Co-reporter:Guo Sun, Ying Li, Zizhe Cai, Yinglai Teng, Yong Wang, Martin J.T. Reaney
Applied Catalysis B: Environmental 2017 Volume 209(Volume 209) pp:
Publication Date(Web):15 July 2017
DOI:10.1016/j.apcatb.2017.02.078
•Comprehensive study on HT/K2CO3 catalyst for biolubricant base oil production.•Both catalyst preparation and transesterification conditions were optimized.•Metal ion leaching was significantly reduced by optimal HT/K2CO3 catalyst.•Reactivation methods were firstly investigated for the optimal catalyst recycling.•The catalyst performance, quality and function mechanism were elaborated.Hydrotalcite (HT) loaded with potassium carbonate (K2CO3) was originally applied as a promising heterogeneous solid base catalyst for the production of trimethylolpropane fatty acid triester (TFATE) as the biolubricant base oil through transesterification of fatty acid methyl esters (FAME) from waste cooking oils and trimethylolpropane (TMP), in which FAME to TMP ratio (3:1), catalyst dosage (2% w/w), pressure (300 Pa), temperature (160 °C) and time (2 h) were optimized in order to obtain the best TFATE yield (80.6%). Based on the above, K2CO3 dosage (30% w/w) and calcination temperature (500 °C) in the preparation of HT/K2CO3 catalyst were optimized to improve the TFATE yield to 93.9% along with 97.7% of conversion rate of FAME (CRF). The catalyst recycling was also investigated to determine the suitable reactivated method. Besides, HT/K2CO3 catalysts in various states were characterized for better comprehension of their functional mechanisms and appropriate potential applications.Download high-res image (143KB)Download full-size image
Co-reporter:Zhen Zhang, Xiang Ma, Huihua Huang, Yong Wang
LWT - Food Science and Technology 2017 Volume 86(Volume 86) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.lwt.2017.08.035
•Compatibility tests above 25 °C showed that SheaOL25 could serve as blending base oil for preparing specialty fats.•Blending SheaOL25 and palm stearin had positive impacts on the crystallization behavior of the system utilized.•Stability of O/W emulsion system with SheaOL25 as oil phase was significantly improved.•Findings will contribute to expand the application of shea olein in production of specialty fats.To expand low melting point “liquid” base oil categories of plastic fats, the soft fat named SheaOL25 as a byproduct of shea butter with a melting point of 25.5 °C was achieved via solvent fractionating of shea butter, and abounded in oleic acid and stearic acid/oleic acid/oleic acid (SOO) type triacylglycerols. The compatibility test with palm-based oil and coconut oil showed the desirable linear relationship of isothermal curve. At temperatures above 25 °C, SheaOL25 exhibits good compatibility and could serve as a blending base oil for preparing specialty fats. Compared with palm olein, blending SheaOL25 and palm stearin can significantly expedite crystallization rate and retard crystallization rate after interesterification, thereby stabilizing the β′ crystal form in the system. Further exploration of SheaOL25 as “liquid” oil in oil-in-water emulsion system revealed that SheaOL25 as the oil phase can significantly improve the system's stability compared with the control groups of soybean oil and palm olein towards maintaining the particle size and emulsion stability under high temperatures.
