title: Biosurfactant production by Pseudomonas strains isolated from floral nectar.
abstract: OBJECTIVE
  To screen and identify biosurfactant-producing Pseudomonas strains isolated from floral nectar; to characterize the produced biosurfactants; and to investigate the effect of different carbon sources on biosurfactant production.
  
  
  RESULTS
  Four of eight nectar Pseudomonas isolates were found to produce biosurfactants. Phylogenetic analysis based on three housekeeping genes (16S rRNA gene, rpoB and gyrB) classified the isolates into two groups, including one group closely related to Pseudomonas fluorescens and another group closely related to Pseudomonas fragi and Pseudomonas jessenii. Although our nectar pseudomonads were able to grow on a variety of water-soluble and water-immiscible carbon sources, surface active agents were only produced when using vegetable oil as sole carbon source, including olive oil, sunflower oil or waste frying sunflower oil. Structural characterization based on thin layer chromatography (TLC) and ultra high performance liquid chromatography-accurate mass mass spectrometry (UHPLC-amMS) revealed that biosurfactant activity was most probably due to the production of fatty acids (C16:0; C18:0; C18:1 and C18:2), and mono- and diglycerides thereof.
  
  
  CONCLUSIONS
  Four biosurfactant-producing nectar pseudomonads were identified. The active compounds were identified as fatty acids (C16:0; C18:0; C18:1 and C18:2), and mono- and diglycerides thereof, produced by hydrolysis of triglycerides of the feedstock.
  
  
  CONCLUSIONS
  Studies on biosurfactant-producing micro-organisms have mainly focused on microbes isolated from soils and aquatic environments. Here, for the first time, nectar environments were screened as a novel source for biosurfactant producers. As nectars represent harsh environments with high osmotic pressure and varying pH levels, further screening of nectar habitats for biosurfactant-producing microbes may lead to the discovery of novel biosurfactants with broad tolerance towards different environmental conditions.
authors: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, Sint-Katelijne Waver, Belgium.
authors: Z
authors: Z
authors: Ben Belgacem
authors: Flemish Institute for Technological Research (VITO), Business Unit Separation and Conversion Technology (SCT), Mol, Belgium.
authors: S
authors: S
authors: Bijttebier
authors: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, Sint-Katelijne Waver, Belgium.
authors: C
authors: C
authors: Verreth
authors: Flemish Institute for Technological Research (VITO), Business Unit Separation and Conversion Technology (SCT), Mol, Belgium.
authors: S
authors: S
authors: Voorspoels
authors: Laboratory of Enzyme, Fermentation, and Brewing Technology, Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus KaHo Sint-Lieven, Ghent, Belgium.
authors: I
authors: I
authors: Van de Voorde
authors: Laboratory of Enzyme, Fermentation, and Brewing Technology, Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus KaHo Sint-Lieven, Ghent, Belgium.
authors: G
authors: G
authors: Aerts
authors: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, Sint-Katelijne Waver, Belgium.
authors: K A
authors: KA
authors: Willems
authors: Division of Plant Ecology and Systematics, Biology Department, KU Leuven, Leuven, Belgium.
authors: H
authors: H
authors: Jacquemyn
authors: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, Sint-Katelijne Waver, Belgium.
authors: S
authors: S
authors: Ruyters
authors: Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, Sint-Katelijne Waver, Belgium.
authors: B
authors: B
authors: Lievens
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D035264:Flowers / Q000737:chemistry / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D057048:Plant Nectar / Q000737:chemistry*; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D057048:Plant Nectar; D012336:RNA, Ribosomal, 16S; D013501:Surface-Active Agents
keywords: Pseudomonas sp; biosurfactant; fatty acids; nectar; surface tension