Treatment Of Glycerol Research Articles

A techno-economic assessment of hydrogen and methane production from the anaerobic treatment of vinasse and glycerol: Single- vs. two-stage process

The best-case scenario for anaerobic digestion (AD) could include co-digestion and two-stage systems, a combination that has not yet been extensively studied. This study aimed at evaluating the effect of increasing the organic loading rate from 5 to 20 kg-COD/m3/d in second-stage thermophilic (55 °C, CH4-RThermo) and mesophilic (25 ± 5 °C, CH4-RMeso) anaerobic fluidized bed reactors (AFBR) fed with sugarcane vinasse and glycerol (1:1 on a COD basis) previously fermented in a thermophilic AFBR. AD was stable with high methane production and COD removal up to 20 kg-COD/m3/d for CH4-RThermo (4.53 L-CH4/L/d; 79 %) and CH4-RMeso (3.85 L-CH4/L/d; 66 %), respectively. At 20 kg-COD/m3/d, CH4-RMeso failed due to acid accumulation (1279 mg/L), which probably inhibited methanogenic activity. Results of two-stage thermophilic + thermophilic (H2-RThermo + CH4-RThermo) were compared with a thermophilic single-stage AFBR. In comparison to the two-stage system, for 10, 15, and 20 kg- COD/m3/d, the single-stage energetic yields were higher at 33, 26 and 22 %, respectively. A techno-economic assessment was conducted. The scale-up and economic analyses revealed that the single-stage would be the most compact system (17,820 vs. 20,560 m3) with the lowest initial investment (USD 45 M vs. USD 52 M), highest net present value (NPV) (USD 58 M vs. USD 47 M), and internal rate of return (IRR) (18 vs. 16 %) compared to the best two-stage system (thermophilic + thermophilic). A Monte Carlo simulation indicated a 12 % risk of financial loss at 20 kg-COD/m3/d for the single-stage system. Furthermore, it showed that variation on the capitalization rate, inflation, and the electricity sales price can significantly affect the NPV. Therefore, in addition to better laboratory performance, the single-stage system is simpler to operate, less costly, and would be more suitable for industrial scale implementation.

Fenton oxidation of glycerin: A sustainable approach for byproduct treatment

This article explores the application of Fenton oxidation as a sustainable and efficient method for the treatment of glycerol, a major byproduct in biodiesel production. Glycerol, rich in impurities, poses environmental challenges if not properly managed. The research aims to contribute to the understanding of Fenton oxidation mechanisms specific to glycerol transformation into dl-glyceraldehyde and to highlight its potential as a sustainable solution. Glycerol, a trihydroxy sugar alcohol, is a versatile compound derived primarily from the hydrolysis of triglycerides and has found applications in various industries, including pharmaceuticals, cosmetics, and food production. One intriguing aspect of glycerol is its potential conversion to dl-glyceraldehyde, a key intermediate with significant importance in various biological processes. Employing Fenton oxidation emerges as beneficial approach in glycerol processing, considering the tenets of environmental sustainability.

Glycerol-mediated lysosomal associated proteins as a novel anticancer theory in colon cancer cell line

Background: Colon cancer begins in the large intestine (colon) and is aggressive due to late diagnosis, so there is a poor prognosis and higher mortality rates, as reported. Colon cancer has become a vital research area requiring more investigation of cellular signaling in its initiation and development. Aim: The study aimed to investigate the biological effects of Glycerol in cell proliferation and the possible regulation of cellular signaling by exogenous treatment of Glycerol in colon cancer cells compared with colon mucosal epithelial cells. 
 Materials and Methods: The influence of Glycerol on cell viability rate was monitored by inverted microscopy, and the number of living cells was assessed upon incubation with different concentrations of Glycerol. We further inspected the apoptotic rate of CaCo-2 cells by using Annexin-V staining by flow cytometry. Moreover, we achieved the expression profile of lysosomal-associated proteins, LAMP-1 and LAMP-2, in treated cells using qRT-PCR and flow cytometry. Finally, we monitored the released pro-inflammatory cytokines and anti-inflammatory in response to Glycerol treatment using ELISA assay. 
 Results: Our results showed that Glycerol treatment could prevent cancer cell proliferation without any detectable cytotoxic occurrence in the normal cells. Interestingly, we evidenced that Glycerol targets and breaks down the lysosomal activities by inhibiting the expression profile of both LAMP-1 and LAMP-2. Furthermore, Glycerol treatment successfully adjusted the production of IL-6 and IL-8 as pro-inflammatory cytokines while stimulating the production of anti-inflammatory cytokines, IL-4 and IL-10, in a time-dependent manner. 
 Conclusion: These data provide evidence for the anti-cancer properties of Glycerol in colon cancer cells via targeting lysosomal activities and disturbance of the degradation events in colon cancer cells. 

