Bioremediation of Heavy Metals from Crude 0il Polluted Soil Using Serratia marcescens and its Toxicology Assessment on Aquaculture

Abstract

Serratia marcescens has been studied to show a higher degradation potential for organo-phosphorus pesticides. This property has made it useful as a potential bioremediation agent. The bacterial cell was bio-stimulated in luria beterni broth at a selected experimental temperature ranging from 25 ºC – 40 ºC. The highest cell biomass was recorded at 35 ºC to range from 7.56 -8.10mg/ml for single strength and double strength yeast extract in luria beterni, respectively. Percentage bio-sorption efficiency of both the cell culture and extracted membrane protein augmented cell culture of Serratia marcescens showed 100% removal in heavy metals such as lead, potassium and manganese, respectively. The cell culture percentage sorption also showed 99.2%, 95.9% and 82% removal of copper, nickel and zinc, respectively, while the protein extract augmented cell culture showed improved corresponding heavy metal removal with 100% removal of copper and nickel and 86.5% removal of zinc. The bacterial cell and corresponding protein extracts tend to create oxygen stress in an aquaculture model, reducing the dissolved oxygen level to 3 mg/l. Lethal dose 50 of the bacterial extracts were high a 14.14%; hence this showed high toxicity or pathogenicity of the bacteria. This showed that the bacterial cell and corresponding proteins extract showed promising in the removal of heavy metals in an aquaculture environment; however, its toxicity effect on the test fishes makes it a potential risk to aquatic life.