High Versatility of IPP and DMAPP Methyltransferases Enables Synthesis of C , C and C Terpenoid Building Blocks.

The natural substance class of terpenoids covers an extremely wide range of different structures, although their building block repertoire is limited to the C compounds DMAPP and IPP. This study aims at the characterization of methyltransferases (MTases) that modify these terpene precursors and the demonstration of their suitability for biotechnological purposes. All seven enzymes tested accepted IPP as substrate and altogether five C compounds and six C compounds were formed within the reactions.

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.

Investigation of fatty aldehyde and alcohol synthesis from fatty acids by αDox- or CAR-expressing Escherichia coli.

Fatty aldehydes are among the most important flavor and fragrance compounds. Most biotechnological production approaches make use of the one step conversion of fatty acids from renewable sources by the enzymes α-dioxygenase (αDox) or carboxylic acid reductase (CAR). Their reaction mechanisms and cofactor dependencies are very different.

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.

Efficient hydroxylation of 1,8-cineole with monoterpenoid-resistant recombinant Pseudomonas putida GS1.

In this work, monoterpenoid hydroxylation with Pseudomonas putida GS1 and KT2440 were investigated as host strains, and the cytochrome P450 monooxygenase CYP176A1 (P450cin) and its native redox partner cindoxin (CinC) from Citrobacter braakii were introduced in P. putida to catalyze the stereoselective hydroxylation of 1,8-cineole to (1R)-6β-hydroxy-1,8-cineole. Growth experiments in the presence of 1,8-cineole confirmed pseudomonads' superior resilience compared to E.

Bioprocess engineering for microbial synthesis and conversion of isoprenoids.

Isoprenoids represent a natural product class essential to living organisms. Moreover, industrially relevant isoprenoid molecules cover a wide range of products such as pharmaceuticals, flavors and fragrances, or even biofuels. Their often complex structure makes chemical synthesis a difficult and expensive task and extraction from natural sources is typically low yielding.

De novo production of the monoterpenoid geranic acid by metabolically engineered Pseudomonas putida.

Background: Production of monoterpenoids as valuable chemicals using recombinant microbes is a growing field of interest. Unfortunately, antimicrobial activity of most monoterpenoids hampers a wide application of microorganisms for their production. Strains of Pseudomonas putida, a fast growing and metabolically versatile bacterium, often show an outstanding high tolerance towards organic solvents and other toxic compounds.

Multiple improvement of astaxanthin biosynthesis in Xanthophyllomyces dendrorhous by a combination of conventional mutagenesis and metabolic pathway engineering.

Xanthophyllomyces dendrorhous (Phaffia rhodozyma) is the only yeast or fungus that synthesizes the commercially attractive carotenoid astaxanthin. For a suitable bioprocess, the wild type has to be modified for increasing biomass content. To achieve this, a two step strategy has been followed.

Biotechnological production of astaxanthin with Phaffia rhodozyma/Xanthophyllomyces dendrorhous.

The oxygenated β-carotene derivative astaxanthin exhibits outstanding colouring, antioxidative and health-promoting properties and is mainly found in the marine environment. To satisfy the growing demand for this ketocarotenoid in the feed, food and cosmetics industries, there are strong efforts to develop economically viable bioprocesses alternative to the current chemical synthesis. However, up to now, natural astaxanthin from Haematococcus pluvialis, Phaffia rhodozyma or Paracoccus carotinifaciens has not been cost competitive with chemically synthesized astaxanthin, thus only serving niche applications.

P450(BM-3)-catalyzed whole-cell biotransformation of alpha-pinene with recombinant Escherichia coli in an aqueous-organic two-phase system.

A recombinant Escherichia coli BL21 (DE3) strain overexpressing a variant of P450(BM-3) (V26T/R47F/A74G/F87V/L188K; abbreviated: BL21 (P450(BM-3) QM)) oxyfunctionalizes the bicyclic monoterpene alpha-pinene to alpha-pinene oxide, verbenol, and myrtenol. To address the low water solubility and the toxicity of terpenoids, an aqueous-organic two-phase bioprocess was developed. Diisononyl phthalate was selected as a biocompatible organic carrier solvent capable of masking the toxic effects mediated by alpha-pinene and of efficiently extracting the products enabling scale-up to the bioreactor.

Improvement of P450(BM-3) whole-cell biocatalysis by integrating heterologous cofactor regeneration combining glucose facilitator and dehydrogenase in E. coli.

Escherichia coli BL21, expressing a quintuple mutant of P450(BM-3), oxyfunctionalizes alpha-pinene in an NADPH-dependent reaction to alpha-pinene oxide, verbenol, and myrtenol. We optimized the whole-cell biocatalyst by integrating a recombinant intracellular NADPH regeneration system through co-expression of a glucose facilitator from Zymomonas mobilis for uptake of unphosphorylated glucose and a NADP(+)-dependent glucose dehydrogenase from Bacillus megaterium that oxidizes glucose to gluconolactone. The engineered strain showed a nine times higher initial alpha-pinene oxide formation rate corresponding to a sixfold higher yield of 20 mg g(-1) cell dry weight after 1.