Production and Properties of a Surface-Active Lipopeptide Produced by a New Marine Brevibacterium luteolum Strain

Abstract

Microbial-derived surfactants are molecules of great interest due to their environmentally friendly nature and low toxicity; however, their production cost is not competitive when compared to synthetics. Marine microorganisms are exposed to extremes of pressure, temperature, and salinity; hence, they can produce stable compounds under such conditions that are useful for industrial applications. A screening program to select marine bacteria able to produce biosurfactant using low-cost substrates (mineral oil, sucrose, soybean oil, and glycerol) was conducted. The selected bacterial strain showed potential to synthesize biosurfactants using mineral oil as carbon source and was identified as Brevibacterium luteolum. The surface-active compound reduced the surface tension of water to 27 mN m(-1) and the interfacial tension (water/hexadecane) to 0.84 mN m(-1) and showed a critical micelle concentration of 40 mg L(-1). The biosurfactant was stable over a range of temperature, pH, and salt concentration and the emulsification index (E24) with different hydrocarbons ranging from 60 to 79 %. Structural characterization revealed that the biosurfactant has a lipopeptide nature. Sand washing removed 83 % of crude oil demonstrating the potential of the biosurfactants (BS) for bioremediation purposes. The new marine B. luteolum strain showed potential to produce high surface-active and stable molecule using a low-cost substrate.

Marinobacter sp. from marine sediments produce highly stable surface-active agents for combatting marine oil spills

“…However, in that case the assay was performed under slightly different conditions, i.e. evaluation of the surface activity was performed at room temperature after incubating the biosurfactants at 4 °C for 24 h [ 41 ], while in our case the emulsions were let to form at 4 °C and using cold culture supernatant and solvents, resulting in stabilizing the formed emulsion. The fact that the produced bioemulsifiers were active at low temperature and high salt concentration is an optimal trait to be considered when application under seawater conditions are targeted.…”

“…These values are higher compared to those reported for chemical biosurfactants like Tween 80 (110 mg/l) [ 39 ] or Triton X-100 (150 mg/l) and to other marine bacteria such as Streptomyces sp. (36 mg/l) [ 49 ], Brevibacterium luteolum (40 mg/l) [ 41 ] and Halomonas sp. MB-30 (250 mg/l) [ 50 ].…”

The Impact of Biosurfactants on Microbial Cell Properties Leading to Hydrocarbon Bioavailability Increase

“…Kowalewski et al [137] found that a reduction in interfacial tension in an oil-water-bacteria system is an important feature in enhanced oil recovery, but it might be caused by bacteria themselves. It is worth mentioning, that the advantages of biosurfactants as environmental-friendly compounds with high surface-active properties allow also their use in soil-washing/flushing techniques, which are aimed at organic pollutants removal from contaminated soils [138], however without biodegradation processes [30,109,[139][140][141].…”

Therapeutic cyclic lipopeptides mining from microbes: latest strides and hurdles

“…Marine Brevibacterium luteolum strain produced a lipopeptide that possesses bioremediation ability. Reduction of surface tension was detected to be the mechanism (Vilela et al 2014). Pseudomonas sp.…”