title: Calcite Dissolution byBrevibacteriumsp. SOTI06: A Futuristic Approach for the Reclamation of Calcareous Sodic Soils.
abstract: Assessing the ability of soil microorganisms to dissolute poorly soluble native calcite to supply Ca2+is a new area to be explored in reclaiming sodic soils by supplying adequate Ca2+and reducing the recurrent sodicity. Hence, the present study aimed to isolate a calcite dissolving bacteria (CDB) from calcareous sodic soils and to understand the mechanism of calcite dissolution. Of the 33 CDB isolates recovered from the calcareous sodic soils of Tamil Nadu (Coimbatore, Ramnad, and Trichy), 11 isolates were screened for calcite dissolution based on titratable acidity. 16S rRNA gene sequence analysis of the three best isolatesviz., SORI09, SOTI05, and SOTI06 revealed 99% similarity toBacillus aryabhattai, 100% toB. megaterium, and 93% toBrevibacteriumsp., respectively. Among them,Brevibacteriumsp. SOTI06 released more Ca2+(3.6 g.l-1) by dissolving 18.6% of the native calcite. The spectral data of FTIR also showed reduction in the intensity of calcite (55.36-41.27) by the isolate at a wave number of 1636 cm-1which confirmed the dissolution. Besides producing organic acids (gluconic acid and acetic acid),Brevibacteriumsp. SOTI06 also produced siderophore (91.6%) and extracellular polysaccharides (EPS, 13.3 μg. ml-1) which might have enhanced the calcite dissolution.
authors.affiliation: Biocatalysts Lab, Department of Agricultural Microbiology, Tamil Nadu Agricultural University Coimbatore, India.
authors.forename: S M
authors.initials: SM
authors.lastname: Tamilselvi
authors.affiliation: Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University Coimbatore, India.
authors.forename: Chitdeshwari
authors.initials: C
authors.lastname: Thiyagarajan
authors.affiliation: Biocatalysts Lab, Department of Agricultural Microbiology, Tamil Nadu Agricultural University Coimbatore, India.
authors.forename: Sivakumar
authors.initials: S
authors.lastname: Uthandi
keywords: Brevibacterium sp.; calcareous soils; calcite dissolution; in-vitro analysis; sodicity reclamation