Ahmad, Wan Azlina and Zakaria, Zainul Akmar and Zakaria, Zainoha and Surif, Salmijah (2009) Hexavalent chromium reduction at different growth phases of acinetobacter haemolyticus. Environmental Engineering Science, 26 (7). pp. 1275-1278. ISSN 1092-8758
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Official URL: http://dx.doi.org/10.1089/ees.2008.0359
The aim of this work was to evaluate the effects of hexavalent chromium [Cr(VI)] addition at different growth phases on the Cr(VI) reducing capacity of the aerobic Gram-negative bacterium, Acinetobacter haemolyticus. The addition of 10-100 mg Cr(VI) L-1 as potassium dichromate at the time of inoculation (T0) resulted in the extension of time needed to reach the stationary phase, with a total growth inhibition at 70mg Cr(VI) L-1, a decrease in bacterial count from 108 to 102 CFU mL -1, and a Cr(VI) reduction drop to 35% at 100mg Cr(VI) L -1. However, bacterial growth was uninterrupted when 10-100mg Cr(VI) L-1 were added at the early stationary phase (after 12h of bacterial growth) indicated by a high bacterial count of 108 CFU mL -1. More than 95% of Cr(VI) was reduced at an initial Cr(VI) of 50mg L-1. However, the Cr(VI) reduction capacity dropped to 50% at 100 mg Cr(VI) L-1. This study showed that the ability of Acinetobacter haemolyticus to reduce Cr(VI) depends strongly on the number of surviving cells present in the solution. Higher Cr(VI) reduction can be achieved when a high number of bacterial cells are present. To achieve this condition, it is suggested to introduce the Cr(VI) into cells suspension at the stationary phase rather than introducing the Cr(VI) at the time of inoculation.
|Uncontrolled Keywords:||acinetobacter, chromium, growth, reduction, time|
|Subjects:||Q Science > QD Chemistry|
|Deposited By:||Ms Zalinda Shuratman|
|Deposited On:||30 Sep 2011 15:15|
|Last Modified:||30 Sep 2011 15:15|
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