Biosurfactant production by Pseudomonas aeruginosa DSVP20 isolated from petroleum hydrocarbon-contaminated soil and its physicochemical characterization

Abstract

Among 348 microbial strains isolated from petroleum hydrocarbon-contaminated soil, five were selected for their ability to produce biosurfactant based on battery of screening assay including hemolytic activity, surface tension reduction, drop collapse assay, emulsification activity, and cell surface hydrophobicity studies. Of these, bacterial isolate DSVP20 was identified as Pseudomonas aeruginosa (NCBI GenBank accession no. GQ865644) based on biochemical characterization and the 16S rDNA analysis, and it was found to be a potential candidate for biosurfactant production. Maximum biosurfactant production recorded by P. aeruginosa DSVP20 was 6.7 g/l after 72 h at 150 rpm and at a temperature of 30 °C. Chromatographic analysis and high-performance liquid chromatography-mass spectrometry (HPLC-MS) revealed that it was a glycolipid in nature which was further confirmed by nuclear magnetic resonance (NMR) spectroscopy. Bioremediation studies using purified biosurfactant showed that P. aeruginosa DSVP20 has the ability to degrade eicosane (97%), pristane (75%), and fluoranthene (47%) when studied at different time intervals for a total of 7 days. The results of this study showed that the P. aeruginosa DSVP20 and/or biosurfactant produced by this isolate have the potential role in bioremediation of petroleum hydrocarbon-contaminated soil.

Structural and Physicochemical Characterization of Rhamnolipids produced by Pseudomonas aeruginosa P6

“…In 13 C NMR, signals between 10.0 and 40.0 ppm were ascribed to aliphatic groups; between 68 and 80 ppm were due to carbon atoms in rhamnose moiety; and signals at 170–175 ppm were attributed to the carbonyl groups (Silva et al 2014 ). Taken together, 1 H and 13 C NMR spectra obtained proved the presence of RLs in the mixture and the spectra coincided with previously published RLs spectra for both 1 H NMR (Charles Oluwaseun et al 2017 ; Raza et al 2009 ; Sharma et al 2015 ) and 13 C NMR (Charles Oluwaseun et al 2017 ; Silva et al 2014 ; Twigg et al 2018 ). Since the precise RLs structure was unachievable using NMR, further characterization using HPLC-MS was carried out.…”

“…1 . Data from previous studies was used to assign the NMR signals as shown in Table 1 (Nicolo et al 2017 ; Sharma et al 2015 ).…”

Microbial production of rhamnolipids: opportunities, challenges and strategies

“…For example, economic carbon sources such as wastes and renewable substrates [ 3 ] can be used to replace some conventional substrates. These include mannitol [ 33 ], glucose, glycerol, n -paraffin [ 34 , 35 ], n -alkane, polycyclic aromatic hydrocarbons [ 36 ] and vegetable oils [ 37 ]. The diversity of renewable resources that can be used as carbon and nitrogen sources for rhamnolipid fermentation with reduced substrate cost are discussed in detail in several recent reviews [ 3 , 38 – 40 ].…”

Isolation, characterization, and optimization of biosurfactant production by an oil-degrading Acinetobacter junii B6 isolated from an Iranian oil excavation site

“…Biosurfactant producers mostly exist in oil contaminated soils, where they are able to facilitate the uptake of hydrocarbons through the formation and release of surface active molecules (Chen et al, 2012). There are many reports about the isolation of Bacillus and Pseudomonas species as biosurfactant producers from oilcontaminated areas (Chandankere et al, 2013;Sharma et al, 2015). However, such ability in the genus of Acinetobacter has been seldom described.…”