The efforts have been made to review phyllosilicate derived (clay-based) heterogeneous catalysts for biodiesel production via lignocellulose derived feedstocks. These catalysts have many practical and potential applications in green catalysis. Phyllosilicate derived heterogeneous catalysts (modified via any of these approaches like acid activated clays, ion exchanged clays and layered double hydroxides) exhibits excellent catalytic activity for producing cost effective and high yield biodiesel. The combination of different protocols (intercalated catalysts, ion exchanged catalysts, acidic activated clay catalysts, clay-supported catalysts, composites and hybrids, pillared interlayer clay catalysts, and hierarchically structured catalysts) was implemented so as to achieve the synergetic effects (acidic-basic) in resultant material (catalyst) for efficient conversion of lignocellulose derived feedstock (non-edible oils) to biodiesel. Utilisation of these Phyllosilicate derived catalysts will pave path for future researchers to investigate the cost-effective, accessible and improved approaches in synthesising novel catalysts that could be used for converting lignocellulosic biomass to eco-friendly biodiesel.
- MeSH
- biomasa MeSH
- biopaliva * MeSH
- esterifikace MeSH
- katalýza MeSH
- lignin MeSH
- oleje rostlin * MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The successfulness of a lipase-catalyzed industrial process depends on a proper lipase selection. In this work, an alternative screening platform for industrially important biotransformations catalyzed by microbial lipases was proposed. Thus, the reactivity of sixty lipase activities from spore-forming microorganisms towards hydrolytic and transesterification reactions by using p-nitrophenyl palmitate as a chromogenic acyl donor substrate was explored. Only three biocatalysts were capable of catalyzing all reactions tested. Fourteen biocatalysts did not show hydrolytic activity at all; however, they displayed transesterification activities using ethanol, starch, low-methoxyl (LM) pectin, high-methoxyl (HM) pectin, or vitamin C as acyl acceptors. Using heat-treated biocatalysts, hydrolytic activities were not highly correlated with the corresponding transesterification activities using ethanol (r = -0.058, p = 0.660), starch (r = 0.431, p = 0.001), LM pectin (r = -0.010, p = 0.938), HM pectin (r = 0.167, p = 0.202), and vitamin C (r = -0.048, p = 0.716) as acyl acceptor. In addition, to the best of our knowledge, several transesterification activities produced from microorganisms of the genus Bacillus, Brevibacillus, Lysinibacillus, Geobacillus, or Sporosarcina were reported for first time. Finally, the global lipase market was presented and segmented by date, application, geography and player highlighting the commercial contribution of microbial lipases.
- MeSH
- biotransformace MeSH
- esterifikace MeSH
- hydrolýza MeSH
- katalýza MeSH
- lipasa * metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
The potential of new trimetallic (Ce, Cu, La) loaded montmorillonite clay catalyst for synthesizing biodiesel using novel non-edible Celastrus paniculatus Willd seed oil via two-step transesterification reaction has been reported along with catalyst characterization. Transesterification reaction was optimized and maximum biodiesel yield of 89.42% achieved under optimal operating reaction states like; 1:12 oil to methanol ratio, 3.5% of catalyst amount, 120 °C of reaction temperature for 3 h. The predicted and experimental biodiesel yields under these reaction conditions were 89.42 and 89.40%, which showing less than 0.05% variation. Additionally, optimum biodiesel yield can be predicted by drawing 3D surface plots and 2D contour plots using MINITAB 17 software. For the characterization of the obtained biodiesel, analysis including the GC/MS, FT-IR, 1H NMR and 13C NMR were applied. The fuel properties of obtained biodiesel agrees well with the different European Union (EU-14214), China (GB/T 20828), and American (ASTM-951, 6751) standards.
