Journal of Applied Microbiology ISSN 1364-5072
ORIGINAL ARTICLE
Proposal of biostimulation for hexachlorocyclohexane (HCH)-decontamination and characterization of culturable bacterial community from high-dose point HCH-contaminated soils M. Dadhwal1, A. Singh1, O. Prakash1, S.K. Gupta1, K. Kumari1, P. Sharma1, S. Jit1, M. Verma1, C. Holliger2 and R. Lal1 1 Department of Zoology, University of Delhi, Delhi, India 2 EPFL, ENAC-ISTE, Laboratory of Environmental Biotechnology, Lausanne, Switzerland
Keywords biostimulation, hexachlorocyclohexane, sphingomonads. Correspondence Rup Lal, Department of Zoology, University of Delhi, Delhi 110 007, India. E-mail:
[email protected]
2007 ⁄ 1324: received 19 August 2007, revised 28 March 2008 and accepted 25 May 2008 doi:10.1111/j.1365-2672.2008.03982.x
Abstract Aims: To locate a high-dose point hexachlorocyclohexane (HCH)-contaminated site, to identify HCH-degrading bacteria in it and assay HCH-decontamination by biostimulation. Methods and Results: Bacteria were isolated by serial dilution method from HCH-contaminated soil samples collected from areas near an HCH-manufacturing unit and its dumpsite in North India. After confirming the presence of indigenous HCH-degraders (seven of 24 strains), an ex situ biostimulation experiment was conducted. For this, residue levels in soil were diluted by mixing with pristine garden soil and aeration, moisture and nutrients were provided intermittently. This soil was monitored for reduction in R-HCH (sum of a-, b-, c- and d-HCH) levels and stimulation of HCH-degraders. Experiments were conducted twice, in March–April (c. 75 lg R-HCH g)1 soil) and October–November 2006 (c. 280 lg R-HCH g)1 soil) at 26–30C. R-HCH levels were reduced to
