Brazilian Archives of Biology and Technology (Aug 2014)
Characterization and Metal Detoxification Potential of Moderately Thermophilic Bacillus cereus from Geothermal Springs of Himalaya
Abstract
Two thermophilic Bacillus cereus strains (B. cereus-TA2 and B. cereus-TA4) used in the present study were isolated from the geothermal spring of Hunza valley, Gilgit, Pakistan. They showed the ability to withstand and grow at high temperature (85°C). Both these strains could resist multiple metals (copper, cadmium, mercury, manganese, zinc, arsenic, chromium and selenium). Strain B. cereus-TA4 reduced Cr (VI) at pH 5.0 to 9.0 but maximum reduction (83%) was observed at pH 7.0 after 48 h when initially supplied with 200 µg mL-1of K2CrO4. Lower initial concentrations such as 100 µg mL-1 supported higher reduction (90 to 95%) than that of high concentration such as 500 µg mL-1 (20 to 30%). Both the strains reduced nearly 70% of Se (IV) after 48 h of growth at pH 7.0 when initially supplied with 200 µg mL-1 of Na2SeO3. The optimum temperature for maximum Se (IV) reduction was 45°C for both the strains.
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