Screening and Characterization of Calcite Solubilizing Bacteria isolated from Marble Slurry dumped in Sukher, Udaipur, Rajasthan, India

Abstract

Rajasthan is known as mineral majestic state as more than 50 types of minerals are produced including marble. Various types of marbles are spread over in 16 belts in 33 districts of the State. Large amount of marble slurry is discharged as a waste generated by the quarries which is dumped in empty pits in the forest area; thereby creating huge dumping area. The present study was undertaken for screening and characterization of calcite solubilizing bacteria from marble slurry collected from dumping yard in Sukher, Udaipur, India. Screening of calcite solubilizing bacteria was done on calcite agar medium. Calcite solubilizing efficiency (CSE) and calcite solubilizing activity index (CSAI) of the isolates were determined using 0.1% calcite agar medium at 37C for 10 days of incubation. Characterization of the isolates was done on the basis of morphological, biochemical and molecular methods. A total of 27 isolates appeared on calcite agar medium after an incubation of 24 hours at 37°C. Among them only 3 isolates namely isolate CS6, CS13 and CS25 showed clear halo zone of 20 mm, 29 mm and 2mm diameters respectively after 10 days of incubation indicating demonstrable calcite solubilizing activity. The maximum CSE and CSAI 362% and 4.62 respectively were observed for isolate CS13. Isolates CS6, CS13 and CS25 were identified as Exiguobacterium aquaticum CS6 (accession no. MK353511), Staphylococcous aureus CS13 (accession no. KY694446) and Bacillus endophyticus CS25 (accession no. MK353513) respectively. Two isolates that showed remarkable calcite solubilizing activity can be further analyzed for their possible use in restoration of marble slurry contaminated soil.