The conversion of hexavalent molybdenum (Mo (VI)) to Mo-blue is a bioremediation technique
which reduces the toxicity of molybdenum to a less toxic form by bacteria. The aim of this study
is to determine the optimum conditions of significant parameters or variables that affect the
reduction of Mo (VI) to Mo-blue by the local isolate identified as Serratia sp. strain MIE2.
Response Surface Methodology (RSM) was used in this study to optimize the reduction process
using Central Composite Design (CCD) as an optimization matrix. The optimum conditions
predicted by RSM using the desirability function for the reduction process were 20 mM
molybdate concentration, 3.95 mM phosphate, 6.25 pH and 25 g/L glucose and Mo-blue
production occurred at the absorbance value of 20.5 at 865 nm. The validation of the predicted
optimum points showed the Mo-blue production occurred at the absorbance value of 21.85 with
a deviation around 6.6 % from the RSM predicted value.