Biodegradative Potentials of Phytase-producing Bacterial Isolates Recovered from Spent Engine Oils Polluted-Soils

Abstract

Microbial remediation of environmental contaminants such as spilled and used petroleum products is an increasing auspicious technique, owing to its associated low-cost and eco-friendly outcomes compared to other methods. For this purpose, recovered bacteria isolates from contaminated soils in automobile workshops were screened for phytase activity and hydrocarbon biodegradative ability. Presumptive bacterium with inherently high phytase activity and biodegradative potential was further characterized using 16S rRNA gene sequence analysis. Soil total petroleum hydrocarbon (TPH) was determined using gas chromatographic technique (GC-FID). The identities of the isolates recovered from the samples include; Bacillus subtilis, B. licheniformis, Pseudomonas aeruginosa, Escherichia coli, Corynebacterium variabilis, Micrococcus luteus and Proteus vulgaris. Of all the isolates, P. aeruginosa had the highest phytase activity after 48 h of incubation whereas, P. vulgaris recorded the least phytase activity. E. coli and B. subtilis showed active phytase activity at pH 5.0 and 40°C. While P. aeruginosa exhibited proficient degrading ability on crude oil and spent engine oil at all days of incubation, E. coli and C. variabilis showed the most inaptitude. The 16S rRNA gene analysis shows that the isolate obtained from the automobile workshop is of the genus P. aeruginosa with reference to ATCC 27853. The TPH of the contaminated soils ranged from 545,168 to 856,328 Mg/kg. This study reveals the degradative potential of P. aeruginosa as suitable candidate in bioremediation of crude oil contaminated sites.