Disaccharides Sucrose Research Articles

Biosynthesis of nonnutritive monosaccharide d-allulose by metabolically engineered Escherichia coli from nutritive disaccharide sucrose.

Sucrose is a commonly utilized nutritive sweetener in food and beverages due to its abundance in nature and low production costs. However, excessive intake of sucrose increases the risk of metabolic disorders, including diabetes and obesity. Therefore, there is a growing demand for the development of nonnutritive sweeteners with almost no calories. d-Allulose is an ultra-low-calorie, rare six-carbon monosaccharide with high sweetness, making it an ideal alternative to sucrose. In this study, we developed a cell factory for d-allulose production from sucrose using Escherichia coli JM109 (DE3) as a chassis host. The genes cscA, cscB, cscK, alsE, and a6PP were co-expressed for the construction of the synthesis pathway. Then, the introduction of ptsG-F and knockout of ptsG, fruA, ptsI, and ptsH to reprogram sugar transport pathways resulted in an improvement in substrate utilization. Next, the carbon fluxes of the Embden-Meyerhof-Parnas and the pentose phosphate pathways were regulated by the inactivation of pfkA and zwf, achieving an increase in d-allulose titer and yield of 154.2% and 161.1%, respectively. Finally, scaled-up fermentation was performed in a 5 L fermenter. The titer of d-allulose reached 11.15 g/L, with a yield of 0.208 g/g on sucrose.

Comparative metabolome variation in Brassica juncea different organs from two varieties as analyzed using SPME and GCMS techniques coupled to chemometrics

Indian mustard (Brassica juncea; Brassicaceae) is an edible, oilseeds-yielding crop widely consumed as a food spice owing to its richness in nutrients with several health benefits. The current study aims to dissect the B. juncea metabolome heterogeneity among its different organs including leaf, stem, flower, and seed. Moreover, assessing the metabolome differences between two different varieties RH-725 and RH-761 grown at the same conditions. Gas chromatography-mass spectrometry (GC–MS) post-silylation was used to dissect the composition of nutrient metabolites coupled to multivariate data analysis. Variation in sulphur aglycones was measured using headspace-solid phase-microextraction HS-SPME coupled to GC–MS. A total of 101 nutrient metabolites were identified with the abundance of sugars represented by monosaccharides in all organs, except for seeds which were enriched in disaccharides (sucrose). α-Linolenic acid was detected as a marker fatty acid in leaf from RH-725 at 12.5 µg/mg. Malic acid was detected as a significant variant metabolite between the two varieties as detected in the leaf from the RH-725 variety at ca. 128.2 µg/mg compared to traces in RH-761. 7 Volatile sulphur compounds were detected at comparable levels in RH-725 and RH-761, with 3-butenyl isothiocyanate was the most abundant at 0.8–2 ng/mg.

Predicting the Stability of Formulations Containing Lyophilized Human Serum Albumin and Sucrose/Trehalose Using Solid-State NMR Spectroscopy.

Stabilization of proteins by disaccharides in lyophilized formulations depends on the interactions between the protein and the disaccharide (system homogeneity) and the sufficiently low mobility of the system. Human serum albumin (HSA) was lyophilized with disaccharides (sucrose and/or trehalose) in different relative concentrations. Solid-state nuclear magnetic resonance (ssNMR) spectroscopy 1H T1 and 1H T1ρ relaxation times were measured to determine the homogeneity of the lyophilized systems on 20-50 and 1-3 nm domains, respectively, with 1H T1 relaxation times also being used to determine the β-relaxation rate. HSA/sucrose systems had longer 1H T1 relaxation times and were slightly more stable than HSA/trehalose systems in almost all cases shown. HSA/sucrose/trehalose systems have 1H T1 relaxation times between the HSA/sucrose and HSA/trehalose systems and did not result in a more stable system compared with binary systems. Inhomogeneity was evident in a sample containing relative concentrations of 10% HSA and 90% trehalose, suggesting trehalose crystallization during lyophilization. Under these stability conditions and with these ssNMR acquisition parameters, a 1H T1 relaxation time below 1.5 s correlated with an unstable sample, regardless of the disaccharide(s) used.

