Bacillus subtilis as heterologous host for the secretory production of the non-ribosomal cyclodepsipeptide enniatin

• Published in: Applied microbiology and biotechnology 2015-01, Vol.99 (2), p.681-691
• Main Authors: Zobel, Sophia, Kumpfmüller, Jana, Süssmuth, Roderich D, Schweder, Thomas
• Format: Article
• Language: English
• Subjects: Amino acids; Bacillus subtilis; Bacillus subtilis - genetics; Bacillus subtilis - metabolism; Bioactive compounds; bioactive properties; biochemical pathways; Biomedical and Life Sciences; bioprocess engineering; Biosynthesis; Biotechnological Products and Process Engineering; Biotechnology; Cloning; Cloning, Molecular; Culture Media; Depsipeptides - biosynthesis; E coli; Enzymes; Fungi; Gene expression; Genetic aspects; genetic background; Genetic engineering; Gram-positive bacteria; Health aspects; hosts; Identification and classification; Industrial Microbiology; Life Sciences; ligases; metabolic engineering; Metabolic Engineering - methods; Metabolism; Metabolites; Microbial Genetics and Genomics; Microbiology; multigene family; Observations; Peptide Synthases - genetics; Peptide Synthases - metabolism; Peptides; Plasmids; Plasmids - genetics; Promoter Regions, Genetic; Secondary metabolites; Streptococcus infections
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-014-6199-0

The heterologous expression of genes or gene clusters in microbial hosts, followed by metabolic engineering of biosynthetic pathways, is key to access industrially and pharmaceutically relevant compounds in an economically affordable and sustainable manner. Therefore, platforms need to be developed, which provide tools for the controlled synthesis of bioactive compounds. The Gram-positive bacterium Bacillus subtilis is a promising candidate for such applications, as it is generally regarded as a safe production host, its physiology is well investigated and a variety of tools is available for its genetic manipulation. Furthermore, this industrially relevant bacterium provides a high secretory potential not only for enzymes but also for primary and secondary metabolites. In this study, we present the first heterologous expression of an eukaryotic non-ribosomal peptide synthetase gene (esyn) coding for the biosynthesis of the small molecule enniatin in B. subtilis. Enniatin is a pharmaceutically used cyclodepsipeptide for treatment of topical bacterial and fungal infections. We generated various enniatin-producing B. subtilis strains, allowing for either single chromosomal or plasmid-based multi-copy expression of the esyn cluster under the control of an acetoin-inducible promoter system. Optimization of cultivation conditions, combined with modifications of the genetic background and multi-copy plasmid-based esyn expression, resulted in a secretory production of enniatin B. This work presents B. subtilis as a suitable host for the expression of heterologous eukaryotic non-ribosomal peptide synthetases (NRPS) clusters.