Impact Of Glycerol Research Articles

Development of highly reusable, mechanically stable corn starch-based aerogel using glycerol for potential application in the storage of fresh spinach leaves

Impact of glycerol on the physico-functional, morphological, mechanical, and rehydration properties of corn starch-based aerogel has been investigated. The aerogel was prepared from hydrogel (sol-gel method) using solvent exchange and supercritical CO2 drying. Glycerol-infused aerogel had a more connected, denser structure (0.38–0.45 g/cm3), enhanced hygroscopic behavior, and was reusable up to eight times in terms of its capacity to absorb water after being drawn from the soaked sample. However, the inclusion of glycerol reduced the aerogel's porosity (75.89–69.91 %) and water absorption rate (WAR; 118.53–84.64 %) but enhanced its percentage shrinkage (75.03–77.99 %) and compressive strength (26.01–295.06 N). The most effective models for describing the rehydration behavior of aerogel were determined to be the Page, Weibull, and Modified Peleg models. Glycerol addition improved the internal strength of the aerogel so could be recycled without significant change in the physical characteristics of the aerogel. By effectively eliminating the condensed moisture that was developed inside the packing owing to the transpiration of fresh spinach leaves, the aerogel extended the storage life of the leaves by up to eight days. The glycerol-based aerogel has the potential to be employed as a carrier matrix for various chemicals and a moisture scavenger.

The Impact of Glycerol on an Affibody Conformation and Its Correlation to Chemical Degradation.

The addition of glycerol to protein solutions is often used to hinder the aggregation and denaturation of proteins. However, it is not a generalised practice against chemical degradation reactions. The chemical degradation of proteins, such as deamidation and isomerisation, is an important deteriorative mechanism that leads to a loss of functionality of pharmaceutical proteins. Here, the influence of glycerol on the chemical degradation of a protein and its correlation to glycerol-induced conformational changes is presented. The time-dependent chemical degradation of a pharmaceutical protein, GA-Z, in the absence and presence of glycerol was investigated in a stability study. The effect of glycerol on protein conformation and oligomerisation was characterised using asymmetric field-flow fractionation and small-angle neutron scattering in a wide glycerol concentration range of 0–90% v/v. The results from the stability study were connected to the observed glycerol-induced conformational changes in the protein. A correlation between protein conformation and the protective effect of glycerol against the degradation reactions deamidation, isomerisation, and hydrolysis was found. The study reveals that glycerol induces conformational changes of the protein, which favour a more compact and chemically stable state. It is also shown that the conformation can be changed by other system properties, e.g., protein concentration, leading to increased chemical stability.

Biomass-glycerol briquettes are not necessarily mechanically stable and energetically effective

The re-use of glycerol from biodiesel industry as an alternative lubricant for making high-performance briquettes is usual. However, the technical performance of this agro-industrial residue is not consistent. This study outlines, accordingly, the real risk of introducing glycerol into the co-briquetting of highly caloric by-products of energy-crops. The production of hybrid briquettes consisted of pressing mixtures of residues of sugarcane and sorghum with the liquid additive at 10, 20, and 30 wt.% in bench-scale hydraulic piston presser machine. Irrespective of the blend, briquettes containing the supplement at the highest level as part of their composition ended up being much more hygroscopic (20.10%) and less energetic (3.15 GJ m−3). The explanation for the negative impact of glycerol on the thermomechanical behavior of briquettes would be overconcentration of additive capable of effectively defying compacting biomass. The degree of compaction during co-briquetting has likely gone down quickly with a maximizing level of glycerol. As long as the additive is not able to lubricate the feedstock suitably, improbability of biomass particles to successfully bond together to form themselves into mechanically stable and energetically effective briquettes is large. Besides lower density (273.80 kg m−3) and higher relaxation (22.75%), briquettes with glycerol at 30 wt.% generally were aesthetically unpleasing. Practically, these products resisted no longer to handling, transportation, and storage. They lost their shape easily during emptying and shifting them, thus, releasing larger quantities of biomass to the environment. Preliminary evidence of high-viscosity glycerol capable of limiting safe and effective production of high-performance briquettes for heating and power exists.