Polyhydroxybutyrate production from crude glycerol using a highly robust bacterial strain Halomonas sp. YLGW01

Petrochemical-based plastics are hardly biodegradable and a major cause of environmental pollution, and polyhydroxybutyrate (PHB) is attracting attention as an alternative due to its similar properties. However, the cost of PHB production is high and is considered the greatest challenge for its industrialization. Here, crude glycerol was used as a carbon source for more efficient PHB production. Among the 18 strains investigated, Halomonas taeanenisis YLGW01 was selected for PHB production due to its salt tolerance and high glycerol consumption rate. Furthermore, this strain can produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3 HV)) with 17 % 3 HV mol fraction when a precursor is added. PHB production was maximized through medium optimization and activated carbon treatment of crude glycerol, resulting in 10.5 g/L of PHB with 60 % PHB content in fed-batch fermentation. Physical properties of the produced PHB were analyzed, i.e., weight average molecular weight (6.8 × 105), number average molecular weight (4.4 × 105), and the polydispersity index (1.53). In the universal testing machine analysis, the extracted intracellular PHB showed a decrease in Young's modulus, an increase in Elongation at break, greater flexibility than authentic film, and decreased brittleness. This study confirmed that YLGW01 is a promising strain for industrial PHB production using crude glycerol.

Effect of selenate on treatment of glycerol containing wastewater in UASB reactors

The effect of selenate on the removal of glycerol in up-flow anaerobic sludge blanket (UASB) reactors was investigated. Two UASB reactors, RControl and RSelenium, were operated at a hydraulic retention time of 48 h and an upflow velocity of 2 m/h at 37 °C. A GAL (glucose, acetate and lactate) and glycerol mixture were used as the only feedstock throughout the experiment for RControl. After acclimation to GAL and glycerol in the start-up period, RSelenium was additionally exposed to selenate (SeO42−) concentrations from 1.43 to 71.49 mg/L (10–500 μM) in a stepwise manner. An average daily methane yield of about 150 mL/g COD, which was comparable with RControl, and 90% Se removal were achieved until 400 μM SeO42−. Simultaneously, SeO42− was reduced to elemental Se or metal selenide, supported by X-ray diffraction, as well as scanning and transmission electron microscopy. However, the methane production rapidly deteriorated when the influent SeO42− concentration was increased to 500 μM. The Se toxicity was evident from the reduction in the activity of Methanosaeta. This study showed that the SeO42− concentration, but not the COD/SeO42− ratio, governs the AD of selenate rich wastewaters.

Increasing the surface hydrophobicity of silicone rubber by electron beam irradiation in the presence of a glycerol layer

A cost-effective and scalable silicone rubber (SR) modification technology for increasing its surface hydrophobicity is urgently needed to enhance the stability of global power systems. In this work, an easily accessible method was developed to increase the surface hydrophobicity of silicone rubber, which was established by high-energy electron beam irradiation in the presence of a layer of glycerol. Although glycerol is a highly hydrophilic alcohol, the contact angle of silicone rubber can be surprisingly increased by 19.9% with the irradiation treatment of glycerol. Despite a high hydroxyl content being observed, a network structure formed on the silicone rubber surface is responsible for the increase in hydrophobicity. Control experiments and molecular dynamics (MD) simulations were also conducted to shed light on the underlying mechanism. This method has some intrinsic advantages, such as cost-effectiveness, easy operation and nontoxicity of glycerol; thus, it is expected to be applicable in large-scale industrial production and modification of silicone rubber.