Comparison of Sucrose and Trehalose for Protein Stabilization Using Differential Scanning Calorimetry.

The disaccharide trehalose is generally acknowledged as a superior stabilizer of proteins and other biomolecules in aqueous environments. Despite many theories aiming to explain this, the stabilization mechanism is still far from being fully understood. This study compares the stabilizing properties of trehalose with those of the structurally similar disaccharide sucrose. The stability has been evaluated for the two proteins, lysozyme and myoglobin, at both low and high temperatures by determining the glass transition temperature, Tg, and the denaturation temperature, Tden. The results show that the sucrose-containing samples exhibit higher Tden than the corresponding trehalose-containing samples, particularly at low water contents. The better stabilizing effect of sucrose at high temperatures may be explained by the fact that sucrose, to a greater extent, binds directly to the protein surface compared to trehalose. Both sugars show Tden elevation with an increasing sugar-to-protein ratio, which allows for a more complete sugar shell around the protein molecules. Finally, no synergistic effects were found by combining trehalose and sucrose. Conclusively, the exact mechanism of protein stabilization may vary with the temperature, as influenced by temperature-dependent interactions between the protein, sugar, and water. This variability can make trehalose to a superior stabilizer under some conditions and sucrose under others.

Structural basis for sugar perception by Drosophila gustatory receptors.

Insects rely on a family of seven transmembrane proteins called gustatory receptors (GRs) to encode different taste modalities, such as sweet and bitter. We report structures of Drosophila sweet taste receptors GR43a and GR64a in the apo and sugar-bound states. Both GRs form tetrameric sugar-gated cation channels composed of one central pore domain (PD) and four peripheral ligand-binding domains (LBDs). Whereas GR43a is specifically activated by the monosaccharide fructose that binds to a narrow pocket in LBDs, disaccharides sucrose and maltose selectively activate GR64a by binding to a larger and flatter pocket in LBDs. Sugar binding to LBDs induces local conformational changes, which are subsequently transferred to the PD to cause channel opening. Our studies reveal a structural basis for sugar recognition and activation of GRs.

Formulation factors affecting foam properties during vacuum foam-drying

This paper explores how vacuum foam-drying of a protein is influenced by formulation parameters by investigating the foam structure, physical properties of the foam, and the stability of the protein. Recombinant human bile salt-stimulated lipase was used as a model of a protein drug. The stability of the lipase was evaluated through activity measurements. Two disaccharides (sucrose and trehalose), strongly tending to an amorphous form, were used as matrix formers, and the physical properties were assessed through residual water content, glass transition temperature, and crystalline state. Moreover, some formulations included surfactants with different sizes and structures of the head group. The alkyl chain length was kept constant to only investigate the impact of the surfactant head group, in the presence of the lipase, on the foamability and surface coverage of the lipase. The study demonstrated that the lipase allowed for a dry, solid foam with a foam overrun of up to 2600 %. The wall thickness of the dry, solid foam was estimated to be 20–50 µm. Clear differences between sucrose and trehalose as matrix former were identified. The lipase showed no tendency to lose activity because of the drying and rehydration, despite a proportion of the lipase covering the surfaces of the dry material.

Water content, transition temperature and fragility influence protection and anhydrobiotic capacity

