title: Substitution of the native srfA promoter by constitutive Pveg in two B. subtilis strains and evaluation of the effect on Surfactin production.
abstract: The genetic enhancement of Surfactin production increasingly gained attention in the last years, since relatively low product yields limit the industrial application of this biosurfactant. The natural quorum sensing regulation of the srfA operon (coding for the Surfactin synthetase) can reasonably be assumed to be the bottleneck of Surfactin synthesis. Therefore, the replacement of the naturally quorum sensing regulated, and herewith cell density dependent, promoter PsrfA against the Bacillus subtilis endogenous and constitutive promoter Pveg was hypothesized to generally enhance Surfactin yields. The markerless promoter replacement was conducted in the two B. subtilis Surfactin producer strains 3A38 and DSM 10(T). The promoter substitution led to an enhancement of Surfactin concentrations in the producer strain 3A38, initially producing only minor amounts of Surfactin (0.07g/L increased to 0.26g/L). In contrast, promoter exchange in B. subtilis DSM 10(T) (wild-type strain producing 0.62g/L Surfactin) did not achieve an enhancement of Surfactin concentrations (detrimental reduction to 0.04g/L). These findings implicate that Surfactin synthesis is differently regulated in minor and strong Surfactin producer strains. The hypothesized general enhancement of Surfactin yields after substitution of the native promoter was therefore not confirmed.
authors.affiliation: Institute of Process Engineering in Life Sciences, Section II: Technical Biology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany. Electronic address: judit.willenbacher@kit.edu.
authors.forename: Judit
authors.initials: J
authors.lastname: Willenbacher
authors.affiliation: Institute of Process Engineering in Life Sciences, Section II: Technical Biology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany. Electronic address: teresa.mohr@student.kit.edu.
authors.forename: Teresa
authors.initials: T
authors.lastname: Mohr
authors.affiliation: Institute of Food Science and Biotechnology (150), Section Bioprocess Engineering (150k), University of Hohenheim, Garbenstr. 25, 70599 Stuttgart, Germany. Electronic address: marius.henkel@uni-hohenheim.de.
authors.forename: Marius
authors.initials: M
authors.lastname: Henkel
authors.affiliation: Milner Centre for Evolution, Department of Biology & Biochemistry, University of Bath, Claverton Down, BA2 7AY Bath, United Kingdom. Electronic address: s.gebhard@bath.ac.uk.
authors.forename: Susanne
authors.initials: S
authors.lastname: Gebhard
authors.affiliation: Institute of Microbiology, General Microbiology, Technische Universität Dresden, Zellescher Weg 20b, 01062 Dresden, Germany. Electronic address: thorsten.mascher@tu-dresden.de.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Mascher
authors.affiliation: Institute of Process Engineering in Life Sciences, Section II: Technical Biology, Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 3, 76131 Karlsruhe, Germany. Electronic address: christoph.syldatk@kit.edu.
authors.forename: Christoph
authors.initials: C
authors.lastname: Syldatk
authors.affiliation: Institute of Food Science and Biotechnology (150), Section Bioprocess Engineering (150k), University of Hohenheim, Garbenstr. 25, 70599 Stuttgart, Germany. Electronic address: rudolf.hausmann@uni-hohenheim.de.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hausmann
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development*; D001426:Bacterial Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D055666:Lipopeptides / Q000096:biosynthesis*; D010453:Peptide Synthases / Q000235:genetics*; D010456:Peptides, Cyclic / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D053038:Quorum Sensing; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D055666:Lipopeptides; D010456:Peptides, Cyclic; D011994:Recombinant Proteins; C009365:surfactin peptide; D010453:Peptide Synthases; C069542:surfactin synthetase
keywords: Bacillus subtilis; Biosurfactant; Promoter exchange; Quorum sensing; Surfactin; srfA operon