Co-reporter:Chaoying Qiu, Bin Wang, Yong Wang, Yinglai Teng
Food Hydrocolloids 2017 Volume 69(Volume 69) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.foodhyd.2017.02.020
•Gliadin and its conjugates were applied to form colloidal complexes with Resveratrol.•Nanocomplexes formation could protect Res from UV-light transformation.•Res stability was efficiently improved in nanocomplexes during in vitro digestion.•Dextran moieties on protein enhanced Res bioaccessibility due to steric hindrance.•Protein-Res complexes could significantly lower lipid oxidation in emulsion.Deamidated wheat gliadin (gliadin) and its conjugates were applied to form complexes with resveratrol (Res). Res is a kind of polyphenol known for its low bioavailability and solubility in aqueous solution. The morphology of the complexes and Res stability were compared. Colloidal complexes were incorporated into emulsion to evaluate antioxidant activity. Results indicated that both gliadin and glycosylated gliadin can form nanocomplexes with Res and had high retention efficiency. Colloidal complexes solution can efficiently protect Res from UV-light transformation and the content of trans-Res was significantly improved (p < 0.05). Higher Res bioaccessibility in the complexes after digestion indicated that colloidal complexes can efficiently increase Res stability during gastrointestinal digestion. Dextran moieties were more efficient to enhance Res bioaccessibility due to steric hindrance. In the emulsion system, the colloidal complexes can significantly lower lipid oxidation evaluated by lipid hydroperoxides and hexanal generation during storage. The emulsifying properties of protein promoted the accumulation of Res at the oil-water surface. Therefore, it can act as an antioxidant to inhibit lipid oxidation. These results proved that the gliadin based delivery system is efficient to incorporate bioactive compounds in food beverages and emulsions.Download high-res image (81KB)Download full-size image
Co-reporter:Shan Liang, Wenzhen Liao, Xiang Ma, Xiaofeng Li, Yong Wang
Food Chemistry 2017 Volume 230(Volume 230) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.foodchem.2017.03.029
•H2O2 oxidative method was applied to degrade flaxseed gum.•The degradation rate could reach 37.4% under optimized conditions.•Characterizations of FGOS were conducted via HPLC-SEC, GC, FTIR, NMR and FESEM in detail.•FGOS was found to exhibit potent OH, DPPH and ABTS scavenging activity.In this present study, a novel flaxseed gum oligosaccharide (FGOS) was prepared by H2O2 oxidative degradation method followed by physicochemical properties characterization and antiradical activity evaluation. Results indicated that the degradation rate of flaxseed gum is 37.81% under the optimum conditions (i.e., reaction temperature of 120 °C, H2O2 concentration of 0.2 M and reaction time of 2.0 h) and FGOS as a reddish brown semisolid was obtained. Physicochemical properties identification showed that FGOS has a molecular weight of 1047 Da and is a typical oligosaccharide which contains uronic acid. Characterizations showed FGOS is acid glycopyranose that consists of rhamnose, fucose, xylose, mannose, arabinose, glucose and galactose with mole percentages of 8.26%, 7.54%, 12.85%, 7.93%, 29.31%, 14.28% and 19.82% respectively. FGOS exhibited good free radical scavenging ability (OH 82.58%, DPPH 52.74% and ABTS 91.29% at most, respectively), suggesting its potent antiradical activity.
Co-reporter:Zhen Zhang, Huihua Huang, Xiang Ma, Guanghui Li, ... AiJun Li
Journal of Industrial and Engineering Chemistry 2017 Volume 53(Volume 53) pp:
Publication Date(Web):25 September 2017
DOI:10.1016/j.jiec.2017.05.001
