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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Microbiotechnology
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1459112
This article is part of the Research Topic Biosurfactants - Next Generation Biomolecules for Enhanced Biodegradation of Organic Pollutants, Volume II View all 5 articles

Molecular Identification of Rhamnolipids Produced by Pseudomonas oryzihabitans during Biodegradation of Crude Oil

Provisionally accepted
Saman Hosseini Saman Hosseini 1Rouhallah Sharifi Rouhallah Sharifi 1*Alireza Habibi Alireza Habibi 1Qurban Ali Qurban Ali 2
  • 1 Razi University, Kermanshah, Iran
  • 2 United Arab Emirates University, Al-Ain, Abu Dhabi, United Arab Emirates

The final, formatted version of the article will be published soon.

    The ability to produce biosurfactants plays a meaningful role in the bioavailability of crude oil hydrocarbons and the bioremediation efficiency of crude oil-degrading bacteria. This study aimed to characterize the produced biosurfactants by Pseudomonas oryzihabitans during the biodegradation of crude oil hydrocarbons.The biosurfactants were isolated and then characterized by Fourier transform infrared (FTIR), liquid chromatography-mass-spectrometry (LC-MS), and nuclear magnetic resonance spectroscopy (NMR) analyses.The FTIR results revealed the existence of hydroxyl, carboxyl, and methoxyl groups in the isolated biosurfactants. Also, the LC-MS analysis demonstrated a main di-rhamnolipid (lrhamnopyranosyll-rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate, Rha-Rha-C10-C10) along with a mono-rhamnolipid (l-rhamnopyranosyl-b-hydroxydecanoylb-hydroxydecanoate, Rha-C10-C10). In agreement with these findings, the NMR analysis confirmed the aromatic, carboxylic, methyl, sulfate moieties, and hexose sugar in the biosurfactants. The emulsion capacity of the biosurfactants decreased the surface tension of the aqueous system from 73.4 mN m -1 to around 33 mN m -1 at 200 mg L -1 as the critical micelle concentration. The emulsification capacity of the biosurfactants in the formation of a stable microemulsion for the diesel-water system at a wide range of pH (2-12), temperature (0-80ᵒC), and salinity (2-20 g L -1 of NaCl) showed their potential use in oil recovery and bioremediation through the use of microbial enhancement.Discussion: This work showed the ability of Pseudomonas oryzihabitans NC392 cells to produce rhamnolipid molecules during the biodegradation process of crude oil hydrocarbons. These biosurfactants have potential in bioremediation studies as eco-friendly and biodegradable products, and their stability makes them optimal for areas with extreme conditions.

    Keywords: bioremediation, Biosurfactant production, Critical micelle concentration, Emulsification capacity, Hydrocarbon-degrading bacteria, Rhamnolipid

    Received: 03 Jul 2024; Accepted: 07 Aug 2024.

    Copyright: © 2024 Hosseini, Sharifi, Habibi and Ali. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Rouhallah Sharifi, Razi University, Kermanshah, Iran

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.