Assessment and Characterization of Rhizo-Bacteria in Petroleum–Polluted Soil in South–East, Nigeria

Abstract

A rhizoremediation study was carried out on petroleum-polluted soil in Akiri, Imo State, Nigeria.

The assessment and characterization of bacteria capable of degrading hydrocarbons were isolated from the rhizosphere of Mimosa pudica, Alchornia chordifolia, Chromolaena ordorata, Chloris pilosa and Sida acuta. The isolates identified include Acinetobacter, Bacillus, Micrococcus, and Pseudomonas spp. All the isolates grew on petroleum hydrocarbon at different growth rates. Statistical analysis showed no significant difference (P>0.05) between the rhizosphere and non-rhizosphere of total culturable heterotrophic and hydrocarbon-utilizing bacterial counts in both petroleum-polluted and unpolluted (control) soils. All the plants exhibited positive rhizosphere effects on the rhizo-bacteria. Based on these results, the rhizo-bacteria isolated can serve as seeds for bioaugmentation during remediation of crude oil polluted soil environment. The plants may be employed in rhizoremediation of oil polluted soil.

Keywords: Characterization, Rhizoremediation, Bacteria, Rhizosphere effect, Petroleum-polluted soil