Isolation and characterization of a novel biosurfactant produced by hydrocarbon-degrading bacteriumAlcanivorax dieseloleiB-5

Abstract

Aims: Our goal was to identify a novel biosurfactant produced by a marine oil‐degrading bacterium. Methods and Results: Biosurfactants were produced by Alcanivorax dieselolei strain B‐5T growing with diesel oil as the sole carbon and energy source. Culture supernatant was first extracted with chloroform/methanol (1 : 1, v/v), then further purified step by step with a normal phase silica gel column, a Sephadex LH20 gel column and a preparative thin layer plate. The main component was determined to be a lipopeptide; it was chemically characterized with nuclear magnetic resonance, liquid chromatography‐quadrupole ion‐trap mass spectrometry, amino acid analysis and GC–MS and was found to be a mixture of proline lipids. The monomers of the proline lipids were composed of a proline residue and a fatty acid (C14:0, C16:0 or C18:0). The critical micelle concentration of the mixed proline lipids was determined to be 40 mg l−1. Moreover, activity variations in ranges of pH, temperature and salinity were also detected and showed reasonable stability. Conclusions: Alcanivorax dieselolei B‐5 produced a novel linear lipoamino biosurfactant, characterized as a proline lipid. Significance and Impact of the Study: A proline lipid was characterized for the first time as a bacterial biosurfactant. This product has potential in both environmental and industrial applications.

Biofilm inhibition and antimicrobial action of lipopeptide biosurfactant produced by heavy metal tolerant strain Bacillus cereus NK1

“…Hence the biosurfactant was structurally very stable and retained its surfactant activity even at the extremes of pH, temperature and NaCl concentration. Similar results were also reported by Qiao et al [50] for the biosurfactant obtained from Alcanivorax species. …”

Hydrocarbon-Degrading Bacteria Exhibit a Species-Specific Response to Dispersed Oil while Moderating Ecotoxicity

“…Alcanivorax dieselolei produces a lipoprotein (proline lipids) when grown on hexadecane, and this strain reduces the surface tension of water to 29.6 to 32.8 mN/m. This strain did not produce detectable glycolipids (61). The Alcanivorax strain used in this study (P2S70) is not closely related to either A. dieselolei or A. borkumensis (average nucleotide identity [ANI] of 80.2% and 81.6%, respectively), and we cannot speculate on the biosurfactant produced by this strain at this time.…”

Hydrocarbonoclastic Alcanivorax Isolates Exhibit Different Physiological and Expression Responses to n-dodecane

“…As many other hydrocarbonoclastic bacteria, they are able to produce biosurfactants to facilitate their access to alkanes. A. dieselolei produces a proline lipid active in a wide range of pH and temperature (Qiao and Shao, 2010), while A. borkumensis produces many different glycolipid biosurfactants (Abraham et al, 1998; Yakimov et al, 1998). Furthermore, since it has been proved the absence of the Alcanivorax genus in deep sea environments contaminated by hydrocarbons (Hazen et al, 2010; Bælum et al, 2012), the capability of this genus to adapt and survive at high hydrostatic pressure has been recently investigated in A. borkumensis SK2 and A. dieselolei KS 293, highlighting different strategies to cope with this environmental stressor (Scoma et al, 2016a,b).…”