title: Pyrosequencing reveals correlations between extremely acidophilic bacterial communities with hydrogen sulphide concentrations, pH and inert polymer coatings at concrete sewer crown surfaces.
abstract: OBJECTIVE
  To investigate the acidophilic bacterial communities involved in microbially induced concrete corrosion (MICC).
  
  
  RESULTS
  Our study sites located downstream from a forced main provided a unique opportunity to study the microbial communities involved in MICC under different environmental conditions (gradients of atmospheric H(2)S, sulphate concentration and pH) and under pipe modifications (coated vs uncoated). Bacterial cell density estimated by both cultivation- and DNA-based methods was low in the corroded sewer samples. Pyrosequencing and cloning showed that Mycobacterium and Acidithiobacillus dominated the acidophilic microbial communities. Methylacidiphilum was also dominant in samples where methane was detected. Correlation analysis indicated that Mycobacterium and Acidithiobacillus were significantly affected by pH and that Mycobacterium could better withstand highly acidic conditions compared to Acidithiobacillus.
  
  
  CONCLUSIONS
  Communities dominated by Mycobacterium favoured conditions in the lined sewer pipes, while communities with a higher relative abundance of Acidithiobacillus favoured the unlined sewer pipes.
  
  
  CONCLUSIONS
  Identifying the key micro-organisms involved in MICC and knowing how they interact with their environment are essential aspects for identifying steps towards concrete corrosion management.
authors.affiliation: Department of Civil and Environmental Engineering, University of Hawai'i at Mānoa, Honolulu, HI, USA.
authors.forename: E
authors.initials: E
authors.lastname: Pagaling
authors.forename: K
authors.initials: K
authors.lastname: Yang
authors.forename: T
authors.initials: T
authors.lastname: Yan
mesh_terms: D042763:Acidithiobacillus / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D003343:Corrosion; D005798:Genes, Bacterial; D059014:High-Throughput Nucleotide Sequencing; D006862:Hydrogen Sulfide / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008420:Manufactured Materials; D059013:Microbial Consortia / Q000235:genetics; D009161:Mycobacterium / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012722:Sewage / Q000382:microbiology*
chemical_list: D012336:RNA, Ribosomal, 16S; D012722:Sewage; D006862:Hydrogen Sulfide
keywords: acidophilic; concrete corrosion; hydrogen sulphide; mycobacteria