Bio-cleaning of nitrate salt efflorescence on stone samples using extremophilic bacteria

Sci Rep. 2019 Feb 7;9(1):1668. doi: 10.1038/s41598-018-38187-x.


For the first time, we propose the use of an extremophilic bacterium to remove nitrate salt efflorescence from the surfaces of stone samples. A haloalkaliphilic bacterium was selected "ad hoc" for its ability to reduce nitrates; i.e. Halomonas campaniensis sp. nov., strain 5AGT (DSM 15293T, ATCC BAA-966T). Quantitative monitoring of nitrate content, on untreated and treated surfaces of stone samples artificially enriched with nitrate, as a function of incubation/treatment time, was carried out by molecular spectroscopy. The results obtained reveal the good performance of Halomonas campaniensis bacterium in decreasing nitrate concentration on stone surfaces both in a controlled laboratory environment for temperature and relative humidity and in a real outdoor environmental conditions.

MeSH terms

  • Biodegradation, Environmental*
  • Biotechnology
  • Construction Materials*
  • Environmental Pollutants / isolation & purification
  • Environmental Pollutants / metabolism
  • Halomonas / growth & development*
  • Halomonas / metabolism
  • Nitrates / isolation & purification*
  • Nitrates / metabolism*
  • Silicon Dioxide / chemistry*


  • Environmental Pollutants
  • Nitrates
  • granite
  • Silicon Dioxide