Isolation and characterization of bacteria with arsenic tolerance from garden soil and their potential role in soil biology

Tamanna Zerin; Md Borhan Uddin; Sharmin Ahmed; Maliha Sharmin; Sourav Sarkar; Farzana Yasmin Shomi; Ehsan Al-din Siam

Isolation and characterization of bacteria with arsenic tolerance from garden soil and their potential role in soil biology

Authors
Tamanna Zerin, Md Borhan Uddin, Sharmin Ahmed, Maliha Sharmin, Sourav Sarkar, Farzana Yasmin Shomi, Ehsan Al-din Siam

Abstract
Arsenite (III) is the most toxic form of arsenic salt that is a widespread concern in many developing countries. Our study was carried out primarily to detect arsenite tolerance level of bacteria isolated from garden soil of Stamford University Bangladesh. Only 8 bacterial isolates were presumptively isolated and identified as Bacillus spp. (C1, C3, and D3), Staphylococcus spp. (C6, D2, and D6) and Moraxella spp. (D4, and D7) with 0.5 mg/ml concentration of arsenite tolerence. However, only five isolates including Bacillus spp. (C1, C3, and D3), and Staphylococcus spp. (D2 and D6) were able to convert highly toxic arsenite to less toxic arsenate. Amongst, isolate C1 (Bacillus sp.) showed the highest bioconversion in vitro. Those 5 isolates showed minimum inhibitory concentration (MIC) from 1 to 4 mg/ml and minimum bactericidal concentration (MBC) from 4 to 16 mg/ml for arsenite salt. Moreover, MIC and MBC of NaCl salt were ranged from 1.7% to 3.4% and 1.7% to 6.8%, respectively. None of those isolates showed any role in ammonification, nitrification and nitrogen fixation. A degree of drug resistance was observed against those 8 isolates. Above all, the resident bacterial isolates from garden soil can be examined to distinguish their potential in bioremediation.

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