Microbial synthesis of terpenoids for human nutrition - an emerging field with high business potential.

Because of their complicated biosynthesis and hydrophobic nature, fermentative production of terpenoids did not play a significant role on a commercial scale until a few years ago. Driven by technological progress in metabolic engineering and process biotechnology, terpene-based food ingredients such as flavors, sweeteners, and vitamins produced by fermentation have now become viable and commercially competitive options. In recent years, several companies have developed microbial platforms for commercial terpene production.

Antibacterial Marinopyrroles and Pseudilins Act as Protonophores.

Elucidating the mechanism of action (MoA) of antibacterial natural products is crucial to evaluating their potential as novel antibiotics. Marinopyrroles, pentachloropseudilin, and pentabromopseudilin are densely halogenated, hybrid pyrrole-phenol natural products with potent activity against Gram-positive bacterial pathogens like . However, the exact way they exert this antibacterial activity has not been established.

Detoxification of monoterpenes by a family of plant glycosyltransferases.

Plant monoterpenes are challenging compounds, since they often act as solvents, and thus have both phytotoxic and antimicrobial properties. In this study an approach is developed to identify and characterize enzymes that can detoxify monoterpenoids, and thus would protect both plants and microbial production systems from these compounds. Plants respond to the presence of monoterpenes by expressing glycosyltransferases (UGTs), which conjugate the monoterpenoids into glycosides.

Identification of Fungal Limonene-3-Hydroxylase for Biotechnological Menthol Production.

More than 30,000 tons of menthol are produced every year as a flavor and fragrance compound or as a medical component. So far, only extraction from plant material and chemical synthesis are possible. An alternative approach for menthol production could be a biotechnological-chemical process with ideally only two conversion steps, starting from (+)-limonene, which is a side product of the citrus processing industry.

Investigation of monoterpenoid resistance mechanisms in Pseudomonas putida and their consequences for biotransformations.

Monoterpenoids are widely used in industrial applications, e.g. as active ingredients in pharmaceuticals, in flavor and fragrance compositions, and in agriculture.

Microbial Cell Factories for the Production of Terpenoid Flavor and Fragrance Compounds.

Terpenoid flavor and fragrance compounds are of high interest to the aroma industry. Microbial production offers an alternative sustainable access to the desired terpenoids independent of natural sources. Genetically engineered microorganisms can be used to synthesize terpenoids from cheap and renewable resources.

Investigation of plasmid-induced growth defect in Pseudomonas putida.

Genetic engineering in bacteria mainly relies on the use of plasmids. But despite their pervasive use for physiological studies as well as for the design and optimization of industrially used production strains, only limited information about plasmid induced growth defects is available for different replicons and organisms. Here, we present the identification and characterization of such a phenomenon for Pseudomonas putida transformants carrying the pBBR1-derived plasmid pMiS1.

A novel and widespread class of ketosynthase is responsible for the head-to-head condensation of two acyl moieties in bacterial pyrone biosynthesis.

The biosynthesis of photopyrones, novel quorum sensing signals in Photorhabdus, has been studied by heterologous expression of the photopyrone synthase PpyS catalyzing the head-to-head condensation of two acyl moieties. The biochemical mechanism of pyrone formation has been investigated by amino acid exchange and bioinformatic analysis. Additionally, the evolutionary origin of PpyS has been studied by phylogenetic analyses also revealing homologous enzymes in Pseudomonas sp.