RESUMO
Two strains of Bacillus sp. resistant to arsenate and lead designated as AsSP9 and PbSP6, respectively were isolated from the slag disposal site. They were identified to be related to Bacillus cereus cluster on the basis of 16S rDNA based sequence analysis and phenotypic characteristics. Both were rod-shaped (AsSP9, 2-5 μm and PbSP6, 2-4 μm), aerobic, salt tolerant (2-8% NaCl), endospore forming bacteria with minor differences like the AsSP9 showed sporangial bulging and PbSP6 had positive lipase activity. The temperature range for their growth was 20-40oC and pH range 6.0-9.0 with an optimum temperature of 37oC and pH of 7 for both strains. The principal nitrogen sources for AsSP9 and PbSP6 were DL-Tryptophan and L-Phenylalanine, respectively. The suitable carbon source for AsSP9 was lactose and for PbSP6 sucrose. The heavy metal accumulation efficiency was found to be 0.0047 mg g-1 of dry mass for AsSP9 and 0.686 mg g-1 of dry mass for PbSP6.