Water is essential for metabolism and all life processes. Despite this, many organisms distributed across the kingdoms of life survive near-complete desiccation or anhydrobiosis. Increased intracellular viscosity, leading to the formation of a vitrified state is necessary, but not sufficient, for survival while dry. What properties of a vitrified system make it desiccation-tolerant or -sensitive are unknown. We have analyzed 18 different in vitro vitrified systems, composed of one of three protective disaccharides (trehalose, sucrose, or maltose) and glycerol, quantifying their enzyme-protective capacity and their material properties in a dry state. Protection conferred by mixtures containing maltose correlates strongly with increased water content, increased glass-transition temperature, and reduced glass former fragility, while the protection of glasses formed with sucrose correlates with increased glass transition temperature and the protection conferred by trehalose glasses correlates with reduced glass former fragility. Thus, in vitro different vitrified sugars confer protection through distinct material properties. Next, we examined the material properties of a dry desiccation tolerant and intolerant life stage from three different organisms. The dried desiccation tolerant life stage of all organisms had an increased glass transition temperature and reduced glass former fragility relative to its dried desiccation intolerant life stage. These results suggest in nature organismal desiccation tolerance relies on a combination of various material properties. This study advances our understanding of how protective and non-protective glasses differ in terms of material properties that promote anhydrobiosis. This knowledge presents avenues to develop novel stabilization technologies for pharmaceuticals that currently rely on the cold-chain. Statement of significanceFor the past three decades the anhydrobiosis field has lived with a paradox, while vitrification is necessary for survival in the dry state, it is not sufficient. Understanding what property(s) distinguishes a desiccation tolerant from an intolerant vitrified system and how anhydrobiotic organisms survive drying is one of the enduring mysteries of organismal physiology. Here we show in vitro the enzyme-protective capacity of different vitrifying sugars can be correlated with distinct material properties. However, in vivo, diverse desiccation tolerant organisms appear to combine these material properties to promote their survival in a dry state.

Races and Biovar Characterization of Ralstonia solanacearum Causing Bacterial Wilt Disease of Potato

Ralstonia solanacearum, the causative agent of brown rot/bacterial wilt, is a major cause of severe potato illnesses in many impoverished nations located in tropical and subtropical regions of the world. When it occurs, the disease is to blame for significant losses to the potato industry. The illness has the potential to completely destroy a crop and stop using a piece of land for potato cultivation for a number of years. A survey was carried out to investigate the extent of Ralstonia solanacearum-caused bacterial wilt of potato crops in important potato-growing talukas in the Banaskantha district of Gujarat, India, including Deesa, Dantiwada, Palanpur, and Amirgadh. The frequency of bacterial wilt disease in potatoes is rather low in this region. Four talukas were utilised to identify ten isolates (RsSt1 to RsSt10) of R. solanacearum, which were then used to determine the biovar and race. Gram-negative rod-shaped cells were present in the isolates of R. solanacearum. On TZC agar medium, these isolates developed colonies that were creamy or dull white in colour with a hint of pink or red in the centre. The oxidation of disaccharides (sucrose, lactose, maltose) and sugar alcohols (manitol, sorbitol, and dulcitol) by R. solanacearum isolates was used to determine the biovar characteristics. This revealed that, of the ten isolates, eight were classified as bv2, and the two remaining isolates (RsSt5 and RsSt7) belonged to bv2T. The pathogenicity test conducted on tobacco, tomato, and brinjal allowed for the race identification of R. solanacearum isolates, which were classified as race 3 due to their limited host range and ability to exclusively elicit wilt symptoms in potatoes and tomatoes. As a result, Races 3 and bv2 and bv2T were represented among the R. solanacearum isolates that caused bacterial wilt of potatoes in the Banaskantha district.

Effect of blister blight disease caused by Exobasidium on tea quality

Blister blight, as one of the most threatening and damaging disease worldwide, mainly infects young organs and tissues seriously affecting tea growth and quality. In this study, the spread of pathogen on tea leaves were examined by toluidine blue staining, scanning electron microscope and transmission electron microscope analysis. The composition and abundance of fungal community on leaf tissues were firstly analyzed. Sensory evaluation and metabolites analysis indicated that diseased tea leaves had strong sweet taste and soluble sugars contributed significantly to the taste, while metabolites showing bitter and astringent taste (caffeine, catechins) were significantly decreased. According to the biological functions of differential metabolites, sugars including 7 monosaccharides (d-xylose, d-arabinose, d-mannose, d-glucuronic acid, glucose, d-galactose and d-fructose), 2 disaccharide (sucrose and maltose) and 1 trisaccharide (raffinose) were the main differential sugars increased in content (>2 fold change), which was of great significance to sweet taste of diseased tea.