A new and efficient technique is described for the production of diacylglycerols (DAGs) by the esterification of oleic acid with glycerol catalyzed by diatomite-loaded SO42−/TiO2. DAGs show some potential health benefits compared to triacylglycerols, and also can be used to produce the novel industrial plasticizer epoxy fatty acid methyl ester in material science. Diatomite-loaded SO42−/TiO2 catalyst was prepared and characterized, and the selected conditions for the synthesis of DAGs were determined to be: reaction time = 6.0 h, temperature = 210 °C, catalyst loading = 0.1% of the oleic acid weight, and mass ratio of oleic acid to glycerol = 2:1. Under these conditions, DAGs yield reached 59.6% with a purity of 69.6% after a one-stage molecular distillation. Diatomite-loaded SO42−/TiO2 as a solid catalyst could be recycled and reused with high catalytic efficiency. Under the same conditions, diatomite-loaded SO42−/TiO2 showed a better catalytic performance than the commercial solid acid SO42−/ZrO2-Al2O3. Based on this, a two-step reaction method for the production of DAGs was performed and provided a yield similar to the one-step method (58.3% vs. 59.6%), but with a shorter reaction time (4 h vs. 6 h). It is concluded that a two-step reaction method could be a better alternative to the one-step production of DAGs in the presence of diatomite-loaded SO42−/TiO2.Download high-res image (219KB)Download full-size image
Co-reporter:Zhen Zhang;Xiang Ma;Huihua Huang
Journal of the American Oil Chemists' Society 2017 Volume 94( Issue 9) pp:1175-1188
Publication Date(Web):31 July 2017
DOI:10.1007/s11746-017-3023-x
MDs [monoacylglycerols (MAGs) and diacylglycerols (DAGs) mixture] are widely-used emulsifiers in specialty fats industrial production. An enzymatic production of highly unsaturated MDs (HUSMDs) and its effects on the storage stability of a palm oil-based shortening system are reported. Oleic acid and corn oil were used to produce HUSMDs in a bubble column reactor (BCR) system in the presence of Novozyme 435. Under the optimized reaction conditions, the content of HUSMDs in the products was above 82 wt% with 46.67 wt% of MAGs and 35.56 wt% DAGs, respectively. Moreover, in the subsequent evaluation of MDs’ effects on the storage stabilities of a palm oil-based shortening system (IEPO), HUSMDs proved to be a potent emulsifier with decent aeration properties and a possible alternative to saturated MAGs and DAGs (SMDs) made from fully hydrogenated high erucic acid colza oil. Compared with SMDs, HUSMDs decreased the crystallization rate significantly. The microstructure of them shows improved stability of β′ crystals, and no obvious aggregation of crystals was recorded in IEPO with HUSMDs, which also demonstrated the most stable hardness.
Co-reporter:Wenzhen Liao, Wen Li, Tiantian Zhang, Micheal Kirberger, Jun Liu, Pei Wang, Wei Chen and Yong Wang
Biomaterials Science 2016 vol. 4(Issue 8) pp:1266-1266
Publication Date(Web):22 Jun 2016
DOI:10.1039/C6BM90031C
Correction for ‘Powering up the molecular therapy of RNA interference by novel nanoparticles’ by Wenzhen Liao et al., Biomater. Sci., 2016, DOI: 10.1039/c6bm00204h.
Co-reporter:Wenzhen Liao, Wen Li, Tiantian Zhang, Micheal Kirberger, Jun Liu, Pei Wang, Wei Chen and Yong Wang
Biomaterials Science 2016 vol. 4(Issue 7) pp:1051-1061
Publication Date(Web):25 May 2016
DOI:10.1039/C6BM00204H
RNA interference technology has been widely applied in biomedical therapy in recent years. A type of small RNA molecule – siRNA could regulate the expression of disease related genes by breaking down the integrity of mRNA with high specificity. However, the low efficiency of siRNA delivery to its target seriously hampered the RNAi therapy. Compared with viral-based delivery systems, non-viral-based nanoparticles are more suitable for disease treatment due to reduced cellular toxicity, higher loading capacity, and better biocompatibility. This review article highlights several nanoparticle-based siRNA delivery systems, including liposomes, cationic solid lipid nanoparticles, reconstituted high density lipoprotein, polymeric nanoparticles, cationic cell penetrating peptides, and inorganic nanoparticles. The molecular mechanism of gene silencing, clinical examples, and the limitations of current technology related to nanomaterial sciences, are also discussed.
