Residual Triglyceride Research Articles

Normal plasma apoB48 despite the virtual absence of apoB100 in a compound heterozygote with novel mutations in the MTTP gene

“Normotriglyceridemic abetalipoproteinemia (ABL)” was originally described as a clinical entity distinct from either ABL or hypobetalipoproteinemia. Subsequent studies identified mutations in APOB gene which encoded truncated apoB longer than apoB48. Therefore, “Normotriglyceridemic ABL” can be a subtype of homozygous familial hypobetalipoproteinemia. Here, we report an atypical female case of ABL who was initially diagnosed with “normotriglyceridemic ABL”, because she had normal plasma apoB48 despite the virtual absence of apoB100 and low plasma TG level. Next generation sequencing revealed that she was a compound heterozygote of two novel MTTP mutations: nonsense (p.Q272X) and missense (p.G709R). We speculate that p.G709R might confer residual triglyceride transfer activity of MTTP preferentially in the intestinal epithelium to the hepatocytes, allowing production of apoB48. Together, “normotriglyceridemic ABL” may be a heterogenous disorder which is caused by specific mutations in either APOB or MTTP gene.

Enzymatic Methods for the Manipulation and Valorization of Soapstock from Vegetable Oil Refining Processes

The review will discuss the methods that have been optimized so far for the enzymatic hydrolysis of soapstock into enriched mixtures of free fatty acids, in order to offer a sustainable alternative to the procedure which is currently employed at the industrial level for converting soapstock into the by-product known as acid oil (or olein, i.e., free fatty acids removed from raw vegetable oil, dissolved in residual triglycerides). The further biocatalyzed manipulation of soapstock or of the corresponding acid oil for the production of biodiesel and fine chemicals (surfactants, plasticizers, and additives) will be described, with specific attention given to processes performed in continuous flow mode. The valorization of soapstock as carbon source in industrial lipase production will be also considered.

Sequential extraction and reactive extraction processing of spent coffee grounds: An alternative approach for pretreatment of biodiesel feedstocks and biodiesel production

An alternative approach to producing biodiesel from spent coffee grounds (SCGs) has been developed with methanol washing applied as a pretreatment step, followed by in-situ transesterification. Under optimal conditions, methanol washing was able to reduce the high acid value of SCGs to 0.78 mg KOH g−1 with a negligible loss of their oil content, which ended up being 11.43% by mass. Pretreated SCGs were then directly treated with a potassium methoxide solution and isopropanol as co-solvents in the in-situ transesterification process. A central composited rotatable design was applied to determine the optimal conditions for KOH concentration and proportion of isopropanol. The results showed that both KOH concentration and proportion of isopropanol had significant effects on the biodiesel yields, residual triglyceride in the biodiesel, and extraction performance (p-value <0.05). The optimal conditions were provided by KOH concentration of 2.5 g in a 100 mL mixture of methanol and 25% volume of isopropanol, using 2.7 mL of the reagent to 1 g of SCGs at 30 °C for 2 h. Under these conditions, 88.8% biodiesel yield (i.e., 102 mg of biodiesel per 1 g of SCGs), with a less than 0.1% mass of residual triglycerides in the biodiesel, was achieved.

Hybrid Processes for Extraction–separation of Tocopherols from Crude Palm Oil

The aim of this study was to evaluate the hybrid processes for extraction and separation of tocopherols from crude palm oil. The saponification method was used to extract crude palm oil under various concentrations of alcoholic KOH in the range of 10–60% w/v in a lab scale unit. The experiments were conducted at a temperature and saponification time in the range of 60–80°C and 20–40 min respectively. The performance and efficiency of ultrafiltration were investigated by filtering a fraction of unsponifiables. The results showed that the optimum condition of saponification was 10% alcoholic KOH with the minimum loss of α–tocopherol of around 19%. A lab scale filtration unit with a hydrophobic sheet membrane was operated under a frontal filtration mode at room temperature. The results pointed out that ultrafiltration could remove most of the residual triglycerides and phospholipids contained in unsponifiables at a TMP of 0.25–1.0 bars. The removal of up to 70% of triglycerides and phospholipids was reached when the mixture was ultrafiltered. In addition, these hydride processes present a one of the great option for α–tocopherol purification losing about 5% of yield.