- MeSH
- bentonit * MeSH
- biopaliva * analýza MeSH
- esterifikace MeSH
- katalýza MeSH
- oleje rostlin analýza MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Čína MeSH
Tall fescue (Festuca arundinacea Schreb) shows remarkable tolerance to lead (Pb), but the mechanisms involved in metal tolerance are not yet well understood. Here, tall fescue were firstly cultivated hydroponically with Pb2+ (0, 50, 200 and 1000 mg/L) for 14 days. The results showed that remodeling of root architecture plays important roles in tolerance of tall fescue to Pb2+ stress. Increased cell wall (CW) components contribute to restrict high amount of Pb2+ in roots. Additionally, the uronic acid contents of pectin, hemicellulose 1 (HC1) and hemicellulose 2 (HC2) increased under Pb2+ stress. We further observed that tall fescue cultivated with H2O2 showed similar remodeling of root architecture as Pb2+ treatment. Furthermore, pectin, HC1 and HC2 fractions were sequentially extracted from 0 and 10 mM H2O2 treated roots, and Pb2+ adsorption capacity and contents of carboxyl groups of pectin and HC2 fractions were steadily increased under H2O2 treatment in vitro. Our results suggest that degrees of esterification of pectin and HC2 are regulated by H2O2. High amount of low-esterified pectin and HC2 offer more carboxyl groups, provide more Pb2+ binding sites, and restrict more Pb2+ in the CW, which may enhance tolerance of tall fescue to Pb2+ stress.
- MeSH
- buněčná stěna účinky léků metabolismus MeSH
- esterifikace MeSH
- Festuca účinky léků metabolismus MeSH
- kořeny rostlin účinky léků metabolismus MeSH
- látky znečišťující půdu metabolismus toxicita MeSH
- olovo metabolismus toxicita MeSH
- oxidační stres účinky léků MeSH
- polysacharidy chemie metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Chitosan and β-glucan are substances that are very widely used in the pharmaceutical and food industries, medicine and other areas. These polysaccharides have immense significance in human metabolism. They are able to affect the levels of cholesterol and lipids. Chemical modification of these polysaccharides allows the support of these attributes. A main goal is to prepare a group of amide derivatives of carboxymethyl chitosan and carboxymethyl β-glucan to obtain a new group of polysaccharide derivatives and increase the benefits and attributes of these polysaccharides. The aim of carboxymethylation and subsequent two-step amidation is to achieve a high degree of substitution in the prepared derivatives. The amidation consisted methyl esterification followed by amino-de-alkoxylation with amidation reagents (n-alkylamines, hydrazine and hydroxylamine). The purity and substitution degree of the prepared derivatives were monitored by vibration spectroscopic methods (FTIR and FT Raman) and organic elemental analysis. The main, which was due to the presence of a secondary component (chitin) of polysaccharides, was the calculation of the substitution degree, which was based on the organic elemental analysis in combination with FTIR spectroscopy. These analytic methods confirmed the preparation of the substituted N-alkylamides, hydrazide and hydroxamic acid of carboxymethyl chitosan and carboxymethyl β-glucan.
- MeSH
- beta-glukany chemie MeSH
- chitin chemie MeSH
- chitosan analogy a deriváty chemie MeSH
- esterifikace MeSH
- hydraziny chemie MeSH
- hydrofobní a hydrofilní interakce MeSH
- lidé MeSH
- polysacharidy chemie MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
The paper describes transesterification of oil by methanol with use of cosolvents such as ethyl acetate, tetrahydrofuran, hexane, acetone and diethyl ether at catalyst homogeneous (potassium hydroxide) and heterogeneous (mixed oxides). The cosolvents dissolve oil and methanol to form a single (homogeneous) phase, which increases the reaction rate. Therefore, the biodiesel production will be environmentally friendly because less energy is consumed, which increases sustainability. The whole binodal curve of ternary plots of oil, methanol and cosolvent was determined to find the molar ratio, in which the reaction mixture forms a single phase. The ethyl acetate and tetrahydrofuran have relatively small heterogeneous region, because of the similarity of their electric dipole moment with methanol. After transesterification, the detailed analysis of ester and also glycerol phase was carried out. For homogeneous catalyst, the highest esters content in the ester phase was achieved with tetrahydrofuran. For heterogeneous catalyst, the ester content was lower with cosolvent than without cosolvent, probably due to dilution of reaction components by cosolvent or bonding of cosolvent to the active sites of the catalyst.
