Synthetische Glykobiotechnologie

The field of synthetic glycobiotechnology encompasses the synthesis and modification of free carbohydrates and carbohydrates linked to biomolecules. Our group develops bio-catalytic processes for the synthesis of carbohydrate building blocks, so-called sugar nucleotides, and cell-free multi-enzyme cascades to tailor carbohydrates linked to proteins. The technology can eventually help to advance our understanding of the roles of specific carbohydrates in nutrition and medicine and contribute to human health and well-being.

Analysis of carbohydrates in Saponaria officinalis L. using GC/MS method

Saponaria officinalis L. (common soapwort), usually named fuller’s herb, is encountered in most of Europe, in Spain, France, Italy, for example, and also in Syria and North Africa. Saponaria officinalis L. is known in most of the world as an introduced species, often a weed, and sometimes as cultivated decorative plant. Saponaria officinalis contains a large amount of saponins, which foam during extraction with water. In addition to saponins, common soapwort also contains flavonoids, quillaic acid, fatty acids and different phenolic compounds. There is a lack of information about carbohydrates content of common soapwort. Thus the aim of this study was to determine the content of carbohydrates Saponaria officinalis L. herb and roots. The qualitative composition and quantitative content of carbohydrates in herb and roots of Saponaria officinalis L. were determined by using GC/MS method. The studies have shown that Saponaria officinalis L. herb is mainly composed of free carbohydrates such as D-glucose (3.65 mg/g), D-galactose (0.29 mg/g), D-fructose (0.20 mg/g) and D-saccharose (3.72 mg/g). In common soapwort herb, after acidic hydrolysis and derivatization with acetylated aldononitriles, D-arabinose, D-fucose, D-mannose, D-glucose, D-galactose, D-fructose and Myo-inositol were identified. Free carbohydrates in the roots of Saponaria officinalis L., including D-glucose, D-galactose and D-saccharose, were determined with GC/MS method too. D-saccharose was common among free carbohydrates of Saponaria officinalis L. in the largest amounts. Its content in herb and roots of the common soapwort was 3.72 mg/g and 25.39 mg/g respectively.

Determination of carbohydrates and fructans content in Cyperus esculentus L.

The tiger nut contains different active ingredients like oil, tannins, sterols, saponins, alkaloids, vitamins C and E, minerals, and resins. There is a lack of information about carbohydrates content of Cyperus esculentus L. Thus, the aim of this study was to determine the content of carbohydrates of tiger nut herb and tubers. The qualitative composition and quantitative content of carbohydrates in tubers and herb of tiger nut (Cyperus esculentus L.) were determined by using a GC/MS method. The results of analysis showed that tiger nut herb have free carbohydrates, namely D-saccharose, D-glucose, D-Mannitol, and D-fructose, while tubers have only disaccharide D-saccharose. Free D-saccharose presented in raw materials in the greatest amount, the content in tubers was 63.72 mg/g, in the herb – 9.79 mg/g, respectively. Monosaccharides and their derivatives after hydrolysis presented to D-glucose, D-xylose, D-galactose, D-arabinose in tubers, and D-xylose, D-glucose, D-arabinose, D-galactose, D-Dulcitol, D-Mannitol, D-mannose in the herb of tiger nut. D-glucose dominates in tubers and D-xylose in the herb, their content was 177.26 mg/g and 39.07 mg/g, respectively. The total content of fructans was determined by the spectrophotometric method. Its content was 13.49% in tubers and 8.78% in the herb of tiger nut.

DETERMINATION OF CARBOHYDRATES CONTENT IN GENTIANA CRUCIATA L. BY GC/MS METHOD

Objective: Thus, the aim of our research was to determine the qualitative composition and quantitative content of carbohydrates in the studied plant material with the prospect of its application as a medicinal plant raw material. Methods: The carbohydrates of the herb of Gentiana cruciata L. determined by GC/MS method. Identification of monosaccharides was based on comparing their retention times with retention times of standards of the mass spectral library NIST 02. Quantification was done by using sorbitol added to the sample. Results: The quantitative content of 4 free carbohydrates such as D-saccharose (38.39 mg/g), D-Pinitol (12.01 mg/g), D-glucose (10.05 mg/g) and D-fructose (1.69 mg/g) was established in the herb of Gentiana cruciata L. Also, this method established the qualitative composition and quantitative content of eight carbohydrates (monosaccharides and their derivatives after hydrolysis): D-glucose (29.66 mg/g), D-Pinitol (22.24 mg/g), L-arabinose (4.26 mg/g), D-galactose (3.55 mg/g), D-xylose (1.80 mg/g), L-rhamnose (1.49 mg/g), D-Dulcitol (0.76 mg/g) and D-mannose (0.44 mg/g). Conclusion: The results of the study showed that carbohydrates from the Gentiana cruciata L. can be used as important resources of new ingredients for the pharmaceutical industry.

