efficient on biofilm and showed no deleterious effect on photochemical efficiency [6]. The present findings demonstrate that the UV-C method, coupled with a cleaning phase for necrotic organic matter, may be considered environmentally friendly and the best alternative to chemicals.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00