An integrated approach for assessing the bioreceptivity of glazed tiles to phototrophic microorganisms

M L Coutinho,A Z Miller,M A Rogerio-Candelera,J Mirão,L Cerqueira Alves,J P Veiga,H Águas,S Pereira,A Lyubchyk,M F Macedo

doi:10.1080/08927014.2015.1135242

M L Coutinho, A Z Miller + Show 8 more

Open Access

https://doi.org/10.1080/08927014.2015.1135242

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Abstract

A laboratory-based methodology was designed to assess the bioreceptivity of glazed tiles. The experimental set-up consisted of multiple steps: manufacturing of pristine and artificially aged glazed tiles, enrichment of phototrophic microorganisms, inoculation of phototrophs on glazed tiles, incubation under optimal conditions and quantification of biomass. In addition, tile intrinsic properties were assessed to determine which material properties contributed to tile bioreceptivity. Biofilm growth and biomass were appraised by digital image analysis, colorimetry and chlorophyll a analysis. SEM, micro-Raman and micro-particle induced X-ray emission analyses were carried out to investigate the biodeteriorating potential of phototrophic microorganisms on the glazed tiles. This practical and multidisciplinary approach showed that the accelerated colonization conditions allowed different types of tile bioreceptivity to be distinguished and to be related to precise characteristics of the material. Aged tiles showed higher bioreceptivity than pristine tiles due to their higher capillarity and permeability. Moreover, biophysical deterioration caused by chasmoendolithic growth was observed on colonized tile surfaces.

Highlights

Microbial communities colonizing historical glazed tiles have recently been assessed by several authors, providing a first insight on the diversity of bacteria, cyanobacteria, microalgae and fungi dwelling on ceramic tiles (Oliveira et al 2001; Pedi et al 2009; Giacomucci et al 2011; Coutinho et al 2013; Silva et al 2014)
Several studies have been devoted to stone bioreceptivity (e.g. Miller et al 2012; Guillitte & Dreesen 1995; Tiano et al 1995) and only a few have been focused on modern ceramic materials, such as roofing tiles and bricks (Gazulla et al 2011; Gladis & Schumann, 2011; Portillo et al 2011; D’Orazio et al 2014)
The experimental set-up of this work followed five specific steps: i) manufacture of majolica glazed tile models based on the composition of historical glazed wall tiles from Pena National Palace (Sintra, Portugal); ii) artificial aging of the manufactured model tiles to simulate the natural aging process; iii) chemical and physical characterization of the tiles reproduced in this work; iv) inoculation and incubation of the majolica glazed tile models with a selected mixture of phototrophic microorganisms, and v) assessment of microbial growth and biodeteriorating potential of the inoculated microorganisms on the majolica glazed tile models

Summary

Introduction

Microbial communities colonizing historical glazed tiles have recently been assessed by several authors, providing a first insight on the diversity of bacteria, cyanobacteria, microalgae and fungi dwelling on ceramic tiles (Oliveira et al 2001; Pedi et al 2009; Giacomucci et al 2011; Coutinho et al 2013; Silva et al 2014). Several studies have been devoted to stone bioreceptivity (e.g. Miller et al 2012; Guillitte & Dreesen 1995; Tiano et al 1995) and only a few have been focused on modern ceramic materials, such as roofing tiles and bricks (Gazulla et al 2011; Gladis & Schumann, 2011; Portillo et al 2011; D’Orazio et al 2014). Most of these studies relied on the artificial inoculation of organisms on a substrate under controlled environmental conditions The aim of this study was to develop an integrated laboratory-based methodology to assess the primary and secondary bioreceptivity of majolica glazed tiles to phototrophic microorganisms and analyze their 102 biodeteriorating potential

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