Glycerol Concentration Research Articles

Development of Eco-Friendly Biocomposite Films Based on Opuntia ficus-indica Cladodes Powder Blended with Gum Arabic and Xanthan Envisaging Food Packaging Applications.

Currently, food packaging is facing a critical transition period and a major challenge: it must preserve the food products' quality and, at the same time, it must meet the current requirements of the circular economy and the fundamental principles of packaging materials eco-design. Our research presents the development of eco-friendly packaging films based on Opuntia ficus-indica cladodes (OFIC) as renewable resources. OFIC powder (OFICP)-agar, OFICP-agar-gum arabic (GA), and OFICP-agar-xanthan (XG) blend films were eco-friendlily prepared by a solution casting method. The films' properties were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), and differential scanning calorimeter (DSC). Water solubility and moisture content were also determined. Morphology, thickness, molecular interactions, miscibility, crystallinity, and thermal properties, were affected by adjusting the gums (GA and XG) content and glycerol in the blend films. Moisture content increased with increasing glycerol and XG content, and when 1.5 g of GA was added. Water solubility decreased when glycerol was added at 50% and increased with increasing GA and XG content. FTIR and XRD confirmed strong intermolecular interactions between the different blend film compounds, which were reflected in the shifting, appearance, and disappearance of FTIR bands and XRD peaks, indicating excellent miscibility. DSC results revealed a glass transition temperature (Tg) below room temperature for all prepared blend films, indicating that they are flexible and soft at room temperature. The results corroborated that the addition of glycerol at 30% and the GA to the OFICP increased the stability of the film, making it ideal for different food packaging applications.

An experimental investigation on the settling of disk particles in annular region: Wall effect and drag coefficient

Settling non-spherical and spherical particles in the annular region is common in many industrial applications. This work shows the intensification of the performance of settling particles in an annular channel by reducing the drag coefficient. The disk/cylinder particles settle in annular channels filled with Newtonian and non-Newtonian fluids. An aqueous solution of different concentrations of glycerin and Carboxymethylcellulose (CMC) was considered as the Newtonian and non-Newtonian fluids. The experimental results reported in the present work covered the 0.17 ≤ blockage ratio ≤0.55, 0.14 ≤ k (flow consistency index) ≤1.81 (Pa.sn), 0.64 ≤ n (flow behavior index) ≤1, and annular channel Reynolds number 0.40 ≤ Re ≤63.44 and 0.05 ≤ Re ≤43.02 in Newtonian and non-Newtonian fluids respectively. The wall factor, f, was increased with the increase in Re and the decrease in blockage ratio. At higher Reynolds numbers (Re), the particle’s wall factor was only influenced by the blockage ratio. The wall factor was reduced due to the particle’s shape change from cylinder to disk, i.e., decreasing the particle’s sphericity. The wall factor of particles is observed to be higher in non-Newtonian than in Newtonian fluids. The critical Reynolds number (Rec ) decreased with the H/d (Height/diameter of disk) ratio and sphericity of the studied particles. Both the drag coefficients, in the absence ( C D ∞ ) and presence ( C D ) of the wall effect, declined with the Reynolds number. Suitable correlations were developed for CD with low values of RMSLD (root mean square logarithmic deviation). The experimentally obtained drag coefficient data were also analyzed successfully using the laminar model available in Ansys (Fluent) −18.1. The computed velocity contours analyzed the wall effect and CD variations successfully. The use of the annular channel as a drag reduction device is encouraged due to the observed higher wall factor and decreased drag coefficient for particle settling in comparison to the non-annular channel.

Anode Catalysts for Electrocatalytic Alcohol Oxidation Coupled to CO2 Reduction in Continuous-Flow Electrolyzers