Urine metabolome alterations in malnutrition and the impact of glycerol or rumen-protected choline chloride supplementation in advanced pregnant ewes

The objective of this study was to explore the metabolic profiles of pregnancy malnutrition induced by feed restriction (FR) and the counteracting effects of glycerol and rumen-protected choline chloride supplementation. Two feeding trials were conducted. In the first experiment, twenty pregnant Hu sheep carrying multiple fetuses with a gestation period of 108 d were randomly divided into two groups. The ewes in the control (CON) group were offered 100 % of their nutritional requirements as recommended by the National Research Council (NRC), while the FR group was offered 30 % of feed intake of CON for 15 d. In the second experiment, eighteen pregnant Hu sheep were offered a feed intake comprising 30 % of the NRC-recommended nutritional requirements twice daily. The sheep were randomly divided into three groups: the FR group in the second experiment (FR2), with no supplementation, the glycerol (GLY) group, which received 40 ml of glycerol per d, and the rumen-protected choline chloride (RPC) group, which received 10 g of rumen-protected choline chloride per d for 9 d. In the first experiment, the urine metabolome of sixteen ewes showed significant difference between the CON group and FR group. Compared with the CON group, FR decreased the level of d-glucose, lactic acid, levoglucosan, α-ketoglutarate, phosphohydroxypyruvic acid, glucose 6-phosphate and the methyl donors, while increasing the level of pyruvate, fumaric acid and carnitines in urine. Both the GLY and RPC treatments counteracted some of these changes and modulated the urine metabolome in advanced pregnant ewes suffering from malnutrition.

Ovotransferrin nanofibril formation in the presence of glycerol or sorbitol

Impact of glycerol and sorbitol on assembly of iron-bound ovotransferrin (OVT) into nanofibrils was investigated. Thioflavin T fluorescence result indicated that the presence of glycerol or sorbitol could reduce the rate of OVT fibrillation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis demonstrated that 60% sorbitol could retard hydrolysis of OVT completely for a period of time during thermal treatment, and decoupling hydrolysis from fibril self-assembly helped to identify the building blocks of OVT nanofibrils. OVT nanofibrils were composed of both intact OVT monomers and OVT-derived peptides. Influence of glycerol and sorbitol on morphology of OVT nanofibrils was studied using atomic force microscopy. The presence of glycerol or sorbitol shortened OVT nanofibrils, and the presence of 60% glycerol or sorbitol could increase thickness of OVT nanofibrils. Hopefully, this work may provide new insight about building blocks of protein nanofibrils and impact of polyols on protein fibrillation.

Impact of Glycerol as Carbon Source onto Specific Sugar and Inducer Uptake Rates and Inclusion Body Productivity in E. coli BL21(DE3).

The Gram-negative bacterium E. coli is the host of choice for a multitude of used recombinant proteins. Generally, cultivation is easy, media are cheap, and a high product titer can be obtained. However, harsh induction procedures using isopropyl β-d-1 thiogalactopyranoside as inducer are often referred to cause stress reactions, leading to a phenomenon known as “metabolic” or “product burden”. These high expressions of recombinant proteins mainly result in decreased growth rates and cell lysis at elevated induction times. Therefore, approaches tend to use “soft” or “tunable” induction with lactose and reduce the stress level of the production host. The usage of glucose as energy source in combination with lactose as induction reagent causes catabolite repression effects on lactose uptake kinetics and as a consequence reduced product titer. Glycerol—as an alternative carbon source—is already known to have positive impact on product formation when coupled with glucose and lactose in auto-induction systems, and has been referred to show no signs of repression when cultivated with lactose concomitantly. In recent research activities, the impact of different products on the lactose uptake using glucose as carbon source was highlighted, and a mechanistic model for glucose-lactose induction systems showed correlations between specific substrate uptake rate for glucose or glycerol (qs,C) and the maximum specific lactose uptake rate (qs,lac,max). In this study, we investigated the mechanistic of glycerol uptake when using the inducer lactose. We were able to show that a product-producing strain has significantly higher inducer uptake rates when being compared to a non-producer strain. Additionally, it was shown that glycerol has beneficial effects on viability of cells and on productivity of the recombinant protein compared to glucose.

