Biodegradation Ability and Catabolic Genes of Petroleum-DegradingSphingomonas koreensisStrain ASU-06 Isolated from Egyptian Oily Soil

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are serious pollutants and health hazards. In this study, 15 PAHs-degrading bacteria were isolated from Egyptian oily soil. Among them, one Gram-negative strain (ASU-06) was selected and biodegradation ability and initial catabolic genes of petroleum compounds were investigated. Comparison of 16S rRNA gene sequence of strain ASU-06 to published sequences in GenBank database as well as phylogenetic analysis identified ASU-06 as Sphingomonas koreensis. Strain ASU-06 degraded 100, 99, 98, and 92.7% of 100 mg/L naphthalene, phenanthrene, anthracene, and pyrene within 15 days, respectively. When these PAHs present in a mixed form, the enhancement phenomenon appeared, particularly in the degradation of pyrene, whereas the degradation rate was 98.6% within the period. This is the first report showing the degradation of different PAHs by this species. PCR experiments with specific primers for catabolic genes alkB, alkB1, nahAc, C12O, and C23O suggested that ASU-06 might possess genes for aliphatic and PAHs degradation, while PAH-RHDαGP gene was not detected. Production of biosurfactants and increasing cell-surface hydrophobicity were investigated. GC/MS analysis of intermediate metabolites of studied PAHs concluded that this strain utilized these compounds via two main pathways, and phthalate was the major constant product that appeared in each day of the degradation period.

Phenanthrene biodegradation by sphingomonads and its application in the contaminated soils and sediments: A review

“…Earlier reports confirmed these results that sphingomonads are hydrophilic (Kohlmeier et al, 2005) and did not commonly produce significant amounts of surfactants during PAH degradation (Johnsen and Karlson, 2004). However, this is not the case with Sphingomonas koreensis ASU-06, as phenanthrene was solubilized by its rhamnolipid biosurfactant compared to anthracene, though biosurfactant production was seen in anthracene compared to phenanthrene (Hesham et al, 2014). This shows that biosurfactant production occurs in very few sphingomonads, may be as a result of their evolution in the environments they reside in and genetic changes in their genomes.…”

Molecular Characterization of Fusarium Solani Degrades a Mixture of Low and High Molecular Weight Polycyclic Aromatic Hydrocarbons

“…For identification, the ITS region of fungal DNA was amplified Tolerance rate =FGR/GRC×100 using the fungal specific primer set: ITS1-F (5ʹ-CTTGGTCATTTAGAGGAAGTAA-3ʹ) and ITS4-R (5ʹ-TCCTCCGCTTATTGATATGC-3ʹ) as described by White et al [27]. PCR was performed in a final volume of 50 μL containing GoTaq (Promega, Madison, WI, USA) green master mix, 1 µL genomic DNA sample and 1 µL each primer (at a concentration of 0.5 mM) [15]. The PCR conditions were as the following: initial denaturation at 95°C for 5 min, followed by 40 cycles at 94°C for 1 min, 55°C for 1 min, 72°C for 1 min; final extension at 72°C for 10 min and holding at 4°C.…”

“…Microorganisms offer an enormous field of environment friendly options for mineralization of contaminants or their transformation into less harmful non-hazardous compounds. Recently, researchers have been focusing on the degradation of HMW-PAH which has resulted in the isolation of a number of indigenous microorganisms that can mineralize and grow on four or five-ringed PAHs as the sole carbon and energy source [14,15,32,33]. Enrichment technique is a way to obtain the promising indigenous microorganisms that could utilize PAHs as the sole carbon source [14].…”

“…In contrast, the identification methods by molecular genetics techniques are rapid, easy and more precise for microorganism's identification [15,16]. Strain HESHAM-1 was identified based on its morphological and microscopic examination as Fusarium sp.…”

Estimation of Bacterial Biodegradability of PAH in Khor Al-Zubair Channel, Southern Iraq

“…Therefore, the presence of six key enzymes coding genes, including both monooxygenase and dioxygenase in the ASU-06 strain of S. koreensis the existence of monooxygenase genes (alkB and alkB1) dioxygenase (naháč) and Catechol dioxygenase (C12O and C23O) genes was confirmed. Therefore, one possible reason may be that these genes are strong evidence between different conserved Gram-negative bacteria (Hesham et al, 2014). Figure 21 Crude oil 2.0% with Ochrobac.…”