Abstract:
Restoration of polycyclic aromatic hydrocarbon- (PAH-) polluted sites is presently amajor challenge in agroforestry. Consequently,
microorganisms with PAH-degradation ability and soil fertility improvement attributes are sought after in order to achieve
sustainable remediation of polluted sites. This study isolated PAH-degrading bacteria from enriched cultures of spent automobile
engine-oil polluted soil. Isolates’ partial 16S rRNA genes were sequenced and taxonomically classified. Isolates were further
screened for their soil fertility attributes such as phosphate solubilization, atmospheric nitrogen fixation, and indoleacetic
acid (IAA) production. A total of 44 isolates were obtained and belong to the genera Acinetobacter, Arthrobacter, Bacillus,
Flavobacterium, Microbacterium, Ochrobactrum, Pseudomonas, Pseudoxanthomonas, Rhodococcus, and Stenotrophomonas. Data
analysed by principal component analysis showed the Bacillus and Ochrobactrum isolates displayed outstanding IAA production.
Generalized linear modelling statistical approaches were applied to evaluate the contribution of the four most represented genera
(Pseudomonas, Acinetobacter, Arthrobacter, and Rhodococcus) to soil fertility. The Pseudomonas isolates were the most promising
in all three soil fertility enhancement traits evaluated and all isolates showed potential for one or more of the attributes evaluated.
These findings demonstrate a clear potential of the isolates to participate in restorative bioremediation of polluted soil, which will
enhance sustainable agricultural production and environmental protection.