Effect of Osmolytes on Photoassembly of Functionally Active Mn4CaO5 Cluster in Mn-Depleted Photosystem II Preparations Isolated from Spinach Leaves

The effect of osmolytes (trehalose, sucrose, betaine, D-glucose and hydroxyectoine) on the photoassembly of the functionally active inorganic core of the water-oxidizing complex (Mn4CaO5 cluster) in Mn-depleted PSII preparations (apo-WOC-PSII) was investigated. It was revealed that the efficiency of the photoassembly of the Mn4CaO5 cluster was considerably (three times) increased in the presence of 1 M disaccharides (trehalose or sucrose) in contrast to other osmolytes. It was found that the osmolytes (especially trehalose or sucrose) improved the redox interaction of exogenous Mn2+ with apo-WOC-PSII, enhanced the protective effect of Mn2+ against the photoinhibition of apo-WOC-PSII, protected CaCl2-treated PSII preparations against thermoinactivation, and stabilized the water-oxidizing complex and electron transport from QA to QB in native PSII preparations during heat treatment. It is suggested that the ability of osmolytes to enhance the efficiency of the photoassembly of a Mn4CaO5 cluster depends on their effect on the following key processes: the redox interaction of Mn2+ with apo-WOC-PSII; the stability of apo-WOC-PSII to photoinhibition during the photoactivation procedure; and the stabilization of both the newly assembled functionally active Mn4CaO5 cluster and the electron transfer from QA to QB.

Online Coupling of Size Exclusion Chromatography to Capillary Enhanced Raman Spectroscopy for the Analysis of Proteins and Biopharmaceutical Drug Products.

The online coupling of size exclusion chromatography (SEC) to capillary enhanced Raman spectroscopy (CERS) based on a liquid core waveguide (LCW) flow cell was applied for the first time to assess the higher-order structure of different proteins. This setup allows recording of Raman spectra of the monomeric protein within complex mixtures, since SEC enables the separation of the monomeric protein from matrix components such as excipients of a biopharmaceutical product and higher molecular weight species (e.g., aggregates). The acquired Raman spectra were used for structural elucidation of well characterized proteins such as bovine serum albumin, hen egg white lysozyme, and β-lactoglobulin and of the monoclonal antibody rituximab in a medicinal product. Additionally, the CERS detection of the disaccharide sucrose, which is used as a stabilizing excipient, was quantified to achieve a limit of detection (LOD) of 120 μg and a limit of quantification (LOQ) of 363 μg injected on the column.

Role of sugars in the inactivation of horseradish peroxidase induced by cold atmospheric plasma

This study investigated the effect of different CAP exposures on the activity of horseradish peroxidase (HRP) in phosphate buffer and in model systems with different concentrations of monosaccharides (glucose, fructose) and disaccharides (sucrose, trehalose) to evaluate the potential role of sugars in enzyme inactivation. Spectroscopic analyses (fluorescence, circular dichroism, UV–Vis absorption) were conducted to highlight structural modifications possibly responsible for HRP inactivation. In phosphate buffer, the inactivation of HRP by CAP resulted dependent on both the treatment time (up to 70% after 30 min) and ozone concentration in the chamber. HRP residual activity was fitted with a very good approximation by the Weibull model. Sugars reduced the CAP efficacy, and this effect was concentration-dependent and much higher for disaccharides than monosaccharides. UV and fluorescence spectra showed that sugars differently preserved HRP tertiary structure, hindering heme degradation and quenching of aromatic amino acids. Likewise, sugars differently affected the loss of secondary structures. These findings only partially explained the diverse protective effects of sugars on HRP. Other factors, such as the different sugars’ abilities to quench plasma reactive species, reduce the system mobility, and stabilize proteins by preserving their hydration shell, were retained to play a role in the reduction of HRP inactivation. This study deepened the knowledge of the effect of CAP on peroxidase activity and demonstrated that the presence of mono and disaccharides, naturally found in fruits and vegetables and widely employed in food and beverage industries, can mitigate the inactivation and structural alterations induced by CAP on peroxidase enzymes.