Effects of Exercise Induced Dehydration and Glycerol Rehydration on Anaerobic Power in Male Collegiate Wrestlers

McKenna, ZJ and Gillum, TL. Effects of exercise induced dehydration and glycerol rehydration on anaerobic power in male collegiate wrestlers. J Strength Cond Res 31(11): 2965-2968, 2017-Wrestlers attempting to reach a specific weight class often use rapid weight loss (RWL). Rapid weight loss is associated with high levels of dehydration, which may hinder athletic performance. Thus, there is a need for wrestlers to optimize rehydration after achieving a specific weight. We sought to observe the effects of RWL on anaerobic power and the impact of glycerol on rehydration and power in male collegiate wrestlers (n = 7, 19.75 ± 1.67 years, 76.8 ± 4.32 kg, 11.6 ± 4.32% body fat, 59.9 ± 6.42 ml·kg·min). Subjects were assessed for body mass (BM), hydration, and mean power output (Wmean) before exercise (pre), immediately after exercise (3% dehydrated), and 60 minutes after exercise (rehydrated). Participants ran at 70% of V[Combining Dot Above]O2max in a heated room (30° C) until 3% BM loss (BML). Subjects rehydrated drinking either 26 ml·kg of water (control) or a 3% glycerol (treatment) solution containing 26 ml·kg of water and 1 g·kg of glycerol. Participants lost 3.00 ± 0.31% (control) and 2.89 ± 0.26% (treatment) of their BM from the pre- to dehydrated conditions. Wmean (control: 659.29 ± 79.12, 651.43 ± 70.71, 659.71 ± 82.78; treatment: 647.71 ± 110.64, 644.57 ± 118.15, 638.14 ± 100.71) did not differ across time (p = 0.87) nor condition (p = 0.80). In addition, glycerol had no significant impact on acute hydration (control: urine-specific gravity [SG] = 1.019 ± 0.010; treatment: SG = 1.017 ± 0.017). These data show that 3% BML did not impair anaerobic performance, and furthermore that glycerol proved ineffective for rehydration in a match like scenario for the competing wrestler.

Modulation of nonradiative processes of single colloidal quantum dots by glycerol passivation

The radiative and nonradiative processes play predominant roles in the fluorescence performance of single colloidal quantum dots (QDs). In our report, we found that glycerol, a rarely studied chemical for CdSe core–shell QDs, would substantially modulate the nonradiative processes of single QDs. More specifically, the presence of glycerol would passivate the surface traps of single QDs, partly suppressing QD blinking. Simultaneously, glycerol would activate the defect states contributing to the nonradiative pathways, resulting in a shortened fluorescence lifetime and weakened fluorescence intensity. Additionally, glycerol could also stabilize single QDs, rendering enhanced chemical stability and photo stability of single QDs. As far as we know, this is a pioneering work studying on the impact of glycerol on fluorescence properties of CdSe core–shell QDs.

Effect of Glycerol on the Properties of Tapioca Starch Film

Biodegradable films from tapioca starch (TPS) were formed by tape casting. The impact of glycerol (0, 5, 10, 15 and 20%) on the mechanical properties was investigated. The increase in glycerol content reduces the tensile strength while increasing the elongation at break. The varying concentrations of glycerol led to changes in tapioca starch edible film properties, potentially affecting film performances. The merging and increase in the intensity of absorption between 3700-3300 cm-1 as a result of increase in glycerol proportion is due to possible interaction of the OH groups in TPS and glycerol thereby increasing intermolecular H-bond.

