Identification of a Bacterial Consortium with Biotechnological Potential for Arsenic Bioremediation

Abstract

The objective of this work was to identify one bacterial consortium adapted to the cultivation in the presence of trivalent arsenic (AsIII). Samples were cultured in flasks containing modified Postgate C liquid medium (selective for sulfate-reducing bacteria, SRB). Six different As concentrations were used: 0.5, 1.0, 2.0, 4.0, 8.0 and 16 mg l-1. The growth of sulfate reducing microorganisms was indirectly observed by the formation of an iron sulfide black precipitate and also by the Eh measures.100 ml aliquots of cultured media were centrifuged and stored at-20°C for DNA extraction by phenol/chloroform method. Universal primers 968F-GC 1392R (Bacteria domain) were used for 16S ribosomal DNA amplification. Microbial diversity was evaluated by denaturing gradient gel electrophoresis (DGGE). After DGGE analysis 7 different bands were selected, cut, sequenced and analyzed using the Ribosomal Database Project Release. Consortium microorganisms identified were: Pantoea agglomerans, Enterobacter sp, Citrobacter sp, Cupriavidusmetallidurans, Ralstonia sp, Burkholderia cepacia and Bacillus sp. Thus the microbial consortium here identified is a good candidate for bioremediation of arsenic contaminated areas and effluents.