Abstract

Isolation and Characterization of Arsenic Resistant Bacteria from Contaminated Soil

Author(s): Ananda Kumar Saha1, Sk. Md. Atiqur Rahman2,Moni Krishno Mohanta*3Md. Fazlul Haque4, Saila Naz5andRokshana Ara Ruhi6

Arseniccontamination in soil is a serious problem in Bangladesh. The soil bacteria which are re-sistantto arsenic can play an important role in reduction of arsenic toxicity of soil. Hence, the aim of the study was to isolate arsenic resistant bacteria from arsenic contaminated soil. A total of three arsenic resistant bacteria viz.PB1, PB2 and PB3 were isolated from the suspension of arsenic contaminated soil inoculated in Basal salt media with 40 mM sodium-arsenate at 37°C under aerobic condition. The optimum growth of PB1 and PB2 were observed at 37°C while PB3 showed maximum growth at 30°C. PB2 and PB3 showed optimum growth at pH 9 while the max-imum growth of PB1 was observed at pH 7. The MIC results showed that PB1,PB2 and PB3were resistant up to 8mM and 16mM As(III)respectively. However,the all isolates showed resistance up to 256mM As(V). Analysis of 16S rRNA gene sequences revealed that isolate PB1, PB2 and PB3 were similar to Agrobacteriumsp. PAE1(99%), Brevibacillus borstelensisstrain 1CK49 (99%) and Ochrobactrumsp. DS4(99%) respectively.

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