Impact of glycerol on Zinc Oxide based thin film transistors with Indium Molybdenum Oxide electrodes

ABSTRACTThin-film transistors (TFT) were fabricated at a room-temperature (RT) with zinc oxide (ZnO) channel and indium molybdenum oxide (IMO) electrodes. To isolate the gate oxide and gate electrode influence on the device performance, common gate configuration on a commercial substrate with thermal SiO2 (100 nm) was selected. A threshold voltage (VTh) of 10 V and ION/IOFF ratio of 1 × 10-5 were obtained. Once the reference data was taken transistors were exposed to glycerol. Temporary changes in device characteristics were observed due to the influence of glycerol, a low conductivity medium. To exclude the possibility of sugar alcohol being the main conductor, measurement on dummy transistor electrode was performed retaining the distance between probes. The TFT device under test revealed ten times higher drain current but also a change in threshold voltage and leakage current. Transistors under glycerol influence were always open with the positive gate bias.

Impact of glycerol and nitrogen concentration on Enterobacter A47 growth and exopolysaccharide production

Enterobacter A47 produces a fucose-containing exopolysaccharide (EPS) by cultivation in mineral medium supplemented with glycerol. EPS synthesis by Enterobacter A47 was shown to be influenced by both the initial glycerol and nitrogen concentrations and by the nutrients’ feeding rate during the fed-batch phase. Initial nitrogen concentrations above 1.05g/L were detrimental for EPS synthesis: the productivity was reduced to 0.35–0.62g/Ld (compared to 1.89–2.04g/Ld under lower nitrogen concentrations) and the polymer had lower fucose content (14–17%mol, compared to 36–38%mol under lower nitrogen concentrations). On the other hand, EPS productivity was improved to 5.66g/Ld by increasing the glycerol and nitrogen feeding rates during the fed-batch phase. However, the EPS thus obtained had lower fucose (26%mol) and higher galactose (34%mol) contents, as well as lower average molecular weight (7.2×105). The ability of Enterobacter A47 to synthesize EPS with different physico-chemical characteristics may be useful for the generation of biopolymers with distinct functional properties suitable for different applications.

Regulatory Role of Glycerol in Candida albicans Biofilm Formation

ABSTRACTBiofilm formation by Candida albicans on medically implanted devices poses a significant clinical challenge. Here, we compared biofilm-associated gene expression in two clinical C. albicans isolates, SC5314 and WO-1, to identify shared gene regulatory responses that may be functionally relevant. Among the 62 genes most highly expressed in biofilms relative to planktonic (suspension-grown) cells, we were able to recover insertion mutations in 25 genes. Twenty mutants had altered biofilm-related properties, including cell substrate adherence, cell-cell signaling, and azole susceptibility. We focused on one of the most highly upregulated genes in our biofilm proles, RHR2, which specifies the glycerol biosynthetic enzyme glycerol-3-phosphatase. Glycerol is 5-fold-more abundant in biofilm cells than in planktonic cells, and an rhr2Δ/Δ strain accumulates 2-fold-less biofilm glycerol than does the wild type. Under in vitro conditions, the rhr2Δ/Δ mutant has reduced biofilm biomass and reduced adherence to silicone. The rhr2Δ/Δ mutant is also severely defective in biofilm formation in vivo in a rat catheter infection model. Expression profiling indicates that the rhr2Δ/Δ mutant has reduced expression of cell surface adhesin genes ALS1, ALS3, and HWP1, as well as many other biofilm-upregulated genes. Reduced adhesin expression may be the cause of the rhr2Δ/Δ mutant biofilm defect, because overexpression of ALS1, ALS3, or HWP1 restores biofilm formation ability to the mutant in vitro and in vivo. Our findings indicate that internal glycerol has a regulatory role in biofilm gene expression and that adhesin genes are among the main functional Rhr2-regulated genes.

The impact of glycerol and some carbohydrates on antibiotic production by Streptomyces hygroscopicus CH-7

The impact of different carbon sources on the antibiotic production by Streptomyces hygroscopicus CH-7 was studied with the main goal to increase the yield of antibiotics hexaene H-85 and elaiophylin. Glucose, as a basic carbon source in the nutrition medium, was replaced with glycerol, xylose, sorbose, melibiose, inulin, and mannitol (15 g/dm3). Insuring the maximum yields of hexaene and elaiophylin of 192 and 88 μg/cm3, respectively, glycerol was shown to be the best carbon source among the investigated ones.