Co-reporter:Wenzhen Liao, Luying Chen, Xiang Ma, Rui Jiao, Xiaofeng Li, Yong Wang
European Journal of Medicinal Chemistry 2016 Volume 114() pp:24-32
Publication Date(Web):23 May 2016
DOI:10.1016/j.ejmech.2016.02.045
•Kaempferol exhibited strong cellular antioxidant ability by scavenging the accumulation of ROS.•Pretreatment with kaempferol significantly attenuated the ROS-induced hemolysis.•Kaempferol preserved the activities of antioxidant enzymes to normal levels.•Kaempferol showed significant antiproliferative activity against several human cancer cells.•Kaempferol induced apoptosis of MCF-7 cells through the mitochondrial pathway.The protective effects of kaempferol against reactive oxygen species (ROS)-induced hemolysis and its antiproliferative activity on human cancer cells were evaluated in this study. Kaempferol exhibited strong cellular antioxidant ability (CAA) with a CAA value of 59.80 ± 0.379 μM of quercetin (QE)/100 μM (EC50 = 7.74 ± 0.049 μM). Pretreatment with kaempferol significantly attenuated the ROS-induced hemolysis of human erythrocyte (87.4% hemolysis suppressed at 100 μg/mL) and reduced the accumulation of toxic lipid peroxidation product malondialdehyde (MDA). The anti-hemolytic activity of kaempferol was mainly through scavenging excessive ROS and preserving the intrinsic antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx) activities in normal levels. Additionally, kaempferol showed significant antiproliferative activity on a panel of human cancer cell lines including human breast carcinoma (MCF-7) cells, human stomach carcinoma (SGC-7901) cells, human cervical carcinoma (Hela) cells and human lung carcinoma (A549) cells. Kaemperol induced apoptosis of MCF-7 cells accompanied with nuclear condensation and mitochondria dysfunction.
Co-reporter:Fenlong Wan;Yinglai Teng;Long Zou
Journal of the American Oil Chemists' Society 2016 Volume 93( Issue 12) pp:1605-1614
Publication Date(Web):2016 December
DOI:10.1007/s11746-016-2895-5
Liquid oils containing high-melting diacylglycerols (DAGs) are more likely to cause precipitation than triacylglycerol-based oils during long-term storage, which is not desired for consumer products. Therefore, we attempted to retard the crystallization of high-melting DAGs by adding emulsifiers, diglycerol esters of fatty acids (DGEs), which were synthesized by esterification of diglycerol and linoleic acid using Novozym 435. The reaction product was isolated by silica gel column chromatography to obtain pure mono-, di-, and triesters of diglycerol, and the composition was analyzed by HPLC and ESI-MS. Further structural analysis of the purified products was performed by 1H- and 13C-NMR. The retardation effect of DGEs with a different esterification degree on the crystallization of DAGs was investigated using solid fat content, differential scanning calorimetry, polarized light microscopy, and X-ray diffraction. The results reveal that addition of 0.5 % (w/w) DGEs could effectively retard the crystallization of high-melting DAGs by inhibiting the nucleation process and delaying the crystal growth, but their addition did not alter the crystal forms of DAGs. Moreover, the retardation effect was enhanced as the esterification degree of DGE decreased.
Co-reporter:Manman Liu;Junning Fu;Yinglai Teng
Journal of the American Oil Chemists' Society 2016 Volume 93( Issue 5) pp:637-648
Publication Date(Web):2016 May
DOI:10.1007/s11746-016-2804-y
In this study, diacylglycerols (DAG) were synthesized rapidly (~30 min) in a solvent-free system via esterification of glycerol with fatty acids (FA, the mixture of 60 wt% palm oil deodorizer distillate and 40 wt% oleic acid) catalyzed by Lipozyme 435 (Novozymes A/S, Copenhagen, Denmark) using a bubble column reactor. The content of DAG, monoacylglycerols (MAG), triacylglycerols (TAG) and free fatty acids (FFA) in the crude product were 57.94 ± 1.60 wt%, 24.68 ± 2.08 wt%, 2.67 ± 1.72 wt% and 14.69 ± 1.22 wt%, respectively under the selected conditions, which were enzyme load of 5.0 wt%, glycerol/FA mole ratio of 7.5, initial water content of 2.5 wt%, reaction temperature of 60 °C, reaction time of 30 min and N2 gas flow of 10.6 cm min−1. The final product containing 91.30 ± 1.10 wt% of DAG was obtained by one-step molecular distillation at 200 °C. The reusability of Lipozyme 435 was investigated by evaluating the esterification degree (ED) and the DAG content in the crude products in 30 successive runs. The enzyme retained 95.10 % of its original activity during 30 successive runs according to comparison of the ED. The new process showed a very high efficiency in production of DAG with a high purity. The ratio of positional isomers 1,3-DAG to 1,2 -DAG was 2:1 in the final product. The certain plasticity (melting point of 44 °C) and content of unsaturated fatty acids made the product a valuable food ingredient.
