The potential of Serratia marcescens in bioremediation of crude-oil polluted soil

Abstract

Bioremediation, which involves the use of microorganisms, is an environmentally friendly approach in restoring crude-oil polluted environments. The use of Serratia marcescens (SM) in bioremediation of crude-oil polluted soil was investigated in this study. Soil from a farm was inoculated in nutrient broth for bacterial enrichment. The broth culture was inoculated on nutrient agar and incubated at ambient temperatures (27 – 32 °C). Bacterial isolates with red colonies were selected and identified. Identified SM was used in preparing bacterial mineral-salts suspension. The bioremediation experiment consisted of two setups: Control (CT) and setup treated with SM (TSM). Both setups contained crude-oil polluted soil. Mineral salt solution and the bacterial-mineral-salt suspension were added to setup CT and TSM, respectively. Total hydrocarbon concentration (THC), total heterotrophic bacteria (THB), hydrocarbon utilizing bacteria (HUB), total fungi (TF), and hydrocarbon utilizing fungi (HUF) in the setups were determined at various times. About 38.3 % and 46.5 % THC reduction were achieved in setup CT and TSM, respectively. The percentage of THB that are HUB was higher in setup TSM on day 7 (8.8 %) and day 28 (4.4 %) but higher in setup CT on day 14 (1.7 %) and day 21 (6.6 %). The percentage of TF that are HUF was higher in setup TSM on day 14 (98.0 %) and on day 28 (41.6 %) but higher in setup CT on day 21 (85.3 %). It is concluded that SM has a potential for use in bioremediation of crude-oil polluted soil.