Bioremediation Potential of Selected Rhizosphere Fungi of Tridax Procumbens Linn. and Chromolaena odorata (L.) R.M. King & H. Rob

Abstract

Co-metabolism between plants and rhizosphere microbes is the mainstay of rhizoremediation of contaminated soils. The aim of the current study was to isolate and screen selected rhizosphere micro-fungi of two Asteraceae (Tridax procumbens and Chromolaena odorata) collected from the wild in University of Lagos, Akoka, Lagos State for bioremediation potential. Rhizosphere fungi were isolated, identified and evaluated for crude oil myco-remediation. The inhibitory effect of different concentrations of crude oil on mycelial growth of the most abundant fungi was determined with poisoned plate assay method. The most abundant and recurring fungi around C. odorata and T. procumbens were determined using the serial dilution and plating methods. Analysis of the rhizosphere soil of T. procumbens and C. odorata showed they were sandy loam type. C. odorata soil had higher moisture, organic carbon, and acid content than T. procumbens. Aspergillus flavus and Trichoderma harzianum were the most abundant and recurring fungi in C. odorata and T. procumbens, respectively. Thirty-nine micro-fungi belonging to twenty genera were isolated from the test plants’ rhizosphere. A. flavus and T. harzianum tolerated 2.50 to 10.00% crude oil contamination assessed with their mycelial growth inhibition reducing with time. A. flavus and T. harzianum caused a 68.45% and 86.71% reduction of crude oil contamination respectively, in a time dependent manner. The filamentous fungi ~A. flavus and T. harzianum can potentially be used to simultaneously ameliorate crude oil contaminated soils in conjunction with C. odorata and T. procumbens, respectively in the innovative technology termed rhizoremediation.