Co-reporter:Zi-Zhe Cai, Yong Wang, Ying-Lai Teng, Ka-Man Chong, Jia-Wei Wang, Jie-Wen Zhang, De-Po Yang
Fuel Processing Technology 2015 Volume 137() pp:186-193
Publication Date(Web):September 2015
DOI:10.1016/j.fuproc.2015.04.017
•A practical two-step process was developed to convert WCO with a high FFA content into FAME.•Crude glycerol from the second step was recycled as reactant for the first step.•An alkali catalyst was used in the esterification to lower FFA content of WCO.•Excess glycerol separation is not needed in the esterification step.•Significant energy and time saving have been achieved as compared to the traditional methanol esterification with methanol.A novel biodiesel production process using waste cooking oil (WCO) as feedstock was developed in this work. Free fatty acids (FFAs) from WCO were esterified by crude glycerol catalyzed by NaOH, which lowered the content of free fatty acids of WCO. The conversion of FFA in the WCO (acid value: 124.9 mg KOH/g) to acylglycerols is 99.6% under the optimal conditions (1.4:1 molar ratio of glycerol to FFA, 4 h, 210 °C, catalyst loading 0.5 wt.% based on WCO weight). After the transesterification of esterified WCO with methanol catalyzed by NaOH, the yield of the final product is 93.1 wt.% with 98.6 wt.% of fatty acid methyl ester (FAME). The crude glycerol and the catalyst from transesterification were recycled as reactant for esterification during the biodiesel production. Soap formed from the subsequent processes maintained a high catalyzing activity for FFA esterification after being recycled for 13 times. This new glycerol esterification process using alkali (soap) catalyst provides a promising solution to convert feedstock with high FFA levels to biodiesel. This biodiesel production process has distinct advantages compared with traditional two-step methods, including lower cost of catalyst for both esterification and transesterification processes, less energy consumption for methanol recovery, recycling of the glycerol byproduct and catalyst (soap), and no requirement of anti-corrosive equipment.
Co-reporter:Zhen Zhang, Yong Wang, Xiang Ma, Erpei Wang, Manman Liu, Rian Yan
Food Chemistry 2015 Volume 173() pp:70-79
Publication Date(Web):15 April 2015
DOI:10.1016/j.foodchem.2014.09.155
•.Partially hydrogenated corn oils were used to produce monoacylglycerols through glycerolysis catalysed by a solid base catalyst.•Monoacylglycerols with purities over 90 wt.% was obtained by a two-step molecular distillation.•Purified monoacylglycerols with different fatty acid composition were characterised using XRD, FT-IR and DSC.•The oxidation stability of the monoacylglycerols has been significantly improved by partial hydrogenation.This study reported the characterisation of some types of monoacylglycerols (MAGs) obtained by the glycerolysis of different partially hydrogenated corn oils (PHCOs) catalysed by Al2O3 loaded with K2CO3 (K2CO3/Al2O3) under the previous selected conditions. A two-stage molecular distillation method of purifying the MAGs was introduced, and the obtained MAG products were more than 90.0 wt.% pure. The fatty acid composition of corn oil significantly changed after hydrogenation sequentially catalysed by Pricat™ Ni catalysts (9908 Ni/kieselguhr and 9920 Ni/Al2O3). The PHCO samples generated typical structures with β′-form crystals. Moreover, the melting regions of all hydrogenated samples and their MAGs shifted to higher temperatures. The oxidation stability of MAGs has been significantly increased using hydrogenation to change the fatty acid composition.
