title: Carbonate precipitation under pressure for bioengineering in the anaerobic subsurface via denitrification.
abstract: A number of bioengineering techniques are being developed using microbially catalyzed hydrolysis of urea to precipitate calcium carbonate for soil and sand strengthening in the subsurface. In this study, we evaluate denitrification as an alternative microbial metabolism to induce carbonate precipitation for bioengineering under anaerobic conditions and at high pressure. In anaerobic batch culture, the halophile Halomonas halodenitrificans is shown to be able to precipitate calcium carbonate at high salinity and at a pressure of 8 MPa, with results comparable to those observed when grown at ambient pressure. A larger scale proof-of-concept experiment shows that, as well as sand, coarse gravel can also be cemented with calcium carbonate using this technique. Possible practical applications in the subsurface are discussed, including sealing of improperly abandoned wells and remediation of hydraulic fracturing during shale gas extraction.
authors.affiliation: School of Geosciences, Grant Institute, University of Edinburgh , The King's Buildings, Edinburgh EH9 3JW, UK. d.martin@ed.ac.uk
authors.forename: Derek
authors.initials: D
authors.lastname: Martin
authors.forename: Kevin
authors.initials: K
authors.lastname: Dodds
authors.forename: Ian B
authors.initials: IB
authors.lastname: Butler
authors.forename: Bryne T
authors.initials: BT
authors.lastname: Ngwenya
mesh_terms: D000693:Anaerobiosis; D001709:Biotechnology; D002119:Calcium Carbonate / Q000737:chemistry*; D002384:Catalysis; D058440:Denitrification; D020632:Halomonas / Q000378:metabolism; D011312:Pressure
chemical_list: D002119:Calcium Carbonate