Improving the yield of Jatropha curcas's FAME through sol–gel derived meso-porous hydrotalcites

The conversion of fatty acid methyl ester (FAME) from triglycerides using heterogeneous catalysis has gained increasing interest due to the prospect of increased yield at reduced operating costs and reaction conditions. In this paper, meso-porous hydrotalcite was used to catalyze jatropha oil into FAME with relatively higher yield at atmospheric pressure and relatively low reaction temperature. The molar ratio of methanol to oil required was relatively low and the conversion was completed within few hours of reaction time. The reaction was promoted when moderate calcination temperature was applied, the disordered structure of the catalyst was maintained, counterbalance anions was removed, and phase transitions within the oxide lattice was induced. Despite the observed deactivation during successive reaction cycles due to adsorption of residual triglycerides, the catalyst performance was restored effectively by air-re-calcination.

Physiological assessment of the effects of changing water levels associated with reservoir management on fattening rates of neotropical migrants at a stopover site.

Riparian habitat makes up a small fraction of the landscape but provides important stopover habitat for migratory birds. Hydroelectric dam operations cause fluctuations in water levels that can change the amount or quality of riparian habitat, which in turn might affect potential fattening rates of migrant birds. Here we used plasma metabolite analysis to estimate variation in fattening rate in relationship to variable water levels associated with reservoir management in four species of neotropical migratory songbirds using riparian habitat at a dam-impacted stopover site in Revelstoke, British Columbia, Canada. Residual plasma triglyceride, our measure of estimated fattening rate, varied systematically with time of day and Julian date and varied consistently among species, but did not vary with age or sex. Controlling for potentially confounding variables, we found no inter-annual variation in estimated fattening rate, even though there were marked differences in water levels among years. Likewise, there was no relationship between daily variation in water levels and estimated fattening rate. Data on feather isotopes (δD), indicative of migratory origin, did not add explanatory power to our models. There was inter-annual variation in plasma glycerol and β-hydroxybutyrate levels and significant, though weak, relationships between these metabolites and water level (higher metabolite levels when drier) that might indicate effects on 'body condition' independent of fattening rate. Our study suggests that, at present, although hydroelectric dam operations influence water levels in the Arrows Lake Reservoir and adjacent riparian habitats, this does not significantly impact fattening rates of migratory passerines using these habitats.

The peculiarities of succinic acid production from rapeseed oil by Yarrowia lipolytica yeast

The process of succinic acid (SA) production represents the combination of microbial synthesis of α-ketoglutaric acid from rapeseed oil by yeast Yarrowia lipolytica VKM Y-2412 and subsequent decarboxylation of α-ketoglutaric acid by hydrogen peroxide to SA that leads to the production of 69.0gl(-1) of SA and 1.36gl(-1) of acetic acid. SA was isolated from the culture broth filtrate in a crystalline form. The SA recovery from the culture filtrate has certain difficulties due to the presence of residual triglycerides of rapeseed oil. The effect of different methods of the culture filtrate treatment and various sorption materials on the coagulation of triglycerides was studied, and as a result, the precipitation of residual triglycerides by acetone was chosen. The subsequent isolation procedures involved the decomposition of H2O2 in the filtrate followed by filtrate bleaching and acidification with a mineral acid, evaporation of filtrate, and SA extraction with ethanol from the residue. The purity of crystalline SA isolated from the culture broth filtrate achieved 97.6-100%. The product yield varied from 62.6 to 71.6% depending on the acidity of the supernatant.