Co-reporter:Ziliang Song;Guoqiang Li;Wei Tan;Shengwen Yao
European Journal of Lipid Science and Technology 2015 Volume 117( Issue 7) pp:918-925
Publication Date(Web):
DOI:10.1002/ejlt.201400332
A new approach for determination of glycidyl fatty acid esters (GDEs) based on 1H nuclear magnetic resonance (1H NMR) spectroscopy was developed. The 1H NMR spectra of the GDE standards were prepared and characterized. The quantification formula was then deduced from the characteristic signals of two epoxy methylene (CH2) protons at chemical shifts 2.56 and 2.76 ppm. Tests on repeatability, reproducibility, and recovery were conducted and proved the reliability of the quantification method. This method was extended to GDEs mixed with oil matrices composed of different acylglycerols (GREs). The weighted average factor fw is introduced to calculate the fatty acid composition based on the stoichiometric proportion of the lipid component and its esterification degree. With the fatty acid composition determined, the molar percentage obtained from 1H NMR can be converted to the weight percentage. This method is an analytical model for the determination of GDEs, with advantages such as easy operation and high accuracy.
Practical applications: Heat treatment of edible oils in the refinery process can generate GDEs, a group of contaminants having potential risks to liberate a carcinogenic compound called glycidol during digestion of oil in the human body. It has become an important issue for the oil industry to develop an effective method for the determination of GDEs. The proposed 1H NMR spectroscopic method is able to characterize and quantify GDEs in an accurate, rapid, and noninvasive way. With these advantages, the analytical results also provide quantitative criteria for subsequent concentration and mitigation of GDEs in refined edible oils.
A novel 1H NMR spectroscopic method was developed to determine glycidyl fatty acid esters (GDEs), a processing contaminant in refined edible oil.
Co-reporter:Ziliang Song
European Journal of Lipid Science and Technology 2013 Volume 115( Issue 10) pp:1198-1200
Publication Date(Web):
DOI:10.1002/ejlt.201300166
Co-reporter:Yong Wang;Shun Ma;Lili Wang;Shuze Tang;William W. Riley;Martin J. T. Reaney
European Journal of Lipid Science and Technology 2012 Volume 114( Issue 3) pp:315-324
Publication Date(Web):
DOI:10.1002/ejlt.201100111
Abstract
The free fatty acids (FFAs) of waste cooking oil (WCO) are readily esterified with crude glycerol in the presence of the solid superacid SO/ZrO2–Al2O3. This reaction lowers the acidity of WCO before biodiesel production. The solid superacid SO/ZrO2–Al2O3 catalyzes both FFA esterification and TAG glycerolysis during the reaction. The conversion of FFA in the WCO with an acid value of 88.4 ± 0.5 mg KOH/g to acylglycerols was 98.4% under optimal conditions (mole ratio of glycerol to FFA = 1.4:1; reaction time = 4 h; reaction temperature = 200°C; catalyst loading = 0.3 wt%) obtained through an orthogonal experiment. The final FAME product with a FAME content of 96.9 ± 0.3 wt% yield was 94.8 wt%, after transesterification of the esterified WCO with methanol, catalyzed by potassium hydroxide. The FAME composition of the products produced by transesterification were identified and quantified by GC–MS. The results suggest that this new glycerol esterification process, using a solid superacid catalyst, affords a promising method to convert oils with high FFA levels, like WCO, to biodiesel. The process has the inherent advantage of easy separation steps for removing excess alcohol and significant savings in energy, when compared to acid catalyzed reactions with methanol to lower acidity.
Practical applications: In this work, WCO with a high acid value was esterified with crude glycerol catalyzed by solid super acid, whose formula was expressed as SO/ZrO2–Al2O3. There are distinct advantages to this new esterification process, which include easy separation of the excess crude glycerol by sedimentation or centrifugation, the use of the low cost reactant crude glycerol direct from the byproducts of transesterification, the potential to achieve a very low content of FFAs by post-refining to improve the yield of the final product, and time and energy saving are found as compared to the traditional methanol esterification process. This new technology provides a promising alternative method for processing feedstocks of high acid value, such as WCO, for the production of biodiesel.
