Locally Isolated Bacterial Strains with Multiple Degradation Potential Capabilities on Petroleum Hydrocarbon Pollutants

Abstract

In the present study, 23 isolates, dominated by bacterial genera (74%) were isolated from petroleum sludge at refinery wastewater plant, Jeddah, KSA, by means of selective enrichment in nutritionally optimized refinery wastewater (NORWW) and over twelve successive transfers. Efficiency of biodegradation on complex mixture of hydrocarbons present in refinery wastewater was evidenced by changes in both total viable counts (TVC) and COD content of cultivation broth. Out of the 23 isolates three most potent isolates named BDCC-TUSA-8, BDCC-TUSA-12 and BDCC-TUSA-18 were selected for their efficient COD removal and active growth. The three isolates were tested separately in Bushnell-Haas (BH) media for their capabilities to degrade n-Hexadecane, phenol and phenanthrene, representing the major types of hydrocarbon pollutants. The results strongly indicated that all three isolates showed multiple degradation potentials with remarkably fast reaction rates. Before being recom mended for future work, the three isolates were fully characterized and identified employing culture-dependent techniques such as API 20E, API 20NE and API 50CHB, and further confirmed by partial 16S rRNA gene sequencing and phylogenetic analysis as Pantoea agglomerans , Acinetobacter lwoffii and Bacillus thuringiensis respectively. The obtained potent strains provide valuable candidates if assemblages of mixed fewer strains with overall broad and complementary enzymatic capacities are to be considered in order to bring the rate and extent of petroleum biodegradation further as a cost-effective process.