Impact of Glycerol, Mannitol, Neurotol and Neurotol Plus Administration in Alcohol Induced Ischemic Rat Model

Impact of Glycerol, Mannitol, Neurotol and Neurotol Plus Administration in Alcohol Induced Ischemic Rat Model

Five-component food-grade microemulsions: structural characterization by SANS

In this paper we present the structural characterization of a five-component food-grade microemulsion containing Tween 80, R(+)-limonene, ethanol, glycerol, and water. Our main approach to investigating the microstructure of dense microemulsions, and how it can be influenced by the various components, was to employ small-angle neutron scattering and the new evaluation technique for dense, interacting systems, the Generalized Indirect Fourier Transformation. We started our investigation with the impact of glycerol and ethanol on Tween 80 micelles in water. We found that glycerol increases the aggregation number and withdraws the hydrating agents from the headgroup region of the surfactant, resulting in a higher packing density of molecules in a micelle at slightly increasing size. The same trend holds when the micelles are oil swollen and/or ethanol is present. Ethanol, on the other hand, redistributes mainly between water and the interface–headgroup region of the surfactant. Part of it replaces surfactant molecules in the micelles, which increases the available interface and results in a higher number of micelles with shrinking size. The same trend holds when the micelles are oil swollen and/or glycerol is present in the aqueous phase. We also investigated samples along the dilution of a mixture of surfactant and oil phase ( R(+)-limonene and ethanol), which can be diluted with aqueous phase (mixture of water and glycerol) without the occurrence of phase separation. In some samples of this dilution most probably bicontinuous structures are present. To elucidate this point, we also employed dynamic light scattering, viscosity, and conductivity measurements.

Impact of glycerol on thermostability and heat-induced gelation of bovine serum albumin

The influence of glycerol (0–40 wt%) on the thermal denaturation and gelation of bovine serum albumin (BSA) in aqueous solution has been studied. The effect of glycerol on heat denaturation of 0.5 wt% BSA solutions (pH 7.0) was measured using ultrasensitive differential scanning calorimetry. The unfolding process was irreversible and was characterized by a denaturation temperature ( T m). There was no significant change in T m as the glycerol concentration was increased from 0 to 40 wt%, suggesting that glycerol interacted similarly with the native and heat-denatured forms of the protein. The dynamic shear rheology of 4 wt% BSA solutions containing 200 mM NaCl was monitored as they were heated from 30 to 90 °C at 1.5 °C min −1, held at 90 °C for 70 min, and then cooled back to 30 °C at −1.5 °C min −1. The turbidity of the same solutions was monitored as they were heated from 30 to 90 °C at 1.5 °C min −1 or held isothermally at 90 °C for 10 min. Glycerol increased the protein gelation temperature ( ΔT gel ∼+3 ° C for 40 wt% glycerol) and decreased the gelation rate, which was attributed primarily to its ability to decrease the protein–protein collision frequency by increasing solution viscosity. The presence of glycerol either increased or decreased the shear modulus of the gels depending on its concentration and temperature, which was attributed to its ability to alter protein aggregation kinetics during gelation and its ability to increase the attractive forces between proteins at lower temperatures.

Glycerol diversifies phage repertoire selections and lowers non-specific phage absorption

Using a semi-synthetic phage displayed antibody repertoire, isoform-specific and cross-reactive phage-antibodies to eukaryotic elongation factor 1A (eEF1A) have been selected. Enrichment of specific antibodies was found to depend on the presence of glycerol. Further selections against lactate dehydrogenase (LDH) revealed that the dominance of a phage-antibody clone to LDH was inhibited by glycerol, a notable feature for selection strategies where a broad variety of binding clones is desired. The impact of glycerol in distinct steps of the selection protocol was examined and glycerol found to affect certain antibody-antigen interactions. Furthermore, the non-specific phage binding was lowered by three orders of magnitude at a 20% (v/v) glycerol concentration.