Biosorption of Pb(II) by Bacillus badius AK strain originating from rotary drum compost of water hyacinth.

The presence of heavy metals in the environment due to industrial activities is of serious concern because of their toxic behaviour towards humans and other forms of life. Biosorption of Pb(II) using dry bacterial biomass of Bacillus badius AK, previously isolated from water hyacinth compost, has been undertaken in batch system. The optimum conditions of biosorption were determined by investigating the initial pH, contact time, initial biomass dosage at constant temperature of 40 °C, initial metal concentration of 100 mg/L and rotational speed of 150 rpm. The optimum pH was found to be 5 and equilibrium contact time was 2.5 h. The maximum biosorption capacity of Pb(II) on Bacillus badius AK was 138.8 mg/g at an initial concentration of 100 mg/L. A kinetics study revealed that the adsorption process followed pseudo second order rate kinetics. The experimental data were fitted to the Langmuir isotherm. Characterization of the biomass indicated the presence of several functional groups. The results indicated that the bacterium Bacillus badius AK is efficient for the removal of Pb(II).

Biosorption of lead using Bacillus badius AK strain isolated from compost of green waste (water hyacinth).

The bacterial strain Bacillus badius AK isolated from water hyacinth compost was investigated for biosorption characteristics in Pb(II) removal. Batch mode experiments depicted the optimum conditions for biosorption as pH at 4, the temperature of 30°C, 150 rpm of the rotational speed at biomass concentration of 20 mL with 1.7 × 1016 colony forming unit per milliliter (CFU/mL) value, at 100-150 mg/L concentration of Pb(II). The bacterial biomass was used in its native and non-pretreated state, unlike the dried, freeze-dried or chemically treated biomass. The biosorption followed pseudo-second-order kinetics and isotherm fitted well to the Langmuir model. Maximum Pb(II) biosorption was observed at 1.7 × 1016 CFU/mL. Influence of Pb(II) on the growth of bacterial biomass was examined by fitting the monod's model. Specific growth rate and maximum specific growth rate of B. badius AK was observed as 0.05 and 2.54 h-1, respectively; biomass yield coefficient was 11.81. The results indicated that bacterial biomass was efficient, robust and cheaper biosorbent for removal of Pb(II).