Removal of lead and inhibition of algal growth using prodigiosin produced by Serratia marcescens

Abstract

This study examined the removal of lead and inhibition of Anabaena sphaerica and Oscillatoria agardhii growth using prodigiosin produced by Serratia marcescens. Inhibition of the algal growth was studied by the addition of different concentration of prodigiosin 50μl, 100μl, 150μl in 90ml of algal culture. Control was without the pigment prodigiosin. Inhibition rates were determined at the interval of 72 hours of incubation using spectrophotometer. A.sphaerica record highest level of inhibition in all concentration of prodigiosin which was 76.7%, while O.agardhii was 66.3% at the same concentration. At concentration of 50μg/L, A.sphaerica record of 66.3% inhibition with O.agardhi 67.2% and 66.5% respectively. Statically analysis shows no significant differences between the rate of inhibition by the two algal species studied but there was significant difference between concentration of prodigiosin and and the rate of inhibition. Removal of lead polluted soil sample was studied by the addition of different concentration of prodigiosin 50μl, 100μl, 150μl to 5g of lead polluted soil in 90ml of distilled water. The lead removal rate was determined at the interval of 4 weeks of incubation for six months using atomic absorption spectroscopy (AAS). The rate shows that 100ul of prodigiosin enhance high amount of lead removal from soil. The amount of lead immobilized by the pigment at 20 stable after 24 weeks. This was followed by 50μL and 150μL of prodigiosin in which there was immobilization of 41.2% and 35.3% respectively at 20 weeks of treatment. The results suggest that the red pigment inhibited cyanobacteria growth and be used as a potential for the removal of soil polluted with lead.