Thanks to the intense scientific interest, the field of CO2 electrolysis witnessed remarkable progress (industrially relevant partial current densities, selective electrocatalysts towards small molecule products, multi-cell stacks, etc.) in the past decade. However, despite all these efforts, the energy efficiency of CO2 electrolyzers is still relatively low, which is rooted in the large cell voltages. A reason behind this is that the kinetically sluggish water oxidation (OER) is performed at the anode in parallel with CO2 reduction (CO2RR) at the cathode. This issue can be circumvented by coupling CO2RR with alternative anode processes, resulting in smaller cell voltage (better energy efficiency) along with the possible generation of products at the anode with high market value. Thus, maximizing the potential of utilizing waste carbon sources to generate value-added products. Such alternative reactions include, for example, the electrocatalytic oxidation of chloride ions, aliphatic and aromatic alcohols, amines, urea, hydrazine, and numerous biomass-derived substances such as 5-(hydroxymethyl)furfural, sorbitol, etc.In this study, CO2RR to CO was driven at the cathode, and the electrocatalytic oxidation of glycerol (GOR) was performed at the anode of a small (1 cm2 active surface area) microfluidic electrolyzer cell. Ir black was replaced by carbon-supported Pt nanoparticles, while Ag nanoparticles were used as the cathode catalyst. During our experiments, we identified four main factors influencing the GOR activity and selectivity: i) the quality and quantity of the used ionomer, ii) the electrolyte flow rate, iii) glycerol concentration, and iv) the applied anode potential. The latter was particularly important since Pt showed the highest activity toward GOR in a potential window where its surface starts to oxidize. The formation of a continuous oxide layer has to be avoided since it inhibits the alcohol oxidation reaction. By setting optimal conditions, a close to 100% Faradic efficiency (FE) toward CO formation on the cathode and between 70-80% FE toward GOR was achieved above 200 mA cm-2 total current density. The amount of the formed products were tracked by mass spectrometry, gas-, and high-performance liquid chromatography, and nuclear magnetic resonance spectroscopy. Dihydroxyacetone, glycerate, glycolate, oxalate, tartronate, formate, and lactate were identified as GOR products. The missing charge was attributed to the formation and a small amount of CO2. To improve the stability and selectivity of Pt in GOR, semipermeable metal oxide layers were introduced to the top of the catalyst layer. The thin films were synthesized by electrodeposition in different thicknesses. Based on our measurements, a set of criteria were defined regarding the composition of the anode catalyst layer (ionomer, co-catalyst overlayer, etc.), the composition of the electrolyte solution, and the applied electrochemical protocol to allow stable and selective GOR at high achievable current densities.

Cryo-EM structure of bovine chaperonin TRiC/CCT in open conformation

In this work, conditions were selected for obtaining a sample of eukaryotic chaperonin TRiC suitable for studying by cryo-electron microscopy. Using the method of differential scanning (time-resolved) fluorimetry, the temperature stability of protein samples at different concentrations of salt and glycerol was compared, and then the selected conditions were used to prepare the sample for microscopy. As a result, the structure of bovine TRiC in an open conformation was obtained at 4.42 Å resolution.

FILM MATERIALS BASED ON POLYVINYL ALCOHOL, FILLED WITH SILVER NANOPARTICLES

In the present work polymeric composite films materials based on polyvinyl alcohol (PVA), glycerol and silver nitrate the conducted composites with high mechanical characteristics were created. In the process of composites drying, glycerol acts as a reducing agent and the formation of silver nanoparticles occurs, moreover the reducing take places at room temperature. The AgNO3 content is varied from 0.01 to 30 wt.%. Taking into account the physical-mechanical and conducting properties of composites, it is established that the optimum content of glycerol in the final material is equal to 30 wt%. The formation of metallic silver was confirmed by an appearance of a surface plasmon resonance band at 420-430 nm in UV spectra and the appearance of two diffraction peaks at 38.17° and 44.15° in X-ray diffraction pattern as well, corresponding to the crystallographic planes (111) and (200) of a face centered cubic lattice of Ag0. Dielectric spectroscopy data show that the increasing of glycerol content up to 30-40 wt.% leads to enhance the conductivity by three orders in comparison with the initial PVA. An increase in the silver content resulted in further rise of the conductivity, reaching value of 5.72 10-6 S/cm at 15 wt.% of silver concentration, at room temperature (20 °C). At 100-120 °С, the conductivity was the highest for the composite with 25 wt.% of AgNO3 - 3.67-3.84 10-4 S/cm. The resulting samples had high physical and mechanical properties: relative elongation of about 400%, tensile strength of 32–36 MPa. Studies of the dynamic light scattering of films solution with Ag NPs showed that the smallest size was for the sample with 0.5 wt.% - 6.3 nm.

