Elucidation and Optimization of the EDDS Biosynthesis in
Amycolatopsis japonicum

The complexing agent ethylenediamine-disuccinic acid (EDDS) is a structural isomer of ethylenediamine-tetra-acetate (EDTA). EDTA is widely used in paper, textile, and laundry industry, but also in cosmetics, food, and as medical additive. Due to its poor degradability, EDTA might become an environmental hazard. Its isomer [S,S]-EDDS has similar chelating properties as EDTA. However, in contrast to EDTA the isomer [S,S]-EDDS is easily biodegradable. Therefore, a chemical process to produce [S,S]-EDDS has already been established. Nevertheless we are interested in developing a biotechnological way to economically produce [S,S]-EDDS as an alternative for chemically synthesized [S,S]-EDDS. A biotechnological large scale production of [S,S]-EDDS was not possible until now, because already 2 μM zinc, a concentration occurring ubiquitously in standard media, inhibits the synthesis of [S,S]-EDDS. We developed a process to synthesize [S,S]-EDDS biotechnologically using an optimized Amycolatopsis japonicum strain, that produces [S,S]-EDDS in the presence of zinc and in rather cheap, complex media. The aim of this project is the elucidation of EDDS biosynthetic steps and the further yield optimization.

Project of Simone Edenhart

SYSTERACT
Systematic Rebuilding of Actinomycetes for Natural Product Formation

Actinomycetes are an important reservoir for novel bioactive compounds. In our group we evaluate the capacity of actionmycetes strains to produce secondary metabolites using different genome mining approaches and analysis software. The most of the identified clusters are “silent” under standard laboratory conditions. Hence, the activation and enhancement of “silent” pathways is of high interest. Heterologous expression has proved very effective for inducing metabolite production, for different classes of secondary metabolites. In the European ERASysAPP-project we aim to identify potential bottlenecks in metabolic precursor pools towards secondary metabolite production and generate an improved heterologous strain for gene cluster expression and, efficient production of antibiotic compounds.

Project of Dumitrita Iftime

Natural products from Streptomycetes are an important source of novel antibiotics to fight antibiotic resistant bacteria. Although these compounds often exhibit a great efficacy when tested against specific targets, they can display characteristics that require enhancement, i.e. production yield, solubility, bioavailability, human toxicity, stability or metabolism. To increase antibiotics production yield and generate improved derivatives by mutasynthesis, the biosynthetic gene clusters responsible for their production need to be identified and the biosynthetic pathways elucidated.

The aim of this project is the identification and characterization of Streptomycetes antibiotic gene clusters, and the rational design of antibiotics analogues by mutasynthesis.

This DZIF-project is a corporate project together with Prof. Heike Brötz Österhelt (Microbial Bioactive Compounds, IMIT, University of Tübingen) and Yvonne Mast (Microbiology/Biotechnology, IMIT, University of Tübingen).

Project of Helena Sales Ortells

The investigation of self-resistance mechanisms revealed that resistance is not only based on a single determinant but on the synergistic action of different factors. The synthesis of modified PG is a common feature, which we could identify in antibiotic producers as Amycolatopsis balhimycina and Microbispora ATCC PTA-5024.

In this SFB-project we investigate the alternative metabolic pathways that are used to synthesize glycopeptide resistant peptidoglycan precursors. In particular, we determine the relevance of unusual peptidoglycan cross-linking, which are catalyzed by L,D-transpeptidases, for the resistance.

Project of Sandra Unsleber

ACTIVATION OF SILENT SECONDARY METABOLITE CLUSTERS BY VARIOUS REGULATORY PROTEINS IN ACTINOMYCETES

Actinomycetes are producers of many secondary metabolites with various applications as medical, agricultural and industrial. The biosynthesis of secondary metabolites is encoded in their genomes and is usually organized in clusters. The continuously increasing genome sequencing data have revealed the presence of numerous clusters in Actinobacteria, which might encode novel secondary metabolites with interesting biological activities. However, utilization of this hidden potential has been hindered by the observation that many of these gene clusters remain „silent“ (or cryptic or poorly expressed) under laboratory conditions.

In our approach we are focusing on the activation of silent secondary metabolite clusters by using a set of regulatory proteins from different Streptomyces strains.

Project of Erik Mingyar