Effect of Selenate on Treatment of Glycerol Containing Wastewater in Uasb Reactors

Effect of Selenate on Treatment of Glycerol Containing Wastewater in Uasb Reactors

Biodiesel production from microbial lipid obtained by intermittent feeding of municipal sludge and treated crude glycerol

In the present study, municipal secondary sludge and purified glycerol (obtained after acid treatment of crude glycerol) were used together for lipid production using intermittent feeding strategy. Intermittent sludge feeding strategy (sludge SS 30 g/L) resulted in a higher biomass (54.99 g/L) and lipid concentration (25.35 g/L) at 96 h when compared to 35 g/L SS single sludge feeding or control strategy (45.67 g/L biomass & 19.16 g/L lipid). Moreover, the intermittent sludge feeding strategy significantly reduced foaming and requirement of anti-foam during fermentation when compared to control strategy. The energy balance of biodiesel production from lipid obtained by intermittent sludge feeding strategy (30 g/L SS) was energetically favorable. It was also revealed from yield coefficients and energy balance that sludge had an important contribution in microbial lipid and biodiesel production.

Physical Mechanical Properties of Biodegradable Plastics from Cassava Starch with Variation of Bagasse and Glycerol.

Environmental problems are related to plastic waste that difficult to degrade naturally. Polysaccharides in the form of gelatinized cassava starch and bagasse containing 52.70% cellulose can replace commercial plastic polymers. This research was aimed to determine the effect of variations in bagasse and glycerol on physical, mechanical and biodegradation tests. The study used 2 factors CRD consisting of the addition of bagasse and glycerol. The results showed that the addition of bagasse and glycerol reducing the brightness with a value range of 44.82-76.15 and increased absorption between 2.61-10.64%. The thickness occurred between 0.79-1.11mm. The tensile strength values are 8.30-14.33 MPa, inversely proportional to the elongation value between 11.85-94.22%, but directly proportional to the modulus young value between 0.09-1.24 MPa. The highest biodegradation values were 0% bagasse and 40% glycerol. The three best treatments were found in the combination treatment of bagasse and glycerol 0% 20%, 0% 30%, and 0% 40%.

Bifunctional copper cathode induced oxidation of glycerol with liquid plasma discharge

Treatment of glycerol, the byproduct from biodiesel production, calls for a more efficient and cost-effective approach. In this work, in situ hybrid induced oxidation method was proposed, involving the advanced oxidation process and electro-catalytic process. Generally, these highly active species in the plasma region is helpful to degrade the organic products. In addition, numerous CuO nanoparticles with oxygen defects that were induced by the plasma, could improve the catalytic performances. In the plasma discharge process, those CuO catalysts and plenty of hydrogen bubbles which were generated around the copper cathode, also resulted in the high efficiency dehydration of glycerol. The effects of discharge status of liquid plasma and glycerol volume on conversion rate were discussed in detail. It was found that a lower discharge voltage 70 V in the normal glow discharge period is beneficial to dehydration of glycerol. Combined with the FTIR analysis for products composition, the degradation products and the conversion rate were illustrated using the HPLC. The experimental results showed it can achieve a conversion rate of 81.27% after 40 min and the energy yield was 10.02 g/(kW h).

