Relationship between temperature, branched fatty acid synthesis and mycosubtilin isoform production in Bacillus subtilis.

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Biofilm formation is determinant in tomato rhizosphere colonization by Bacillus velezensis FZB42

National audienceIn this work, the behavior in tomato rhizosphere of Bacillus velezensis FZB42 was analyzed taking into account the surfactin production, the use of tomato roots exudate as substrates, and the biofilm formation. B. velezensis FZB42 and B. amyloliquefaciens S499 have a similar capability to colonize tomato rhizosphere. Little difference in this colonization was observed with surfactin non producing B. velezensis FZB42 mutant strains. B. velezensis is able to grow in the presence of root exudate and used preferentially sucrose, maltose, glutamic, and malic acids as carbon sources. A mutant enable to produce exopolysaccharide (EPS-) was constructed to demonstrate the main importance of biofilm formation on rhizosphere colonization. This mutant had completely lost its ability to form biofilm whatever the substrate present in the culture medium and was unable to efficiently colonize tomato rhizosphere

Synthetic Engineering of Bacillus subtilis to Overproduce Lipopeptide Biosurfactants

International audienceSynthetic engineering of bacteria aims at genetically modifying existing strains in order to turn them into efficient factories for target metabolites, such as biofuels or bioproducts. Thereby, computational models are used to predict the effects of modifications and by this to enable a more directed search for promising modification strategies. In this work, we first analyzed the limiting factors of the biosynthesis, by Bacillus subtilis 168, of surfactin which is considered as one of the best biosurfactants known so far. This lipopeptidic compound is synthesized by an assembly line machinery constituted of four NonRibosomal Peptide Synthetases (NRPS) encoded by the same operon. Three potential bottlenecks were identified: the intracellular level of synthetases, the transformation of apo-form of synthetases in holo-form by a phosphopantetheinyl transferase and the intracellular concentration of surfactin precursors. First, a foreign Bacillus gene encoding an efficient phosphopantetheinyl transferase (Sfp+) was introduced into the chromosome of B. subtilis 168 sfp0. Then, the surfactin operon being regulated by a complex mechanism induced by quorum-sensing, its promoter was replaced by another promoter which led to a constitutive production of surfactin. For the third limiting factor, two strategies were performed. On one side, a knock-out of genes involved in the biosynthesis of another NRPS complex was done to limit the competition for precursors between the production of this compound and the biosynthesis of surfactin. On the other side, a new computational modelling approach based on abstract interpretation and constraint solving was developed to predict genetic modification strategies for the increase of NRPS precursors biosynthesis

High-level biosynthesis of the anteiso-C(17) isoform of the antibiotic mycosubtilin in Bacillus subtilis and characterization of its candidacidal activity.

High-level production (880 mg liter(-1)) and isolation of the anteiso-C(17) isoform of the lipopeptide mycosubtilin produced by a genetically engineered Bacillus subtilis strain are reported. Antifungal activity of this isoform, as determined via culture and fluorometric and cell leakage assays, suggests its potential therapeutic use as an antifungal agent, in particular against Candida spp.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Biosurfactants produit par une nouvelle souche de Bacillus subtilis, composition les comprenant, procédé d'obtention et application

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Composition et méthode de production de biosurfactants de Bacillus

Brevet délivré et transféré à la société LIPOFABRIK. Licence active.Biosurfactants produced by a strain of Bacillus sp and to uses thereof . A composition comprising the biosurfactants , and a method for producing the biosurfactants . A method for obtaining a biosurfactant , and a device for implementing the method . The production of biopesticides or biosurfactantsfor the phytosanitary industry , and in the fields of the food , cosmetics pharmaceutical and oil industries and the environment

Temperature dependence of mycosubtilin homologue production in Bacillus subtilis ATCC6633.

Bacillus subtilis ATCC6633 produces mycosubtilin, a non-ribosomally synthesized lipopeptide of the iturin family which presents antagonistic activities toward various phytopathogens. Different homologues with fatty acid moiety varying from C15 to C17 are usually co-produced, with their biological activities increasing with the number of carbons in the fatty acid chain. In the present report, we highlight that growth temperature modulates both the extent of mycosubtilin production and the relative abundance of the different homologues. A 30-fold increase in mycosubtilin production was observed when the temperature was decreased from 37 degrees C to 25 degrees C for both strain ATCC6633 and its derivative BBG100, a constitutive mycosubtilin overproducer. However, no significant difference in either the expression of the mycosubtilin synthetase encoding genes or in the intracellular synthetase concentration could be found, suggesting that the observed phenotype originated from a higher mycosubtilin synthetase turnover at lower temperature. We also point out that lower growth temperature leads to an increased proportion of odd-numbered fatty acid homologues as a consequence of de novo synthesis of C17 anteiso fatty acid following cell adaptation to low temperatures.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Cellular engineering of Bacillus subtilis to enhance the biosynthesis of highly active anti fungal lipopeptides

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