title: Application of alkaliphilic biofilm-forming bacteria to improve compressive strength of cement-sand mortar.
abstract: The application of microorganisms in the field of construction material is rapidly increasing worldwide; however, almost all studies that were investigated were bacterial sources with mineral-producing activity and not with organic substances. The difference in the efficiency of using bacteria as an organic agent is that it could improve the durability of cement material. This study aimed to assess the use of biofilm-forming microorganisms as binding agents to increase the compressive strength of cement-sand material. We isolated 13 alkaliphilic biofilmforming bacteria (ABB) from a cement tetrapod block in the West Sea, Korea. Using 16S RNA sequence analysis, the ABB were partially identified as Bacillus algicola KNUC501 and Exiguobacterium marinum KNUC513. KNUC513 was selected for further study following analysis of pH and biofilm formation. Cement-sand mortar cubes containing KNUC513 exhibited greater compressive strength than mineral-forming bacteria (Sporosarcina pasteurii and Arthrobacter crystallopoietes KNUC403). To determine the biofilm effect, Dnase I was used to suppress the biofilm formation of KNUC513. Field emission scanning electron microscopy image revealed the direct involvement of organic-inorganic substance in cement-sand mortar.
authors.affiliation: School of Life Sciences and Institute for Microorganisms, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Sung-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Woo-Young
authors.initials: WY
authors.lastname: Chun
authors.forename: Wha-Jung
authors.initials: WJ
authors.lastname: Kim
authors.forename: Sa-Youl
authors.initials: SY
authors.lastname: Ghim
mesh_terms: D000468:Alkalies / Q000378:metabolism; D001419:Bacteria / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D018407:Bacterial Physiological Phenomena; D018441:Biofilms; D019245:Compressive Strength; D060389:Construction Industry / Q000295:instrumentation / Q000379:methods*; D003252:Construction Materials / Q000032:analysis* / Q000382:microbiology*; D008969:Molecular Sequence Data; D012623:Seawater / Q000382:microbiology; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D000468:Alkalies; D012822:Silicon Dioxide