title: Isolation and identification of Pseudomonas azotoformans for induced calcite precipitation.
abstract: Biomineralization is a process by which living organisms produce minerals. The extracellular production of these biominerals by microbes has potential for various bioengineering applications. For example, crack remediation and improvement of durability of concrete is an important goal for engineers and biomineral-producing microbes could be a useful tool in achieving this goal. Here we report the isolation, biochemical characterization and molecular identification of Pseudomonas azotoformans, a microbe that produces calcite and which potentially be used to repair cracks in concrete structures. Initially, 38 bacterial isolates were isolated from soil and cements. As a first test, the isolates were screened using a urease assay followed by biochemical tests for the rate of urea hydrolysis, calcite production and the insolubility of calcite. Molecular amplification and sequencing of a 16S rRNA fragment of selected isolates permitted us to identify P. azotoformans as a good candidate for preparation of biotechnological concrete. This species was isolated from soil and the results show that among the tested isolates it had the highest rate of urea hydrolysis, produced the highest amount of calcite, which, furthermore was the most adhesive and insoluble. This species is thus of interest as an agent with the potential ability to repair cracks in concrete.
authors.affiliation: Faculty of Engineering, Azarbijan Shahid Madani University, Tabriz, Iran. siamak.civil100@gmail.com.
authors.forename: Siamak
authors.initials: S
authors.lastname: Heidari Nonakaran
authors.affiliation: Biotechnology Department, Agriculture Faculty, Azarbijan Shahid Madani University, Km 35 Tabriz-Azarshahr Road, Tabriz, Iran. pazhouhandeh@gmail.com.
authors.forename: Maghsoud
authors.identifier: http://orcid.org/0000-0003-1640-8169
authors.initials: M
authors.lastname: Pazhouhandeh
authors.affiliation: Faculty of Engineering, Azarbijan Shahid Madani University, Tabriz, Iran. abdullahkeyvani@gmail.com.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Keyvani
authors.affiliation: Biotechnology Department, Agriculture Faculty, Azarbijan Shahid Madani University, Km 35 Tabriz-Azarshahr Road, Tabriz, Iran. zahra.abdollahi90@yahoo.com.
authors.forename: Fatemeh Zahra
authors.initials: FZ
authors.lastname: Abdollahipour
authors.affiliation: Biotechnology Department, Agriculture Faculty, Azarbijan Shahid Madani University, Km 35 Tabriz-Azarshahr Road, Tabriz, Iran. ashirzad98@yahoo.com.
authors.forename: Akbar
authors.initials: A
authors.lastname: Shirzad
mesh_terms: D002119:Calcium Carbonate / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D003252:Construction Materials / Q000032:analysis / Q000382:microbiology*; D004783:Environmental Microbiology; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D011549:Pseudomonas / Q000201:enzymology / Q000302:isolation & purification* / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D014508:Urea / Q000378:metabolism; D014510:Urease / Q000096:biosynthesis / Q000378:metabolism
chemical_list: D012336:RNA, Ribosomal, 16S; D014508:Urea; D010088:Oxidoreductases; D002374:Catalase; D014510:Urease; D002119:Calcium Carbonate
keywords: Calcite production; Concrete; Crack remediation; Pseudomonas