The strengthening mechanism of mechanical performance for polyurethanes with micro-content crosslinkers

Chemical crosslinking is one widely used method to endow polyurethane (PU) with desirable properties. However, the introduction of crosslinkers in PU elastomers can often lead to the destruction of phase separation, resulting in weakened mechanical properties. Herein, a series of PUs with micro-content crosslinker were synthesized from poly(oxytetramethylene) glycol (PTMG), diphenylmethane-4,4′-diisocyanate (MDI), and chain extender of butane-1,4-diol (BDO) containing varied amounts of glycerol. The phase separation of PUs decreases with increased glycerol content, while the tensile strength increases. To elucidate this enhancement in mechanical properties, morphology investigation with capability of direct observation of components distribution is employed. An increased thickness of interphase between the domain of hard segment (HS) and soft segment (SS) is observed, which indicates that more HS is moved to the interphase upon the introduction of glycerol. The results of electron energy loss spectroscopy (EELS) further disclosed that glycerol formed aggregations located at the interphase. These aggregations increase the crosslinking density of the interphase, which strengthens HS domains and prevents them from being destroyed under tension, thereby increasing the tensile strength. It is the first time of disclosing distribution feature of micro-content crosslinker of PU as well its strengthening mechanism in tensile strength, which could assist in developing PU with desirable mechanical properties.

Beauveria bassiana submerged spores for control of two-spotted spider mite (Tetranychus urticae Koch (Acari: Tetranychidae)): production, stability, and virulence.

In this study, IBCB 66, IBCB 868, and CBMAI 1306 isolates of Beauveria bassiana were grown in liquid culture for 4days, leading to elevated submerged spores (SS) levels. The influence of the addition of different glycerol concentrations (0, 3, and 6%) (v/v) in the liquid culture was investigated regarding the stability (at 4 and 27°C) of dried formulations. The virulence of SS was compared with aerial spores (AS) against Tetranychus urticae (Koch) (Acari: Tetranychidae). The results demonstrate the potential of using SS to control T. urticae. CBMAI 1306 and IBCB 868 isolates caused T. urticae mortality rates of 91.11% and 88.89% 5days after treatment, respectively, when applied at concentrations of 1 × 108 SS mL-1. The median Lethal Time (LT50) values for these strains were 2.64 and 2.61days, respectively. The dried formulations showed potential acaricidal activity. Higher glycerol concentrations in the liquid culture medium reduced formulation stability at 27°C.

DEVELOPING COMPOSITION AND STUDYING PHYSICO-CHEMICAL AND ANTIADHESIVE PROPERTIES OF BIOPOLYMER FILMS BASED ON COLLAGEN AND Na-CMC

The article presents the results of the compatibility of collagen and Na-CMC at various ratios. The study of the structure of the biopolymer composition collagen/Na-CMC/glycerol showed their full compatibility. For the first time, films were obtained from a collagen/Na-CMC/glycerol solution in an aqueous medium, which simplifies the technology for obtaining medicinal films and improves their bioavailability. Using electron microscopy and viscometric studies, the optimal ratio of collagen and Na-CMC 70/30 was chosen, at which materials with strength and viscosity suitable for the formation of a film material were obtained. The optimal concentration of the plasticizer glycerin – 17% – was selected and the physicochemical properties of the films were studied. It has been established that with a decrease in the concentration of glycerol below 17%, the elastic properties of the film deteriorate; an increase in the concentration of more than 17% does not improve the elasticity of the film, but leads to an overuse of the plasticizer. As a result of double plasticization, it is possible to obtain films with good plasticity, which is achieved due to the good compatibility of glycerol with Na-CMC. The microstructure of the films was studied by atomic force microscopy. It has been established that when Na-CMC and glycerol are added to the collagen mass in the established ratios, the uniformity of the films is observed due to the loosening of the collagen microstructure. The biological efficiency of the obtained films was evaluated under the conditions of the development of adhesions in laboratory animals in vivo. The results of the study of anti-adhesion activity indicate the high efficiency of the developed P-3 film for preventing adhesion formation after surgical interventions.

