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.

The use of proton transfer reaction mass spectrometry for high throughput screening of terpene synthases.

In this work, we introduce the application of proton transfer reaction mass spectrometry (PTR-MS) for the selection of improved terpene synthase mutants. In comparison with gas chromatography mass spectrometry (GC-MS)-based methods, PTR-MS could offer advantages by reduction of sample preparation steps and analysis time. The method we propose here allows for minimal sample preparation and analysis time and provides a promising platform for the high throughput screening (HTS) of large enzyme mutant libraries.

Effect of Root Storage and Forcing on the Carbohydrate and Secondary Metabolite Composition of Belgian Endive ( L. Var. ).

Belgian endive is grown in a two-step cultivation process that involves growing of the plants in the field, cold storage of the taproots, and a second growth period in dark conditions called forcing to yield the witloof heads. In this study, the changes in the carbohydrate content and the secondary metabolite composition were studied in different tissues of Belgian endive during the cultivation process. Belgian endive heads contain between 336-388 mg/g DW of total soluble carbohydrates, predominantly fructose and glucose.

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.

Effect of food processing on antioxidants, their bioavailability and potential relevance to human health.

It has long been recognized that the antioxidants present in fresh plant materials may be very different to those we ingest our foods. This is often due to the use of food processing strategies involving thermal/non-thermal treatments. Current research mostly focuses on determining what is present in vegetative starting materials; how this is altered during processing; how this influences activity in the gut and following uptake into bloodstream; and which physiological effects this may have on human body.

Inactivation of the germacrene A synthase genes by CRISPR/Cas9 eliminates the biosynthesis of sesquiterpene lactones in Cichorium intybus L.

Chicory (Cichorium intybus var. sativum) is an industrial crop species cultivated for the production of a fructose polymer inulin, which is used as a low-calorie sweetener and prebiotic. Besides, inulin chicory taproots also accumulate sesquiterpene lactones (STLs).

Integrating structure-based machine learning and co-evolution to investigate specificity in plant sesquiterpene synthases.

Sesquiterpene synthases (STSs) catalyze the formation of a large class of plant volatiles called sesquiterpenes. While thousands of putative STS sequences from diverse plant species are available, only a small number of them have been functionally characterized. Sequence identity-based screening for desired enzymes, often used in biotechnological applications, is difficult to apply here as STS sequence similarity is strongly affected by species.

Several geranylgeranyl diphosphate synthase isoforms supply metabolic substrates for carotenoid biosynthesis in tomato.

Geranylgeranyl diphosphate (GGPP) produced by GGPP synthase (GGPPS) serves as a precursor for many plastidial isoprenoids, including carotenoids. Phytoene synthase (PSY) converts GGPP into phytoene, the first committed intermediate of the carotenoid pathway. Here we used biochemical, molecular, and genetic tools to characterise the plastidial members of the GGPPS family in tomato (Solanum lycopersicum) and their interaction with PSY isoforms.

The application of a biostimulant based on tannins affects root architecture and improves tolerance to salinity in tomato plants.

Roots have important roles for plants to withstand adverse environmental conditions, including salt stress. Biostimulant application was shown to enhance plant resilience towards abiotic stresses. Here, we studied the effect of a tannin-based biostimulant on tomato (Solanum lycopersicum L.

The santalene synthase from Cinnamomum camphora: Reconstruction of a sesquiterpene synthase from a monoterpene synthase.

Plant terpene synthases (TPSs) can mediate formation of a large variety of terpenes, and their diversification contributes to the specific chemical profiles of different plant species and chemotypes. Plant genomes often encode a number of related terpene synthases, which can produce very different terpenes. The relationship between TPS sequence and resulting terpene product is not completely understood.

The transition of Rhodobacter sphaeroides into a microbial cell factory.

Microbial cell factories are the workhorses of industrial biotechnology and improving their performances can significantly optimize industrial bioprocesses. Microbial strain engineering is often employed for increasing the competitiveness of bio-based product synthesis over more classical petroleum-based synthesis. Recently, efforts for strain optimization have been standardized within the iterative concept of "design-build-test-learn" (DBTL).

Analysis of wild tomato introgression lines elucidates the genetic basis of transcriptome and metabolome variation underlying fruit traits and pathogen response.

Wild tomato species represent a rich gene pool for numerous desirable traits lost during domestication. Here, we exploited an introgression population representing wild desert-adapted species and a domesticated cultivar to establish the genetic basis of gene expression and chemical variation accompanying the transfer of wild-species-associated fruit traits. Transcriptome and metabolome analysis of 580 lines coupled to pathogen sensitivity assays resulted in the identification of genomic loci associated with levels of hundreds of transcripts and metabolites.

MYB5-like and bHLH influence flavonoid composition in pomegranate.