Treatment of industrial glycerol from biodiesel production by adsorption operation: kinetics and thermodynamics analyses

Equilibrium, thermodynamic, and kinetic analyses of the pigments adsorption of the industrial glycerol onto activated charcoal were performed. As the pigments concentration was not known, then, a relative adsorption capacity was defined using absorbance values measured in a spectrophotometer at a wavelength of 265 nm. Kinetic study showed that about 60 s were needed to reach equilibrium conditions. Relative adsorption capacity reached 8 g−1 for 1% of adsorbent amount (w/w). Adsorption enthalpy was of –17.63 kJ mol−1, while for isosteric heat values were obtained between –7.39 and –18.46 kJ mol−1. The mathematical methodology used for the parameters determinations proved to be robust and able to express the relationships of kinetics, equilibrium and thermodynamics. Enthalpy values obtained by Van't Hoff method was confirmed by isosteric heat calculation, evidencing that this methodology can be used for systems whose compositions are unknown, but detectable by indirect form.

Production of succinate from simply purified crude glycerol by engineered Escherichia coli using two-stage fermentation

BackgroundCrude glycerol is a main by-product from biodiesel production, and efficient utilization of crude glycerol will bring significant economic and environmental benefits. However, the complex compositions of crude glycerol may impair the cellular growth and inhibit the crude glycerol consumption. Therefore, it is necessary to find a simple method to treat the crude glycerol and release the inhibition on cell metabolism.ResultsThe simply purified crude glycerol by activated carbon can be used as the carbon source to produce succinate in two-stage fermentation by the engineered Escherichia coli strain, MLB (ldhA−, pflB−) expressing phosphoenolpyruvate carboxykinase. In the flask experiments, succinate production from crude glycerol without treatment was less than that from pure glycerol. However, in the experiments of 1.5-L bioreactor, little succinate was produced in crude glycerol. The simply purified crude glycerol was used as carbon source for succinate production, and the glycerol consumption and succinate production were enhanced greatly. The succinate produced from the simply purified crude glycerol reached 566.0 mM, which was about ten times higher as that of non-purified one (50.3 mM). The succinate yield of the anaerobic stage achieved 0.97 mol/mol, which was 97% of the theoretical yield.ConclusionThe treatment of crude glycerol by activated carbon could effectively release the inhibition on the glycerol consumption and succinate production of the engineered E. coli strains, so that the fermentation result of the treated crude glycerol was similar as the pure glycerol. The results showed that the metabolically engineered E. coli strains have great potential to produce succinate from crude glycerol.

On-off-on fluorescent nanosensor for Fe3+ detection and cancer/normal cell differentiation via silicon-doped carbon quantum dots

In this study, an on-off-on fluorescent nanosensor based on carbon quantum dots (or carbon dots, CDs) was successfully fabricated for Fe3+ detection and selective imaging of cancerous cells in vitro and in vivo. The multifunctional CDs were prepared by a one-pot solvothermal treatment of glycerol and a silane molecule (N-[3-(trimethoxysilyl)propyl]ethylenediamine, DAMO). The as-prepared CDs exhibited excellent fluorescence (FL) properties and favorable biocompatibility, and could realize wash-free cell imaging both in vitro (e.g., for bacterial and fungal cells) and in vivo (e.g., for zebrafish embryos). On the other hand, the fluorescence of CDs can respond to Fe3+ selectively and sensitively, with a very low detection limit of 16 nM. Besides, detection of Fe3+ in living cells and zebrafish was also successfully realized by the CDs. Moreover, it was found that glutathione (GSH) could enhance the fluorescence of the mixed solution of CDs and Fe3+ (CDs/Fe3+), and such a property could be utilized to efficiently distinguish cancerous cells from normal ones based on the difference in the content of GSH of the two types of cells. More importantly, GSH also realized the enhanced fluorescence signals of CDs/Fe3+ in tumor site in vivo after intravenous injection, indicating the potential of CDs/Fe3+ for imaging-guided precision cancer diagnosis.

