Use of Indigenous Bacteria from Arsenic Contaminated Soil for Arsenic Bioremediation - Management of Natural Resources in a Changing Environment - page 150

many procedures have been documented earlier (US EPA 2002 ). The need for low-
cost and eco-friendly technologies for removing As from the environment is recently
being emphasized. For survival under metal-stressed conditions, microorganisms
have evolved several resistance mechanisms like exclusion, intra- and extra-cellular
complexation, precipitation, volatilization, enzymatic oxidation/reduction, and
adsorption (Nies 1999 ). Microbial isolates having either of the mechanisms would
be useful to select a possible As bioremediating candidate.
The aim of the present study was to fi nd an arsenic resistant indigenous bacterial
isolate from paddy fi eld rhizosphere soil irrigated with As-containing groundwater,
which could effectively remove arsenic under aerobic culture condition and that can
be used for bioremediation without the need for pre-processing. We found a
Brevibacillus sp. strain KUMAs1, capable of removing arsenic, suggesting the pos-
sibility that it could be used for bioremediation of arsenic.
Methodology
Rhizosphere soil of paddy fi eld, Nadia District, West Bengal, India (Fig. 1 ), was
collected in sterile container to avoid any contamination. The pH value and organic
carbon content of the soil sample were determined following standard method
(Walkley and Black 1947 ; ASA 1982 ). Total As content in the soil sample was mea-
sured after acid digestion and was quantifi ed by atomic absorption spectroscopy
(AAnalyst 400, Perkin Elmer, Singapore).
Fig. 1 Geographic location of arsenic resistant bacterial strain KUMAs1 isolation site