Phase behaviour and structural properties of SOPC model lipid system in a sucrose solution

Lipid membranes are an important component of the biological cell. The profound understanding of their structure and functionality, as well as, the influence of various biologically relevant admixtures on their main characteristics is of great importance for research and development in medicine and pharmacology. The effect of sugars on the behaviour of the membrane cell enjoys an ever-increasing interest as they are biologically significant substances. We have studied the influence of the disaccharide sucrose on the physicochemical properties of SOPC (1-stearoyl-2-oleoyl-sn- glycero-3-phosphocholine) lipid system aiming to gain better understanding of the mechanisms of the interaction between both substances. For that purpose, we have used differential scanning calorimetry and Fourier-transform infrared spectroscopy. Our results show that adding sugar up to 300 mM concentration substantially alters the thermodynamic and structural properties of SOPC. The DSC thermograms at heating reveal a general lowering of the SOPC transition temperature Tm from gel to liquid crystalline phase (main phase transition, ordered-disordered phase transition) in the presence of sugar. The corresponding peaks are smeared and harder to trace. In agreement with this, a gradual decrease of the enthalpy values up to 300 mM was measured. The IR spectroscopy study provided spectral evidence for two states of hydration of the phosphate groups in the sugar-SOPC model systems suggesting a mechanism of interaction where only part of the phospholipid headgroups are hydrogen bonded to the sugar molecules. The obtained results are in good agreement with various earlier data including results about the bending elasticity moduli, as well as, some theoretical simulations on the sugar-lipid interactions. The current results also reinforce the potential of sucrose to be used as a cell protector against drought at, both, high and low temperatures.

Automatization of metabolite extraction for high-throughput metabolomics: case study on transgenic isoprene-emitting birch.

Metabolomics studies are becoming increasingly common for understanding how plant metabolism responds to changes in environmental conditions, genetic manipulations and treatments. Despite the recent advances in metabolomics workflow, the sample preparation process still limits the high-throughput analysis in large-scale studies. Here, we present a highly flexible robotic system that integrates liquid handling, sonication, centrifugation, solvent evaporation and sample transfer processed in 96-well plates to automatize the metabolite extraction from leaf samples. We transferred an established manual extraction protocol performed to a robotic system, and with this, we show the optimization steps required to improve reproducibility and obtain comparable results in terms of extraction efficiency and accuracy. We then tested the robotic system to analyze the metabolomes of wild-type and four transgenic silver birch (Betula pendula Roth) lines under unstressed conditions. Birch trees were engineered to overexpress the poplar (Populus × canescens) isoprene synthase and to emit various amounts of isoprene. By fitting the different isoprene emission capacities of the transgenic trees with their leaf metabolomes, we observed an isoprene-dependent upregulation of some flavonoids and other secondary metabolites as well as carbohydrates, amino acid and lipid metabolites. By contrast, the disaccharide sucrose was found to be strongly negatively correlated to isoprene emission. The presented study illustrates the power of integrating robotics to increase the sample throughput, reduce human errors and labor time, and to ensure a fully controlled, monitored and standardized sample preparation procedure. Due to its modular and flexible structure, the robotic system can be easily adapted to other extraction protocols for the analysis of various tissues or plant species to achieve high-throughput metabolomics in plant research.

Stem Carbohydrate Richness in Two Cycad Species

The pachycaulous stem of cycad plants enables the storage of abundant nonstructural carbohydrates. Cycas revoluta Thunb. and Zamia furfuracea L.f. stems were analyzed for starch and 15 sugars to determine carbohydrate richness. All 15 sugars were detected in both species. The tetrasaccharide stachyose and the disaccharide sucrose comprised most of the sugar content. Total sugar content of these cycad stems was 330 to 360 mg·g−1 and was similar to starch content. The stems of these two species were composed of 64% to 79% nonstructural carbohydrates. The cycad stem is ideally designed to store and mobilize nonstructural carbohydrates to support sink activity when needed, and stachyose may play a prominent functional role.

