Authors: Willem De Muynck Kim Verbeken Nele De Belie Willy Verstraete
Publish Date: 2012/03/18
Volume: 97, Issue: 3, Pages: 1335-1347
Abstract
So far most studies on microbiologically induced carbonate precipitation for limestone conservation have been performed at temperatures optimal for the activity of the calcinogenic bacteria ie 20–28 °C Successful application in practice however requires adequate performance in a wide range of environmental conditions Therefore the aim of this study was to select microorganisms that are most suited for biodeposition at temperatures relevant for practice In a first step ureolytic microorganisms were screened for their growth and ureolytic activity at different temperatures 10 20 28 and 37 °C Large differences in calcinogenic activity could be observed between experiments performed on agar plates and those performed in solution and in limestone In a second step the influence of temperature on the performance of the biodeposition treatment with different ureolytic microorganisms was evaluated both on the consolidative and protective effect of the treatment In contrast with the experiments on agar plates the Sporosarcina psychrophila strains failed to produce significant amounts of calcium carbonate on limestone in conditions relevant for practice even at 10 °C This resulted in a poor performance of the treatment From experiments performed on limestone prisms it appeared that the mesophilic Bacillus sphaericus produced the highest amount of carbonate in the shortest amount of time at all temperatures tested As a result compared to the untreated specimens the highest consolidative 64 lower weight loss upon sonication and protective effect 46 decreased sorptivity were observed for the treatments with this species From this study it appears that among all ureolytic strains tested B sphaericus is most suited for biodeposition applications in practiceWillem De Muynck works as a Postdoctoral Fellow of the Flemish agency for Innovation by Science and Technology IWT Flanders Belgium The authors would like to thank Simon De Corte Tom Hennebel and Jianyun Wang for critically reading the manuscript and Linsey Lapeire for assistance during SEM analyses
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