TIME, ENERGY EFFICIENCY IN THE PRODUCTION OF BIODIESEL, AND PRODUCTS DESTINATION IN A BIOREFINERY

This manuscript deals with the production of biodiesel from triglycerides (TG); soybean oil was the primary raw material. The transesterification reaction was used to convert triglycerides into monoalkyl esters. The catalytic mixture of methanol and potassium hydroxide (KOH) was used in the transesterification reaction. The anhydrous refining of biodiesel was used to reduce side reactions during the purification process. The treatment of glycerol by acidification with H3PO4 and its subsequent purification was a convenience process aiming to form the desired byproducts. The conversion of residual fatty acids to soaps through the saponification reaction or into esters through the esterification reaction with H2SO4 can be done by observing the market of those products. The monitoring of the transesterification reaction in real-time with laser spectroscopy allows the variation of the temperature during the reaction process without losing the reaction endpoint. The use of only one reaction vessel for the accomplishment of several unit operations aiming the reducing of the reaction time in the production process was well succeeded. The main resulting products are biodiesel, glycerol, fertilizer, and soaps. As expected the biodiesel can be used as a source of energy, the glycerol can be further refined but this process was not explored at this manuscript, the resulting salts can be used as fertilizers, and the soups can be sold and used as a soup.

Production of gamma‐aminobutyric acid by Escherichia coli using glycerol as a sole carbon source

AbstractBACKGROUNDIn the biodiesel industry, crude glycerol is produced in huge quantities as a by‐product, and therefore, the economic conversion of crude glycerol into a value‐added product is a priority. One possible way of achieving such a conversion is to feed glycerol to Escherichia coli cells so that they can grow and produce valuable products such as gamma‐aminobutyric acid (GABA) at the same time.RESULTSFour E. coli strains were compared for their growth rates and GABA production using glycerol as sole carbon source. GABA production was associated with cell growth by constitutively expressed mutant glutamate decarboxylase that exhibited activity at neutral pH. Simple treatment of crude glycerol with phosphoric acid resulted in a fermentable grade of glycerol, and the superb strain, W, converted 2.0 g L−1 of crude glycerol into 0.15 g L−1 of GABA in 12 h in a batch culture. In a fed‐batch type culture with pH titration, the strain W converted overall 15 g L−1 of crude glycerol into 0.98 g L−1 of GABA in 36 h.CONCLUSIONIt is possible to convert crude glycerol into GABA in a growth‐associated manner using E. coli W, and the strain will serve as a base strain for future metabolic engineering approaches. © 2017 Society of Chemical Industry

Mitochondria-targetable carbon quantum dots for differentiating cancerous cells from normal cells.

In this study, a series of fluorescent carbon quantum dots (or carbon dots, CDs) with inherent mitochondrial targeting/imaging and cancerous/normal cell differentiation capabilities were prepared by a one-pot solvothermal treatment of glycerol and a silane molecule. Glycerol acted as a solvent and carbon source, and the silane molecule acted as a passivation agent. The as-prepared CDs could specifically and stably (for at least 24 h) visualize mitochondria of various types of cells without the introduction of mitochondria-targeting ligands (such as triphenylphosphonium). In addition, the CDs exhibited extraordinary features including facile synthesis, good water solubility, favorable biocompatibility, and excellent photostability as compared to commercial mitochondrial probes. Moreover, the CDs could efficiently distinguish cancerous cells from normal cells with high fluorescence contrast due to differences in their mitochondrial membrane potentials and substance uptake efficiencies. More importantly, to the best of our knowledge, the present study provides the first example of using CDs to distinguish cancerous cells from normal cells. The remarkable features of mitochondria-targeted imaging and cancerous cell recognition make the CDs an excellent fluorescent probe for various biomedical applications.

Methanol formation from the treatment of glycerol in supercritical water and with ethylsulfide