Enhanced α-ketoglutaric acid production and recovery in Yarrowia lipolytica yeast by effective pH controlling

The replacement of chemical synthesis by environmentally friendly energy-efficient technologies for production of valuable metabolites is a principal strategy of developing biotechnological industry all over the world. In the present study, we develop a method for α-ketoglutaric acid (KGA) production from rapeseed oil with the use of Yarrowia lipolytica yeast. Sixty strains of Y. lipolytica yeasts were tested for their ability to produce KGA, and the strain Y. lipolytica 212 (Y. lipolytica VKM Y-2412) was selected as a promising KGA producer. Using a three-stage pH controlling, in which pH was 4.5 in the growth phase, then since 72 to 144h, pH was maintained at 3.5 and in the later phase of acid production, the titration by KOH was switch off, selected strain produced 106.5gl(-1) of KGA with mass yield of 0.95gg(-1). KGA in the form of monopotassium salt was isolated from the culture broth and purified. The isolation procedure involved separation of biomass, extraction of residual triglycerides, filtrate bleaching, and acidification with mineral acid (to pH2.8-3.4), concentration, precipitation of mineral salts, and crystallization of the product. The purity of KGA isolated from the culture filtrate reached 99.1%.

Elevational differences in estimated fattening rates suggest that high-elevation sites are high-quality habitats for fall migrants

ABSTRACT. Many migrant songbird species use high-elevation habitats for stopovers in fall throughout North America, but whether these are good migration habitats as indicated by high fueling rates or other measures has not been previously quantified. At high-quality stopover sites, birds can refuel while maintaining their optimal or preferred migration schedules. We used plasma metabolite analysis to estimate fueling rates of four songbird species during the fall migration period over 3 years at two high-elevation (1,200 m above sea level) and two low-elevation (<25 m above sea level) sites in southwestern British Columbia. For three species with more frugivorous diets during fall—the Fox Sparrow (Passerella iliaca), Golden-crowned Sparrow (Zonotrichia atricapilla), and Hermit Thrush (Catharus guttatus)—estimated fattening rates (defined as residual plasma triglyceride levels) were 37–65% higher at high-elevation sites than at low-elevation sites. By contrast, the largely insectivorous and smaller-bodied ...

Enzymatic production of biodiesel from waste cooking oil in a packed-bed reactor: An engineering approach to separation of hydrophilic impurities

An engineering approach was applied to an efficient biodiesel production from waste cooking oil. In this work, an enzymatic packed-bed reactor (PBR) was integrated with a glycerol-separating system and used successfully for methanolysis, yielding a methyl ester content of 94.3% and glycerol removal of 99.7%. In the glycerol-separating system with enhanced retention time, the effluent contained lesser amounts of glycerol and methanol than those in the unmodified system, suggesting its promising ability to remove hydrophilic impurities from the oil layer. The PBR system was also applied to oils with high acid values, in which fatty acids could be esterified and the large amount of water was extracted using the glycerol-separating system. The long-term operation demonstrated the high lipase stability affording less than 0.2% residual triglyceride in 22 batches. Therefore, the PBR system, which facilitates the separation of hydrophilic impurities, is applicable to the enzymatic biodiesel production from waste cooking oil.

Continuous production of fatty acid ethyl esters from soybean oil at supercritical conditions

This work reports the production of fatty acid ethyl esters (FAEE) from the transesterification of soybean oil in supercritical ethanol in a continuous catalyst-free process using different reactor configurations. Experiments were performed in a tubular reactor in one-step reaction and experimentally simulating two reactors, one operated in series and the other a recycle reactor. The reaction products were analyzed for their content of residual triglycerides, glycerol, monoglycerides, diglycerides, ethyl esters and decomposition. Results show that the configurations studied with intermediate separation of glycerol afford higher conversions of vegetable oil to their fatty acid ethyl esters derivatives when compared to the one-step reaction, with relatively low decomposition of fatty acids (< 5.0 wt%).

