Abstract
Bacterial bio-surfactants have a wide range of biological functions and biotechnological applications. Previous analyses had suggested a limit to their reduction of aqueous liquid surface tensions (gMin), and here we confirm this in an analysis of 25 Pseudomonas spp. strains isolated from soil which produce high-strength surfactants that reduce surface tensions to 25.2 ± 0.1 – 26.5 ± 0.2 mN.m-1 (the surface tension of sterile growth medium and pure water was 52.9 ± 0.4 mN.m-1 and 72.1 ± 1.2 mN.m-1, respectively). Comparisons of culture supernatants produced using different growth media and semi-purified samples indicate that the limit of 24.2 – 24.7 mN.m-1 is not greatly influenced by culture conditions, pH or NaCl concentrations. We have used foam, emulsion and oil-displacement behavioural assays as a simple and cost-effective proxy for in-depth biochemical characterisation, and these suggest there is significant structural diversity amongst these surfactants which may reflect different biological functions and offer new biotechnological opportunities. Finally, we obtained a draft genome for the strain producing the highest-strength surfactant, and identified a cluster of non-ribosomal protein synthase genes which may produce a cyclic-lipopeptide (CLP)–like surfactant. Further investigation of this group of related bacteria recovered from the same site will allow a better understanding of the significance of the great variety of surfactants produced by bacterial communities found in soil and elsewhere.
Original language | English |
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Article number | fny008 |
Number of pages | 7 |
Journal | FEMS Microbiology Letters |
Volume | 365 |
Issue number | 4 |
Early online date | 16 Jan 2018 |
DOIs | |
Publication status | Published - 1 Feb 2018 |
Keywords
- Pseudomonas
- Surfactant
- Limit to liquid surface activity
- Cyclic lipopeptide
- Non-ribosomal protein synthase
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Student Theses
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Bioprospecting surfactants produced by Pseudomonas spp. isolated from soil for potential application in biotechnology
Author: Kabir, K., 18 Aug 2017Supervisor: Spiers, A. J. (Supervisor) & Deeni, Y. (Supervisor)
Student thesis: Doctoral Thesis
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