Plant glycerol suppresses brown rot of peach fruit by enhancing disease resistance

Peach fruit is susceptible to fungal contamination during postharvest storage and logistics. Brown rot resulting from Monilinia fructicola infection is one serious disease. Plant glycerol, a natural biodegradable sugar alcohol, can restrain several plant diseases. The inhibitory effect and its mechanism of plant glycerol treatment on brown rot of peach fruit were studied in current study. The findings revealed that 50 mg/g plant glycerol combined with 0.02 % Silwet L-77 surfactant could effectively delay the onset of brown rot caused by M. fructicola. But no concentrations of plant glycerol had significant inhibitory effect on sporangium germination and mycelium growth of M. fructicola. The activities of β-1,3-glucanase (GNS) and chitinase (CHI), the gene relative expression of β-1,3-glucanase (PpGNS), chitinase (PpCHI), pathogenesis-related gene 1 (PpPR1) and nonexpresser of pathogenesis-related gene 1 (PpNPR1) and salicylic acid (SA) content were markedly promoted by plant glycerol treatment. The contents of O2−, H2O2 and oleic acid were significantly repressed, but the activities of superoxide dismutase (SOD) and peroxidase (POD) and the expressions of glycerol kinase 1 (PpGLI1) and glycerol triphosphate dehydrogenase (PpGPDH) were significantly improved. Plant glycerol treatment could induce disease resistance through systemic acquired resistance (SAR) in peach fruit, which might be related to improving the synthesis of polyunsaturated fatty acids. Therefore, plant glycerol treatment is effective on inhibiting brown rot development and possesses potential application in postharvest peach fruit.

PHYSICAL AND THERMAL CHARACTERISTICS OF EXPANDED FOAM GLASSES USING CRUDE GLYCEROL AS A FOAMING AGENT

Expanded foam glasses were fabricated from a clear color soda-lime silicate glass. Crude glycerol was used as an effective foaming agent which promoted small closed cell pores. This research studied the effect of crude glycerol content on the expanding characteristics and thermal properties. The expanding behavior relied on the thermal decomposition mechanism of the foaming agent as well as the sintereing temperature. Expanded foam glasses fabricated at 850°C showed uniform pore size compared to those fabricated at other temperatures (800°C and 900°C). Pore size of the synthesized foam glasses generally increased with increasing firing temperature. The evidence of black color in some areas for samples fabricated at 800°C occurred due to incomplete combustion of crude glycerol within the bulk structure. Samples produced at 850°C and 900°C showed white color shading associated with complete combustion of carbonaceous compound. Foam glasses sintered at 900°C showed structural distortion due to glass melting during the foaming process. Large holes or gaps within the structures occured due to the sweeping and combining of gas bubbles during sintering.

Simultaneous Lipid and Carotenoid Production via Rhodotorula paludigena CM33 Using Crude Glycerol as the Main Substrate: Pilot-Scale Experiments.

Rhodotorula paludigena CM33 is an oleaginous yeast that has been demonstrated to accumulate substantial quantities of intracellular lipids and carotenoids. In this study, crude glycerol, a by-product of biodiesel production, was used as a carbon source to enhance the accumulation of lipids and carotenoids in the cells. The culture conditions were first optimized using response surface methodology, which revealed that the carotenoid concentration and lipid content improved when the concentration of crude glycerol was 40 g/L. Different fermentation conditions were also investigated: batch, repeated-batch, and fed-batch conditions in a 500 L fermenter. For fed-batch fermentation, the maximum concentrations of biomass, lipids, and carotenoids obtained were 46.32 g/L, 37.65%, and 713.80 mg/L, respectively. A chemical-free carotenoid extraction method was also optimized using high-pressure homogenization and a microfluidizer device. The carotenoids were found to be mostly beta-carotene, which was confirmed by HPLC (high pressure liquid chromatography), LC-MS (liquid chromatography-mass spectrometry), and NMR (nuclear magnetic resonance). The results of this study indicate that crude glycerol can be used as a substrate to produce carotenoids, resulting in enhanced value of this biodiesel by-product.