Refined soybean oil transesterification enhanced by sonication

Biofuels are of great topical interest, especially in the light of recent European directives. Biodiesel is both already available and thoroughly regulated. A critical aspect of the transesterification process, used in biodiesel production, is maximization of the contact surface between reagents. This is currently achieved using discontinuous processes with mechanical agitation, which however afford poor mixing efficiency. Ultrasound appears to be an effective method to enhance mixing intensity. The aim of this work was to assess the advantages offered by this technique, especially in terms of process velocity. For this purpose a small scale experimental apparatus for biodiesel production integrated with a modular ultrasound system was set up. Plant dimension and energy inputs were chosen to enable eventual industrial implementation. Plant performances were assessed as the velocity of oil conversion to fatty acids methyl esters. The product was analyzed according to EN 14105. In general, the efficiency of ultrasound in increasing reaction velocity was markedly affected by residual triglyceride content. Conversion rates in line with EN 14214 and ASTM D6751 standard specifications, which allow a maximum residual triglycerides content of 0.20%, were obtained with reductions in reaction time of about 20%. In less stringent conversion conditions, e.g. 3% triglycerides, the reaction time was roughly halved. Below 1% of triglycerides residues sonication should be interrupted and the process continued with conventional agitation.

Preparation and characterization of gelatin sponge millispheres from air-in-water-in-oil-type emulsions

A novel method for the preparation of gelatin sponge millispheres (GSMs) for biomaterials such as embolic agents and cell scaffolds was developed using an air-in-water-in-oil-type emulsion. The droplets, consisting of a foamy gelatin suspension in caprylic triglyceride, were gelled and rinsed with isopropanol. Sonication and depressurization were used during the rinsing process to create interconnected pores. GSMs cross-links created over 4 h at 155 degrees C without any agent were insoluble and had short and long diameters of 1.1 +/- 0.2 mm and 1.3 +/- 0.2 mm, respectively. The residual isopropanol and caprylic triglyceride were <0.05% (w/w) and <1% (w/w) respectively. The level of bacterial endotoxins in the extracts was below 0.025 EU/ml, and no bacterial or fungal growth was found during sterility testing. The GSMs produced using this method were considered to meet the basic requirements of embolic agents.

Biodiesel fuel from Jatropha oil via non-catalytic supercritical methanol transesterification

Transesterification of Jatropha oil using supercritical methanol and in absence of a catalyst has been studied under different conditions of temperature (from 512 to 613 K), pressure (from 5.7 to 8.6 MPa) and molar ratio of alcohol to oil (from 10 to 43 mol alcohol per mol oil). The reaction products were analyzed for their content of residual triglycerides, glycerol, monoglycerides, diglycerides, esters and free acids by high performance liquid chromatography (HPLC), thin layer chromatography (TLC) and titration against KOH. The results have revealed that 100% yield of esters can be obtained using super critical methanol within four min only, at a temperature of 593 K and under a pressure of 8.4 MPa pressure. The molar ratio of methanol to oil was 43:1.

Acceleration of lipid degradation by sericoside of Terminalia sericea roots in Fully differentiated 3T3‐L1 cells

Sericoside is a traditional herbal saponin from Terminalia sericea (Family Combretaceae). The influence of sericoside on lipolysis was studied in fully differentiated 3T3-L1 cells, and glycerol release into the cytosol and residual triglyceride were measured. The addition of sericoside stimulated glycerol release into the cytosol from deposited triglyceride in a dose- and time-dependent manner. These data suggested that sericoside has a strong lipolytic activity.

Adipocyte Lipases and Defect of Lipolysis in Human Obesity

The mobilization of fat stored in adipose tissue is mediated by hormone-sensitive lipase (HSL) and the recently characterized adipose triglyceride lipase (ATGL), yet their relative importance in lipolysis is unknown. We show that a novel potent inhibitor of HSL does not inhibit other lipases. The compound counteracted catecholamine-stimulated lipolysis in mouse adipocytes and had no effect on residual triglyceride hydrolysis and lipolysis in HSL-null mice. In human adipocytes, catecholamine- and natriuretic peptide-induced lipolysis were completely blunted by the HSL inhibitor. When fat cells were not stimulated, glycerol but not fatty acid release was inhibited. HSL and ATGL mRNA levels increased concomitantly during adipocyte differentiation. Abundance of the two transcripts in human adipose tissue was highly correlated in habitual dietary conditions and during a hypocaloric diet, suggesting common regulatory mechanisms for the two genes. Comparison of obese and nonobese subjects showed that obesity was associated with a decrease in catecholamine-induced lipolysis and HSL expression in mature fat cells and in differentiated preadipocytes. In conclusion, HSL is the major lipase for catecholamine- and natriuretic peptide-stimulated lipolysis, whereas ATGL mediates the hydrolysis of triglycerides during basal lipolysis. Decreased catecholamine-induced lipolysis and low HSL expression constitute a possibly primary defect in obesity.