Estimation of Biomass Enzymatic Hydrolysis State in Stirred Tank Reactor through Moving Horizon Algorithms with Fixed and Dynamic Fuzzy Weights

Second generation ethanol faces challenges before profitable implementation. Biomass hydrolysis is one of the bottlenecks, especially when this process occurs at high solids loading and with enzymatic catalysts. Under this setting, kinetic modeling and reaction monitoring are hindered due to the conditions of the medium, while increasing the mixing power. An algorithm that addresses these challenges might improve the reactor performance. In this work, a soft sensor that is based on agitation power measurements that uses an Artificial Neural Network (ANN) as an internal model is proposed in order to predict free carbohydrates concentrations. The developed soft sensor is used in a Moving Horizon Estimator (MHE) algorithm to improve the prediction of state variables during biomass hydrolysis. The algorithm is developed and used for batch and fed-batch hydrolysis experimental runs. An alteration of the classical MHE is proposed for improving prediction, using a novel fuzzy rule to alter the filter weights online. This alteration improved the prediction when compared to the original MHE in both training data sets (tracking error decreased 13%) and in test data sets, where the error reduction obtained is 44%.

Solving Nuisance Cyanobacteria Eutrophication Through Biotechnology

Management of nutrient inputs and usage of nuisance biomass as feedstock for bioenergy may be the solution of coastal lagoons eutrophication. We studied the species composition, photosynthetic pigments (Chl-a and Chl-c) and performance (OJIP-kinetics and JIP-test parameters), biochemistry (lipids and carbohydrates composition), and hydrogen production potential of Limnoraphis (Lyngbya) nuisance biomass collected from Lafri lagoon (1.24 km2) in Greece. The results showed that the removal of algal biomass from Lafri lagoon before its sedimentation, characterized by low Fν/Fm (0.42) and PItotal (2.67) values, and transfer of this in a simple, closed bioreactor, has the potential to produce hydrogen (H2), a renewable CO2-neutral energy that can directly be converted into electricity. The free carbohydrates of the lagoon water and that from the algal cells (42g glucose analogs per m3) could be also transferred to alcohols (biofuels), while the rest of the biomass could be used as organic fertilizer. The total lipid content (2.51%) of dry biomass composed primarily by palmitic acid was low. However, the presence of eicosapentaenoic (3.5%), and docosahexaenoic (1.7%), polyunsaturated fatty acids is worth mentioning. By harvesting and conversion of this coastal lagoon nuisance algal biomass to energy or other products, one could improve its water quality and, therefore, biodiversity and fish production; that is a sustainable solution of eutrophication necessary for the ongoing climatic change.

Photocatalyzed Transformation of Free Carbohydrates

In the growing context of sustainable chemistry, one of the challenges of organic chemists is to develop efficient and environmentally friendly methods for the synthesis of high-added-value products. Heterogeneous photocatalytic transformations have brought revolution in this regard, as they take advantage of an unlimited source of energy (solar light) or artificial UV light to onset organic chemical modifications. The abundance of free carbohydrates as chemical platform feedstock offers a great opportunity to obtain a variety of industrial interest compounds from biomass. Due to their chirality and polyfunctionality, the conversion of sugars generally requires multi-step protocols with protection/deprotection steps and hazardous chemical needs. In this context, several selective and eco-friendly methodologies are currently under development. This review presents a state of art of the recent accomplishments concerning the use of photocatalysts for the transformation and valorization of free carbohydrates. It discusses the approaches leading to the selective oxidation of free sugars, their degradation into organic chemicals, or their use for hydrogen production.

Greenland Ice Sheet exports labile organic carbon to the Arctic oceans

Runoff from small glacier systems contains dissolved organic carbon (DOC) rich in protein-like, low molecular weight (LMW) compounds, designating glaciers as an important source of bioavailable carbon for downstream heterotrophic activity. Fluxes of DOC and particulate organic carbon (POC) exported from large Greenland catchments, however, remain unquantified, despite the Greenland Ice Sheet (GrIS) being the largest source of global glacial runoff (ca. 400 km3 yr−1). We report high and episodic fluxes of POC and DOC from a large (>600 km2) GrIS catchment during contrasting melt seasons. POC dominates organic carbon (OC) export (70–89% on average), is sourced from the ice sheet bed, and contains a significant bioreactive component (9% carbohydrates). A major source of the "bioavailable" (free carbohydrate) LMW–DOC fraction is microbial activity on the ice sheet surface, with some further addition of LMW–DOC to meltwaters by biogeochemical processes at the ice sheet bed. The bioavailability of the exported DOC (26–53%) to downstream marine microorganisms is similar to that reported from other glacial watersheds. Annual fluxes of DOC and free carbohydrates during two melt seasons were similar, despite the approximately two-fold difference in runoff fluxes, suggesting production-limited DOC sources. POC fluxes were also insensitive to an increase in seasonal runoff volumes, indicating a supply limitation in suspended sediment in runoff. Scaled to the GrIS, the combined DOC (0.13–0.17 Tg C yr−1 (±13%)) and POC fluxes (mean = 0.36–1.52 Tg C yr−1 (±14%)) are of a similar order of magnitude to a large Arctic river system, and hence may represent an important OC source to the near-coastal North Atlantic, Greenland and Labrador seas.