Investigation of Arginine deiminase activity in B. cereus and R. eutropha under minimal conditions

Prokaryotes form an important part of our lives. These microorganisms, which we can not see with the naked eye, are used in medicine, biotechnology, microbiology and many other fields. They can produce many anti-cancer enzymes (Arginine deiminase, Asparaginase, Methionine gamma lyase etc.). In this study, an important bacterial anti-tumor enzyme of Bacillus cereus and R. eutropha in the presence of different minimal sources (Dextrose, Fructose, Glucose, Xylose, Maltose, Nutrient Broth Ramnose, Ribose, Sucrose) under static and shaking (150 rpm) conditions. Arginine deiminase activity was searched. In accordance with conclisions of our study, these microorganisms showed the highest ADI activity in the disaccharide medium, maltose and sucrose, and in the aldose group, in the ribose medium. It has been shown that this enzyme, which is used in cancer treatment, can be produced more cheaply and easily in minimal environments.

Evaluation of source material for sweet maize by the main breeding characteristics

Topicality. The sweet maize grain differs from other maize subspecies in its high sugar content: the grain accumulates 2 times more mono- and disaccharides, 20 times more dextrins, and almost 2 times less starch, with a crude protein content of 10.4–14.9 %. The main direction of sweet maize breeding is to develop the high-yielding interline hybrids that are suitable for mechanized harvesting of cobs, and resistant to main diseases and pests, as well as characterized by high technological grain qualities. To effectively solve these challenges, it is necessary to know the morphological and biological characteristics and properly select the source material (self-pollinated lines). Purpose. To study of morphological and biological characteristics of sweet maize lines. Materials and methods. Visual phenological observations; laboratory-field method was used to determine morpho-biological characteristics of plants; measuring and weighing method – to determine yield and metric characteristics of plants; mathematical and statistical method - to determinate validity of results, variability of traits, correlational dependence of traits; analysis of variance; comprehensive assessment of morpho-biological and economically valuable characteristics of inbred lines. Results. According to analysis of sugar composition, the studied samples revealed a high content of monosaccharides (glucose, fructose, etc.) in the lines HOL-1 1411111, HOL-1 1411211, DKS346 114, DINAR346 141, HOL-19 and disaccharides (sucrose, lactose, maltose) in HOL-1 1411211, SVAN1212 123, HOL-19. These indicators are important in the deep processing of sweet maize for the food industry an individual product and as one of the components in the culinary products. These mono- and disaccharides are used to produce sweets, sweet or alcoholic drinks and sauces. The following DINAR346 141, HOL-1 1411511 lines had a low level of sucrose content: 3.7 and 4.6 %, respectively. Conclusions. According to the results of research on the breeding material of sweet maize, it was identified the self-pollinated families with high taste qualities (7 points), such as HOL-1 1411111, HOL-1 1411211, DKS346 114, HOL-4 1411141 and HOL-19, which will be involved to develop competitive high-yielding hybrids with a high sugar content in grain, increased taste and technological qualities in the sweet maize breeding programs in the future. Key words: sweet corn, line, sugar content, seed productivity, grain taste

Quantification methods for carbohydrate compounds in biologicals: a review

Carbohydrate compounds are widely used as fillers and stabilisers in biological products. When present, these compounds guarantee that the active pharmaceutical ingredient will remain stable during production, transportation, and storage. At the same time, pharmacopoeias standardise the excipient content and require that excipients should be quantified for assessing the quality of biological products.The aim of the study was to identify promising methods for the development of quantification procedures for carbohydrate compounds in biological products.The authors analysed regulatory documents for biological products approved in the Russian Federation. The most widely used excipients, both individually and in combinations, are polyols (sorbitol and mannitol), monosaccarides (glucose), and disaccharides (trehalose, sucrose, lactose, and maltose). Using literature data, the authors reviewed the methods used for quantifying polyols, monosaccharides, and disaccharides to assess the quality of biological products. Quantitative determination of carbohydrate stabilisers employs titrimetric, spectrophotometric, enzymatic, and chromatographic methods. This review presents an analysis of the advantages and disadvantages of these methods. It highlights the advantages of ionic HPLC with amperometric detection and hydrophilic HPLC with refractometric and evaporative light scattering detection, which are sufficiently selective and can identify substances without prior derivatisation. In conclusion, ionic and hydrophilic HPLC methods are a promising base for the development of quantification procedures for carbohydrate stabilisers.