Effects of green tea catechin‐induced lipolysis on cytosol glycerol content in differentiated 3T3‐L1 cells

The influence of catechins in green tea on lipolysis in fully differentiated 3T3-L1 cells was studied and glycerol release into the buffer, cytosol and residual triglyceride were measured. The addition of (-)-epigallocatechin-3-gallate (EGCG) stimulated glycerol release into the cytosol significantly after incubation for 4 h, but had no effect on that into the buffer. However, (+)-catechins did not produce a significant increase in lipolysis. These data suggested that EGCG has strong lipolytic activity.

Efficient lipase catalysed production of a lubricant and surfactant formulation using a continuous solvent-free process

The transesterification of sunflower oil with a high oleic acid residue content (typically 83.5%) with butanol-1 by immobilised Lipozyme ® was carried out in a solvent free system and in a continuous way. During the first 6 h of reactor operation, a transition phase was observed, in which the main products were butyl ester and glycerol. This latter being insoluble in the reaction mixture, it is adsorbed onto the enzyme support thus leading to a decrease in enzyme performance. Step by step, less and less glycerol is produced and finally when glycerol is no longer produced a steady state is attained. The product composition is a mixture of butyl ester (65 molar%), monoglyceride (26 molar%), diglyceride (6 molar%) and residual triglyceride (3 molar%). This mixture has interesting lubricant and surfactant properties. The reactor was maintained without any loss in activity for a period of 3 months. This result is very different to that obtained using an organic solvent ( n-hexane) which leads to a total loss of enzyme activity within a few hours.

Effect of moisture on enzymatic reaction in supercritical carbon dioxide

The continuous acidolysis of triolein and stearic acid was carried out by an immobilized lipase to elucidate the characteristics of supercritical carbon dioxide (SC-CO2) as a reaction medium. At first, an effect of temperature and pressure on the water adsorption to the immobilized lipase in the SC-CO2 was examined. Then, the continuous interesterification of triolein and stearic acid by the moist immobilized lipase was examined. The amount of water adsorption to the immobilized lipase in the supercritical carbon dioxide measured under the condition of a different temperature and pressure has been expressed by a correlation equation of Freundlich type by using relative water standardized with the solubility of water in each condition. Optimum operating conditions of the interesterification by immobilized lipase in the SC-CO2 was 323 K, 16.9 MPa and adsorbed-water concentration of 2 wt%. The production rate obtained by enzymatic acidolysis in the SC-CO2 was found to be about 0.03 mmol/h×g-immobilized enzyme, leaving 74% residual triglyceride at the optimum operating conditions.

A Lecithin Cholesterol Acyltransferase-like Gene Mediates Diacylglycerol Esterification in Yeast

The terminal step in triglyceride biosynthesis is the esterification of diacylglycerol. To study this reaction in the model eukaryote, Saccharomyces cerevisiae, we investigated five candidate genes with sequence conservation to mammalian acyltransferases. Four of these genes are similar to the recently identified acyl-CoA diacylglycerol acyltransferase and, when deleted, resulted in little or no decrease in triglyceride synthesis as measured by incorporation of radiolabeled oleate or glycerol. By contrast, deletion of LRO1, a homolog of human lecithin cholesterol acyltransferase, resulted in a dramatic reduction in triglyceride synthesis, whereas overexpression of LRO1 yielded a significant increase in triglyceride production. In vitro microsomal assays determined that Lro1 mediated the esterification of diacylglycerol using phosphatidylcholine as the acyl donor. The residual triglyceride biosynthesis that persists in the LRO1 deletion strain is mainly acyl-CoA-dependent and mediated by a gene that is structurally distinct from the previously identified mammalian diacylglycerol acyltransferase. These mechanisms may also exist in mammalian cells.