Shaping the chromatic characteristics of red wines by using biofilm-detached cells of Starmerella bacillaris strains

The aim of this study was to evaluate the effects of 10 Starmerella bacillaris strains inoculated as planktonic or biofilm-detached cells on the chromatic characteristics of Montepulciano d’Abruzzo wine. Wines inoculated with biofilm-detached cells of St. bacillaris were characterized by a higher content of glycerol and viable yeast cells and a lower content of ethanol than those obtained with planktonic cells. Pyruvic acid content ranged from 45.99 mg/L to 48.19 mg/L and from 41.13 mg/L to 45.9 mg/L in wines fermented with biofilm-detached and planktonic cells, respectively. Wines obtained with biofilm-detached cells showed levels of anthocyanins ranging from 506.8 mg/L to 659.9 mg/L, while those fermented with free cells of St. bacillaris ranged from 518 mg/L to 612.6 mg/L. Similarly, the content of polyphenols was higher in wines inoculated with biofilm-detached cells. The different amounts of these compounds resulted in differences in the wine's color. Wines obtained with biofilm-detached cells of St. bacillaris had lower b* and h* values than those obtained with planktonic cells. These wines also showed higher a* values, indicating the presence of a stronger red color than the others, and lower clarity (L*). Moreover, the data obtained highlighted that it is possible to predict the color of young wines from must measurements. Further studies will be done to evaluate the role of other non-Saccharomyces yeasts, grown under different aggregation states, in the definition of wine color.

Applying beet peels as a brewing adjunct and its impact on flavour formation

Beer is a complex product, which can use a large diversity of matters as adjuncts. Beet peels (BP) is as a food waste generated from restaurant kitchens/industries. This study investigated the effect of BP as a brewing adjunct on volatile/phenolic compounds, and antioxidant properties of Beer. Worts supplemented with BP were produced using 4 treatments (including a control, B1, B2, and B3). Fermentations were conducted for 11 days at 18 °C, aged for 15 days at 3 °C, and bottled using 7 g of sucrose per bottle. Then maturated for 15 days at 20 °C. Samples were analysed using HPLC (non-volatile compounds), GC-MS (volatile compounds), and antioxidant activity. Increasing the amount of BP during wort preparation revealed a significant increase of volatile profile, phenolic composition, and antioxidant activity. In contrast, was observed a significant decrease in glycerol content. Finally, B2 contained a higher content of acetate esters, hydroxybenzoic/hydroxycinnamic acids and antioxidant activity.

Expression of recombinant human insulin precursor by Pichia pastoris in a 10 liter bioreactor

Recombinant insulin is a vital medicine for diabetic patients. This hormone is produced by microbes such as Pichia pastoris that carry the recombinant gene of a human insulin precursor (HIP). Large-scale protein production involves a bioreactor to promote the optimal condition for the yeast to express the protein target. In order to obtain a large amount of insulin, the cultivation of recombinant P.pastoris/pD902-IP carrying human insulin precursor gene in a bioreactor 10 Liter was developed. The isolate was cultivated in a half concentration of basal salt media for 124.5 hours. Induction of the protein was done by continual methanol feeding. The fermentation condition was set to have a temperature at 28°C, agitation at 300 rpm, aeration at 2 L/min and a pH value of around 5. Dry cell weight (DCW) was measured, and HPLC quantified the content of HIP, glycerol and methanol. This work’s DCW and HIP concentrations were 46.5 g/L and 928 mg/L, respectively. The results can be higher by increasing the number of cells in the culture or extending the cultivation time so that the HIP concentration may exceed 1 g/L.

The Characterization Of Porang Starch (Amorphophallus Oncophyllus) Biodegradable Plastic Using Sorbitol Plasticizer With The Glycerol Plasticizer Addition

This research investigated effect of morphological, mechanical and physical properties on biodegradable plastic made from porang starch with chitosan using, sorbitol plasticizer at concentration 60 and 80 wt%, with the addition of glycerol plasticizer at various concentrations (0%, 25%, 50%, 75%, 100%), made using the melt intercalation method with a gelatinization temperature of 80°C and drying temperature of 70°C. Plasticizer was added to improve flexibility and water absorption of biodegradable plastic properties. Increasing the concentration of the plasticizer resulted in an increase in the elongation of the biodegradable plastic. The biodegradable plastic showed greater tensile strength before addition glycerol plasticizer 1,9191 MPa at 60% concentration and 1,3018 MPa at 80%. Conversely, the addition of 100% glycerol concentration showed an increase in elongation of 77.7764% at 60% sorbitol and 171.0562 at 80% sorbitol. SEM characterization results still showed agglomeration and FTIR not showed any new functional groups. The results of this research indicate that the percentage and kind of plasticizer influence the physical, mechanical, morphological and degradation properties to porang starch biodegradable plastics.