Screening of Strains of the Medicinal Mushroom Fomitopsis officinalis (vill.) Bondartsev & Singer Promising for Biotechnological Use

Background. Macromycete cultivation methods development will contribute to the production of biotechnological products based on fungus. Determination of the main factors affecting medicinal macromycetes’ life processes allows to control biosynthetic activity of a fungal organism and obtain biotechnological products based on it. Objective. Screening of Fomitopsis officinalis strains promising for biotechnological use, and determining of physico-chemical factors that affect the cultures life processes. Methods. The objects of the study were three pure cultures of F. officinalis (IBK-2497, IBK-2498, IBK-5004). The influence of the acidity of the environment on the growth of mycelium, the needs of the cultures in the sources of carbon and nitrogen nutrition were determined. The following carbon sources were used: monosaccharides (glucose, xylose), disaccharides (sucrose, lactose) and trisaccharides (raffinose), polysaccharides (starch); nitrogen sources: KNO3, (NH4)2HPO4, asparagine, peptone. Dynamics of the culture growth were determined under the conditions of deep cultivation, on a liquid nutrient medium of glucose-peptone-yeast extract (GPA), g/l: glucose – 30.0; peptone – 3.5; yeast extract – 2.0; KH2PO4 – 1.0; K2HPO4 – 1.0; MgSO4×7H2O – 0.25. Results. The pH range between 5.5 and 6.0 was the most favorable for active growth of all studied strains of F. officinalis. The best carbon sources for growth were glucose and starch; peptone and asparagine were the best source of nitrogen. Nutrient media with xylose, lactose and nitrate nitrogen were least suitable for growth. Analysis of the strains growth dynamics on the GPA medium showed that the largest mass of mycelium (up to 11.54 ± 0.2 g/l) was produced by culture F. officinalis IBK-5004 on the 10-th day of cultivation. Cultures F. officinalis IBK-2497, IBK-2498 grew slower, and the mycelial mass was 10.33 ± 0.2 and 9.68 ± 0.3 g/l on the 14-th day of cultivation. Conclusions. Based on the obtained data, the F. officinalis IBK-5004 strain was selected. It can be considered a promising mycelial mass producer based on the set of characteristics.

Polarimetric and fluorescence spectroscopic based classification of mono and disaccharide solutions

In this article, we demonstrate the potential application of polarimetry and fluorescence spectroscopy for classifying mono and disaccharides (sugar) both qualitatively and quantitatively. A phase lock-in rotating analyzer (PLRA) polarimeter has been designed and developed for real time quantification of sugar concentration in a solution. Polarization rotation in the form of phase shift in sinusoidal photovoltages of reference and sample beams occurred when incident on the two spatially distinct photodetectors. Monosaccharide (fructose and glucose) and disaccharide (sucrose) have been quantitatively determined with sensitivities of 122.06 deg ml g−1, 272.84 deg ml g−1 and 163.41 deg ml g−1 respectively. Calibration equations have been obtained from the respective fitting functions to estimate the concentration of each individual dissolved in deionized (DI) water. In comparison to the predicted results, the absolute average errors of 1.47 %, 1.63 % and 1.71 % are calculated for the readings of sucrose, glucose and fructose, respectively. Furthermore, the performance of the PLRA polarimeter has been compared with fluorescence emission results acquired from the same set of samples. The Limit of detections (LODs) attained from both experimental setups are comparable for mono and disaccharides. A linear detection response is observed by both polarimeter and fluorescence spectrometer in a wide range 0–0.28 g/ml of sugar. These results depict that PLRA polarimeter is novel, remote, precise and cost-effective for quantitative determination of optically active ingredient in the host solution.