A study on phosphate uptake by <i>Acinetobacter </i> sp. in presence of arsenate under aerobic condition

Abstract

Phosphate is the main hindrance for the removal of arsenic from the arsenic contaminated waste water.Therefore, phosphate removal from contaminated water has become imperative for the successful removal of arsenic. In the present study, an attempt was made to remove phosphate from the waste water by <i>Acinetobacter </i> sp.in the presence and absence of arsenate. When phosphate (25 ppm) containing synthetic solution was treated with <i>Acinetobacter </i> sp.at pН 6 at ambient temperature under aerobic condition, the bacterium was able to remove 71.88% (17.97 ppm) phosphate. However, in the presence of arsenate (5 ppm), only 54.24% (13.56 ppm) phosphate uptake was observed from the waste water by <i>Acinetobacter </i> sp. Thus the presence of arsenate (5 ppm) inhibited phosphate uptake by 17.64%. The phosphate uptake by <i>Acinetobacter </i> sp. follows the Michalis-Menten kinetics. In the presence and absence of arsenate, the maximum velocity (<i>V</i>_max) of phosphate uptake was 1.07 and 1.03 µM mg⁻¹ h⁻¹; while the kinetic constant (<i>K</i>_m) was 1.13 and 0.37 mM, respectively. Consequently, arsenate was observed as competitive inhibitor for the phosphate uptake. The data thus underlines the significance of <i>Acinetobacter</i> sp. for the removal of phosphate along with arsenate.