Co-reporter:Ning Liu;Min Fu;Qiangzhong Zhao
Applied Biochemistry and Biotechnology 2012 Volume 168( Issue 5) pp:1108-1120
Publication Date(Web):2012 November
DOI:10.1007/s12010-012-9845-y
A simple, rapid, and economic method of enzyme immobilization was developed for phospholipase Lecitase® ultra (LU) via interfacial adsorption. The effect of nature of the polystyrene supports and the kinetic behavior and stability of immobilized lecitase® ultra (IM-LU) were evaluated. Six macroporous resins (AB-8, X-5, DA-201, NKA-9, D101, D4006) and two anion resins (D318 and D201) were studied as the supports. DA-201 resin was selected because of its best immobilization effect for LU. Immobilization conditions were investigated, including immobilization time, pH, and enzyme concentration. IM-LU with a lipase activity of 1,652.4 ± 8.6 U/g was obtained. The adsorption process was modeled by Langmuir and Freundlich equations, and the experimental data were better fit for the former one. The kinetic constant (Km) values were found to be 192.7 ± 2.2 mM for the free LU and 249.3 ± 5.4 mM for the IM-LU, respectively. The Vmax value of free LU (169.5 ± 4.3 mM/min) was higher than that of the IM-LU (53.8 ± 1.5 mM/min). Combined strategies of scanning electron micrograph, thermogravimetric analysis, and Fourier transform infrared (FTIR) spectroscopy were employed to characterize the IM-LU. FTIR spectroscopy showed that the secondary conformation of the enzyme had changed after immobilization, through which a decrease of α-helix content and an increase of β-sheet content were observed. The IM-LU possessed an improved thermal stability as well as metal ionic tolerance when compared with its free form. The reusability of IM-LU was also evaluated through catalyzing esterification reaction between oleic acid and glycerol. It exhibited approximately 70 % of relative esterification efficiency after six successive cycles. This immobilized enzyme on hydrophobic support may well be used for the synthesis of structural lipids in lipid area.
Co-reporter:Yong Wang, Shun Ma, Mouming Zhao, Lina Kuang, Jieyu Nie, William W. Riley
Fuel 2011 Volume 90(Issue 3) pp:1036-1040
Publication Date(Web):March 2011
DOI:10.1016/j.fuel.2010.11.013
The use of surfactants and detergent fractionation to improve the cold flow properties of biodiesel from waste cooking oil (BWCO) was investigated. The effect of five types of surfactants, including sugar esters (S270 and S1570), silicone oil (TSA 750S), polyglycerol ester (LOP-120DP) and diesel conditioner (DDA) on the reduction of the cold filter plugging point (CFPP) of the BWCO, was evaluated, with the greatest reduction to the CFPP of the BWCO (from −10 °C to −16 °C) being was achieved by the addition of 0.02 wt% of polyglycerol ester (LOP-120P). Detergent fractionation of the BWCO was performed by first mixing partially crystallized biodiesel with a chilled detergent (sodium dodecylsulfate) solution accompanied by an electrolyte (magnesium sulfate), and then separating the mixture by centrifugation to obtain the BWCO liquid. An orthogonal experimental design was utilized to investigate the effects of the various parameters on detergent fractionation. The optimal parameters, as obtained by range analysis, were as follows: detergent loading 0.3 wt%, electrolyte loading 1.0 wt%, and water loading 150 wt%. The CFFP of the liquid biodiesel from waste cooking oil (LBWCO) was −17 °C with a yield of 73.1% when the detergent fractionation was performed under these conditions. A limited number of biodiesel physical and chemical properties were analyzed before and after the addition of surfactants and detergent fractionation.