- MeSH
- biopaliva * MeSH
- esterifikace MeSH
- estery * MeSH
- katalýza MeSH
- methanol MeSH
- oleje rostlin MeSH
- Publikační typ
- časopisecké články MeSH
A new method for the preparation of anhydrous ethyl ester of lactic acid was studied. The selected method is based on catalytic transesterification of lactic acid oligomers, which were prepared for this purpose by autocatalytic oligomerization of lactic acid. In this work, a kinetic model for the case of catalytic alcoholysis of oligoesters was derived assuming a first-order reaction and equimolar content of reactants in the reaction mixture. The model makes it possible to obtain the values of the reaction rate and equilibrium constants and the equilibrium alcohol concentration by regression analysis at one time. The model was verified by measuring the rate of consumption of ethanol over the time at various reaction temperatures with anhydrous FeCl₃ as the catalyst. The reaction was studied at overpressure under autogenous conditions in the temperature range of 100⁻180 °C. For the catalyst concentration of 1 mol %, the activation energy value was 64.35 kJ·mol-1. The dependence of equilibrium composition and rate constant on the temperature was obtained. The derived model is generally applicable to all first-order equilibrium reactions. The presumption is that the forward and reverse reactions are of the same order and have the same stoichiometry and equivalent amounts of reactants at the beginning of the reaction.
4-Carboxy-α-[3-(hydroxyamino)-3-oxopropyl]-benzenepropanoic acid 1 is a potent hydroxamate-based inhibitor of glutamate carboxypeptidase II. In an attempt to improve its poor oral pharmacokinetics, we synthesized a series of prodrugs by masking its hydrophilic hydroxamate group. Prodrugs were evaluated for oral availability in mice and showed varying degree of plasma exposure to 1. Of these, para-acetoxybenzyl-based, 4-(5-(((4-acetoxybenzyl)oxy)amino)-2-carboxy-5-oxopentyl)benzoic acid, 12, provided 5-fold higher plasma levels of 1 compared to oral administration of 1 itself. Subsequently, para-acetoxybenzyl-based prodrugs with additional ester promoiety(ies) on carboxylate(s) were examined for their ability to deliver 1 to plasma. Isopropyloxycarbonyloxymethyl (POC) ester 30 was the only prodrug that achieved substantial plasma levels of 1. In vitro metabolite identification studies confirmed stability of the ethyl ester of benzoate while the POC group was rapidly hydrolyzed. At oral daily dose-equivalent of 3 mg/kg, 12 exhibited analgesic efficacy comparable to dose of 10 mg/kg of 1 in the rat chronic constrictive injury model of neuropathic pain.
- MeSH
- analgetika chemie farmakokinetika farmakologie terapeutické užití MeSH
- aplikace orální MeSH
- esterifikace MeSH
- glutamátkarboxypeptidasa II antagonisté a inhibitory metabolismus MeSH
- inhibitory enzymů chemie farmakokinetika farmakologie terapeutické užití MeSH
- krysa rodu rattus MeSH
- kyseliny hydroxamové chemie farmakokinetika farmakologie terapeutické užití MeSH
- lidé MeSH
- myši MeSH
- neuralgie farmakoterapie enzymologie MeSH
- objevování léků MeSH
- potkani Sprague-Dawley MeSH
- prekurzory léčiv chemie farmakokinetika farmakologie terapeutické užití MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
It is becoming increasingly apparent that mutual interactions between adipocytes and immune cells are key to the integrated control of adipose tissue inflammation and lipid metabolism in obesity, but little is known about the non-inflammatory functions of adipose tissue macrophages (ATMs) and how they might be impacted by neighboring adipocytes. In the current study we used metabolipidomic analysis to examine the adaptations to lipid overload of M1 or M2 polarized macrophages co-incubated with adipocytes and explored potential benefits of omega-3 polyunsaturated fatty acids (PUFA). Macrophages adjust their metabolism to process excess lipids and M2 macrophages in turn modulate lipolysis and fatty acids (FA) re-esterification of adipocytes. While M1 macrophages tend to store surplus FA as triacylglycerols and cholesteryl esters in lipid droplets, M2 macrophages channel FA toward re-esterification and β-oxidation. Dietary omega-3 PUFA enhance β-oxidation in both M1 and M2. Our data document that ATMs contribute to lipid trafficking in adipose tissue and that omega-3 PUFA could modulate FA metabolism of ATMs.
- MeSH
- esterifikace MeSH
- kultivované buňky MeSH
- lipolýza * MeSH
- makrofágy metabolismus MeSH
- mastné kyseliny metabolismus MeSH
- metabolismus lipidů MeSH
- myši inbrední C57BL MeSH
- omega-3 mastné kyseliny metabolismus MeSH
- tuková tkáň cytologie metabolismus MeSH
- tukové buňky metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