Methanol is found to be a major product when glycerol decomposes under supercritical water conditions. Glycerol is a significant byproduct of biodiesel waste streams, the value of which is decreasing as biodiesel output increases. The transformation of glycerol into methanol, which is a feedstock for biodiesel production, would potentially reduce the costs and climate impact of biodiesel production. The highest yield of methanol was found at 450°C, 300bar after 30min residence time. Addition of ethylsulfide increases the rate but does not improve the methanol yield. At longer residence times, methanol and acetaldehyde were consumed and acetic acid was produced. The generation of significant quantities of methanol (non-catalytically) from glycerol was not previously observed, and thus no mechanism for methanol production had been proposed in the published literature. A detailed kinetic model for the glycerol plus supercritical water system was constructed using the Reaction Mechanism Generator (RMG) software package. All the parameter values in this large model were predicted a priori based on quantum chemistry calculations; none were adjusted to try to match our data, which serves as a test set for the model predictions. The a priori kinetic model predicts yields of acrolein, acetic acid and acetaldehyde similar to those measured by previous researchers. However, the model underpredicted the yield of methanol measured in our experiments. We speculate that the generation of higher concentrations of methanol in our experiments than in prior work might be due to catalytic reactions on the reactor walls, since our reactor has different metallurgy than those used in prior studies.

Changes in the microbial community during the acclimation stages of the methane fermentation for the treatment of glycerol

Granular sludge from a full-scale methane reactor treating brewery wastewater was used as a seed for the treatment of glycerol in a laboratory-scale repeated-batch methane reactor, and the change in the microbial community during the acclimation stages was examined. Two types of substrate solutions, a glucose, sodium acetate, and lactic acid mixture, as well as glycerol, were prepared and fed by mixing the two solutions to increase the ratio, in a stepwise manner, of glycerol from 0% to 100%, while keeping a loading of COD at 2.5 kg m−3 d−1 throughout the fermentation process. Vigorous methane gas production, approximately 580 dm3 m−3 d−1, was observed during the acclimation stages. Microbial analysis revealed that both bacterial and archaeal communities changed significantly; bacteria (genus Trichococcus and family Syntrophomonadaceae) became dominant rapidly after the start of acclimation, and archaea belonging to the hydrogenotrophic methanogens (genera Methanobacterium and Methanospirillum), increased gradually with the progress of acclimation.

Metabolic Capabilities of the Members of the Order Halanaerobiales and Their Potential Biotechnological Applications

The order Halanaerobiales contains a number of well-studied halophiles that possess great potential for biotechnological applications. The unique halophilic adaptations that these organisms utilize, such as “salting-in” mechanisms to increase their intercellular concentration of KCl, combined with their ability to ferment simple sugars, provides an excellent platform for biotechnological development over a wide range of salt levels and possible other extreme conditions, such as alkaline conditions. From fermented foods to oil reservoirs, members of Halanaerobiales are found in many environments. The environmental conditions many of these organisms grow are similar to industrially important processes, such as alkaline pre-treated biomass stocks, treatment of crude glycerol from biodiesel production, salty fermented foods, as well as bioremediation of contaminants under extreme conditions of salinity and in some cases, alkalinity. From salt-stable enzymes to waste fermentations, bioremediation options, bioenergy, and microbially enhanced oil recovery (MEOR), Halanaerobiales can provide a wide spectrum of environmentally friendly solutions to current problems. Keywords: Bioenergy, bioremediation, fermented foods, Halanaerobiales, halophilic hydrolases, MEOR.

Mitigation of the inhibitory effect of soap by magnesium salt treatment of crude glycerol – A novel approach for enhanced biohydrogen production from the biodiesel industry waste

Owing to its inhibitory effect on microbial growth, soap present in crude glycerol (CG) is a concern in biological valorization of the biodiesel manufacturing waste. By salting out strategy, up to 42% of the soap has been removed and the approach has beneficial effect on H2 production; however, removal of more than 7% of the soap was found to be inhibitory. Actually, soap is utilized as a co-substrate and due to removal; the carbon-nitrogen ratio of the medium might have decreased to reduce the production. Alternatively, without changing the carbon-nitrogen ratio of CG, MgSO4 treatment can convert the soap to its inactive form (scum). The approach was found to increase the H2 production rate (33.82%), cumulative H2 production (34.70%) as well as glycerol utilization (nearly 2.5-folds). Additionally, the treatment can increase the Mg (a nutrient) content of the medium from 0.57 ppm to 201.92 ppm.