The fruit of the pomegranate (Punica granatum L.) is an important nutraceutical food rich in polyphenolic compounds, including hydrolysable tannins, anthocyanins and flavonols. Their composition varies according to cultivar, tissue and fruit development stage and is probably regulated by a combination of MYB and bHLH type transcription factors (TFs).

Growth-uncoupled isoprenoid synthesis in .

Background: Microbial cell factories are usually engineered and employed for cultivations that combine product synthesis with growth. Such a strategy inevitably invests part of the substrate pool towards the generation of biomass and cellular maintenance. Hence, engineering strains for the formation of a specific product under non-growth conditions would allow to reach higher product yields.

A Biostimulant Seed Treatment Improved Heat Stress Tolerance During Cucumber Seed Germination by Acting on the Antioxidant System and Glyoxylate Cycle.

Seed enhancement technologies have the potential to improve germination and seedling growth under environmental stress. The effects of KIEM, an innovative biostimulant based on lignin derivatives and containing plant-derived amino acids and molybdenum, were investigated on cucumber ( L.) seed germination.

Plant Aromatic Prenyltransferases: Tools for Microbial Cell Factories.

In plants, prenylation of aromatic compounds, such as (iso)flavonoids and stilbenoids, by membrane-bound prenyltransferases (PTs), is an essential step in the biosynthesis of many bioactive compounds. Prenylated aromatic compounds have various health-beneficial properties that are interesting for industrial applications, but their exploitation is limited due to their low abundance in nature. Harnessing plant aromatic PTs for prenylation in microbial cell factories may be a sustainable and economically viable alternative.

Functional replacement of isoprenoid pathways in Rhodobacter sphaeroides.

Advances in synthetic biology and metabolic engineering have proven the potential of introducing metabolic by-passes within cell factories. These pathways can provide a more efficient alternative to endogenous counterparts due to their insensitivity to host's regulatory mechanisms. In this work, we replaced the endogenous essential 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for isoprenoid biosynthesis in the industrially relevant bacterium Rhodobacter sphaeroides by an orthogonal metabolic route.

Novel routes towards bioplastics from plants: elucidation of the methylperillate biosynthesis pathway from Salvia dorisiana trichomes.

Plants produce a large variety of highly functionalized terpenoids. Functional groups such as partially unsaturated rings and carboxyl groups provide handles to use these compounds as feedstock for biobased commodity chemicals. For instance, methylperillate, a monoterpenoid found in Salvia dorisiana, may be used for this purpose, as it carries both an unsaturated ring and a methylated carboxyl group.

Metabolic flux ratio analysis by parallel C labeling of isoprenoid biosynthesis in Rhodobacter sphaeroides.

Metabolic engineering for increased isoprenoid production often benefits from the simultaneous expression of the two naturally available isoprenoid metabolic routes, namely the 2-methyl-D-erythritol 4-phosphate (MEP) pathway and the mevalonate (MVA) pathway. Quantification of the contribution of these pathways to the overall isoprenoid production can help to obtain a better understanding of the metabolism within a microbial cell factory. Such type of investigation can benefit from C metabolic flux ratio studies.

Silencing of germacrene A synthase genes reduces guaianolide oxalate content in L.

Chicory ( L.) is a medicinal and industrial plant from the Asteraceae family that produces a variety of sesquiterpene lactones (STLs), most importantly bitter guaianolides: lactucin, lactucopicrin and 8-deoxylactucin as well as their modified forms such as oxalates. These compounds have medicinal properties; however, they also hamper the extraction of inulin - a very important food industry product from chicory roots.

Glucosinolate variability between turnip organs during development.

Turnip (Brassica rapa spp. rapa) is an important vegetable species, with a unique physiology. Several plant parts, including both the turnip tubers and leaves, are important for human consumption.

Toward Developing a Yeast Cell Factory for the Production of Prenylated Flavonoids.

Prenylated flavonoids possess a wide variety of biological activities, including estrogenic, antioxidant, antimicrobial, and anticancer activities. Hence, they have potential applications in food products, medicines, or supplements with health-promoting activities. However, the low abundance of prenylated flavonoids in nature is limiting their exploitation.

A MYB Triad Controls Primary and Phenylpropanoid Metabolites for Pollen Coat Patterning.

The pollen wall is a complex, durable structure essential for plant reproduction. A substantial portion of phenylpropanoids (e.g.

An analysis of characterized plant sesquiterpene synthases.

Plants exhibit a vast array of sesquiterpenes, C15 hydrocarbons which often function as herbivore-repellents or pollinator-attractants. These in turn are produced by a diverse range of sesquiterpene synthases. A comprehensive analysis of these enzymes in terms of product specificity has been hampered by the lack of a centralized resource of sufficient functionally annotated sequence data.