Effect of Glycerol Content in Gelatin/Glycerol Composite Films Loaded with Erythromycin

Effect of Glycerol Content in Gelatin/Glycerol Composite Films Loaded with Erythromycin

Electrochemical properties of a novel EDLC derived from plasticized biopolymer based electrolytes with valuable energy density close to NiMH batteries

This study introduces a novel system of solid electrolytes for electrical double-layer capacitors (EDLCs) utilizing biopolymer electrolytes with high energy density comparable to NiMH batteries. To prepare the electrolytes, a proton-conducting plasticized chitosan: poly(2-oxazoline) (POZ) with good film-forming properties was fabricated using a solution casting technique, and ammonium trifluoromethanesulfonate (NH4CF3SO3) salt was employed as a proton provider. Various glycerol concentrations were incorporated into the chitosan:POZ: NH4CF3SO3 system to enhance the ionic conductivity and fully transparent films were obtained. The impedance technique was utilized to determine the conductivity and measure the diffusion coefficient, mobility, and number density of ions. The electrochemical measurements, including linear sweep voltammetry (LSV) and cyclic voltammetry (CV), validated the high performance of the system. The EDLC was examined using galvanostatic charge-discharge (GCD) equipment, and the results revealed an energy density of 43 Wh/kg, specific capacitance of 300 F/g, and power density of 1800 W/kg over 500 cycles. These findings suggest that it is plausible to develop EDLCs that resemble batteries, making them a more desirable energy storage option for the industry.

Determination of Physical Stability Spray Sunscreen of Extract Wungu Leaf (Graptophyllum pictum (L.) Griff) with Varied Concentrations of Glycerine as A Humectant

Determination of Physical Stability Spray Sunscreen of Extract Wungu Leaf (Graptophyllum pictum (L.) Griff) with Varied Concentrations of Glycerine as A Humectant

Application of the VSP near-infrared fluorescence probe in hyperlipidemia viscosity monitoring

This study introduces a novel near-infrared fluorescent probe named VSP, designed to effectively and sensitively monitor viscosity changes both internally and externally. Through an enhanced conjugation structure of the fluorescent molecule and the incorporation of hydrophilic groups, the VSP probe showcases remarkable sensitivity, selectivity, and stability in its ability to detect viscosity alterations. Notably, the linear correlation between its fluorescence intensity and glycerol content presents the possibility of quantitative viscosity detection, holding significant promise for applications in biomedical research and clinical diagnostics. Moreover, its biocompatibility supports its use for monitoring viscosity within cellular environments. An exceptional attribute is its ability to accurately distinguish between hyperlipidemic model mice and normal mice in animal imaging as well as serum samples, underscoring its potential for early-stage diagnosis of elevated lipid levels and risk assessment for cardiovascular diseases. VSP's potential was demonstrated in cell imaging and differentiation between high-fat and normal mice based on blood serum viscosity. This promising tool holds significant potential for biomedical research and clinical applications in monitoring and analyzing changes in biological systems.

Osmotic Stress Alleviation in Saccharomyces cerevisiae for High Ethanol Fermentations with Different Wort Substrates

High-gravity fermentation, used for ethanol production from sugarcane, corn, and mixed substrates, offers several benefits. Yeast, a rapidly multiplying unicellular microorganism, can be adapted for high sugar and ethanol tolerance on a lab scale. However, different substrates can enhance fermentation efficiency. Our study consisted of two experiments. In the first, we compared simple batch feeding with a fed-batch system for yeast selection in high-gravity fermentation. We ran eight cycles with increasing initial sugar contents (50 to 300 g L−1). No significant differences were observed in the first seven cycles, but in the eighth, the fed-batch system showed lower glycerol and fructose contents and higher cell viability than the simple batch system. In the second experiment, we used the fed-batch system with 300 g L−1 from sugarcane, corn, and mixed wort. The results showed that mixed wort produced higher ethanol contents and greater fermentation efficiency compared to corn and sugarcane as substrates. In conclusion, our findings indicate that the fed-batch system is more suitable for high-gravity fermentation on a lab scale, and the combination of sugarcane juice and corn can enhance fermentation efficiency, paving the way for integrating these substrates in industrial ethanol production.