Enhanced Hydrocarbons Degradation in the Rhizosphere of Mangrove Plants by a HalophilicBacillus Subtilis SubtilisStrain

Abstract

Sulaibikhat Embayment is a severely contaminated coastline in the State of Kuwait. The contaminating pollutants include hydrocarbons, heavy metals, and suspended particles. The objective of this study is to assess the ability of mangroves planted in the Sulaibikhat Embayment to enhance hydrocarbons degradation by the activities of rhizospheric hydrocarbon degrading bacteria (HDB). Accordingly, samples were collected from the rhizosphere of selected mangrove plants and from sediments in the same location but away from mangrove marshes. The samples were analyzed chemically and microbiologically before being enriched with a mixture of hydrocarbon compounds (HC) to isolate HDB.A number of halophilic HDB were isolated from mangroves rhizosphere and the surrounding sediments such as Pseudomonas balearica, Microbacterium barkeri and Gordonia soli. On the other hand, Bacillus velezensis and Bacillus subtilis subtilis were both isolated only from mangroves rhizosphere. Among the isolated HDB, Bacillus subtilis subtilis was distinguished with its high degradation rates of the tested HC including poly aromatic hydrocarbons. According to our knowledge, this is the first Bacillus subtilis HC-degrading strain that was isolated from Kuwait Bay and from mangroves rhizosphere.

The abundant occurrence of hydrocarbon-utilizing bacteria in the phyllospheres of cultivated and wild plants in Kuwait

“…There is currently extensive information about hydrocarbonutilizing microorganisms in aquatic habitats (Adebusoye et al, 2007;Shemer and Linden, 2007;Radwan, 2008;Das and Chandran, 2011), terrestrial habitats (Radwan, 2008;Chikere et al, 2011;Erdogan and Karaca, 2011), plant leaves (Ilori et al, 2006), and rhizospheres (Barea et al, 2005;Radwan, 2009;Yateema and Al-Sharrahb, 2011), and their role in the bioremediation of oil-polluted environments (Leahy and Colwell, 1990;Radwan, 2008Radwan, , 2009Kumar et al, 2011). The unique property of these microorganisms, which makes them capable of degrading hydrocarbons, is their possession of oxygenase (also called hydroxylase) systems that catalyze the splitting of O 2 molecules into oxygen atoms, introducing the latter into aliphatic and aromatic hydrocarbons yielding the corresponding hydroxylated compounds.…”

Biodegradation of petroleum by bacteria isolated from fishes of Indian Ocean

“…The 16S rRNA (1450 bp amplicon size) sequencing characterization confirmed that isolates G3A and G4A showed 99% identity with genus Bacillus where as G3A was identical with Bacillus flexus and G4A was identical with Bacillus velezensis. Both bacteria were previously reported as oil degraders (Ren et al, 2012;Yateem et al, 2011). Species of the genus Bacillus are usually scattered in oil contaminated environments due to its low nutritive value (Cybulski et al, 2003).…”

Bacillus subtilis BR4 derived stigmatellin Y interferes Pqs‐PqsR mediated quorum sensing system of Pseudomonas aeruginosa

“…[18], Vibrio sp. [19], B. subtilis [20], Marinobacterium sp. [21], B. cereus [22], Bacillus oceanisediminis [23] have also been reported previously in the mangrove rhizospheric environment.…”