Co-reporter:Lili Wang;Changying Hu;Qian Cao
Journal of the American Oil Chemists' Society 2011 Volume 88( Issue 10) pp:
Publication Date(Web):2011 October
DOI:10.1007/s11746-011-1821-0
Production of diacylglycerol-enriched oil by esterification of free fatty acids (FFA) with glycerol (GLY) using phospholipase A1 (Lecitase Ultra) was investigated in this work. The variables including reaction time (2–10 h), water content (2–14 wt%, FFA and GLY mass), enzyme load (10–120 U/g, FFA and GLY mass), reaction temperature (30–70 °C) and mole ratio of GLY to FFA (0.5–2.5) were studied. The optimum conditions obtained were as follows: reaction temperature 40 °C, water content 8 wt%, reaction time 6 h, molar ratio of GLY to FFA 2.0, and an enzyme load of 80 U/g. Under these conditions, the esterification efficiency (EE) of free fatty acids was 74.8%. The compositions of the FFA and acylglycerols of the upper oil layer (crude diacylglycerol) of the reaction mixture were determined using a high temperature gas chromatograph (GC). The crude diacylglycerol from the selected conditions was molecularly distilled at 170 °C evaporator temperatures to produce a diacylglycerol-enrich oil (DEO) with a purity of 83.1% and a yield of 42.7%.
Co-reporter:Yong Wang, Jieyu Nie, Mouming Zhao, Shun Ma, Lina Kuang, Xue Han and Shuze Tang
Energy & Fuels 2010 Volume 24(Issue 3) pp:2104-2108
Publication Date(Web):February 9, 2010
DOI:10.1021/ef901347b
In this work, a two-step catalyzed process was developed to produce biodiesel from waste cooking oil (WCO). First, free fatty acid (FFA) of the WCO with an acid value of 66.40 ± 1.08 mg KOH/g was esterified with methanol catalyzed by polyferric sulfate (PFS). Second, the esterified WCO was transesterified with methanol catalyzed by potassium hydroxide to produce crude biodiesel. The crude biodiesel was purified by molecular distillation to produce purified biodiesel (fatty acid methyl ester, FAME). The highest yield of FAME by molecular distillation from the crude biodiesel was 98.32% ± 0.17% at an evaporator temperature of 120 °C. PFS was removed efficiently from the esterified WCO by washing water after the recovery of methanol. The results revealed that this two-step process using a polyferric sulfate catalyst and molecular distillation is probably a promising method for the conversion of WCO.
Co-reporter:Yong Wang, Xingguo Wang, Yuanfa Liu, Shiyi Ou, Yanlai Tan, Shuze Tang
Fuel Processing Technology 2009 Volume 90(Issue 3) pp:422-427
Publication Date(Web):March 2009
DOI:10.1016/j.fuproc.2008.11.004
A ceramic membrane separation process for biodiesel refining was developed to reduce the considerable usage of water needed in the conventional water washing process. Crude biodiesel produced by refined palm oil was micro-filtered by ceramic membranes of the pore size of 0.6, 0.2 and 0.1 μm to remove the residual soap and free glycerol, at the transmembrane pressure of 0.15 MPa and temperature of 60 °C. The flux through membrane maintained at 300 L m− 2 h− 1 when the volumetric concentrated ratio reached 4. The content of potassium, sodium, calcium and magnesium in the whole permeate was 1.40, 1.78, 0.81 and 0.20 mg/kg respectively, as determined by inductively coupled plasma-atomic emission spectroscopy. These values are lower than the EN 14538 specifications. The residual free glycerol in the permeate was estimated by water extraction, its value was 0.0108 wt.%. This ceramic membrane technology was a potential environmental process for the refining of biodiesel.
Co-reporter:Wenzhen Liao, Wen Li, Tiantian Zhang, Micheal Kirberger, Jun Liu, Pei Wang, Wei Chen and Yong Wang
Biomaterials Science (2013-Present) 2016 - vol. 4(Issue 7) pp:
Publication Date(Web):
DOI:10.1039/C6BM00204H
Co-reporter:Wenzhen Liao, Wen Li, Tiantian Zhang, Micheal Kirberger, Jun Liu, Pei Wang, Wei Chen and Yong Wang
Biomaterials Science (2013-Present) 2016 - vol. 4(Issue 8) pp:NaN1266-1266
Publication Date(Web):2016/06/22
DOI:10.1039/C6BM90031C
Correction for ‘Powering up the molecular therapy of RNA interference by novel nanoparticles’ by Wenzhen Liao et al., Biomater. Sci., 2016, DOI: 10.1039/c6bm00204h.
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