Transesterification Activity Research Articles

Free and Substrate-Immobilised Lipases from Fusarium verticillioides P24 as a Biocatalyst for Hydrolysis and Transesterification Reactions.

Fungal enzymes are widely used in technological processes and have some interesting features to be applied in a variety of biosynthetic courses. Here, free and substrate-immobilised lipases from Fusarium verticillioides P24 were obtained by solid-state fermentation using wheat bran as substrate and fungal carrier. Based on their hydrolytic and transesterification activities, the lipases were characterised as pH-dependent in both reactions, with higher substrate conversion in an alkaline environment. Thermally, the lipases performed well from 30 to 45 °C, being more stable in mild conditions. Organic solvents significantly influenced the lipase selectivity using different vegetable oils as fatty acid source. Omega(ω)-3 production in n-hexane achieved 45% using canola oil, against ≈ 18% in cyclohexane. However, ω-6 production was preferably produced for both solvents using linseed oil with significant alterations in the yield (≈ 79% and 49% for n-hexane and cyclohexane, respectively). Moreover, the greatest enzyme selectivity for ω-6 led us to suppose a lipase preference for the Sn1 position of the triacylglycerol. Lastly, a transesterification reaction was performed, achieving 90% of ester conversion in 72 h. This study reports the characterisation and use of free and substrate-immobilised lipases from Fusarium verticillioides P24 as an economic and efficient method for the first time.

“Water-like” ammonium-based ionic liquids for lipase activation and enzymatic polymerization

Novel dual-functionalized ammonium-based hydrophobic ionic liquids (ILs) have been synthesized by mimicking the water structure to carry both ether group (hydrogen-bond acceptor) and tert-alcohol group (hydrogen-bond donor). These ammonium-type ionic solvents exhibit the advantage of lower viscosities (as low as 129 mPa s at 30 °C) than the imidazolium analogue (∼300 mPa s at 30 °C); more importantly, these “water-like” media are highly compatible with immobilized Candida antarctica lipase B (Novozym 435) in terms of producing high transesterification activities (1.5-fold higher than that in tert-butanol, and slightly higher than that in diisopropyl ether) and higher thermal stability than that in tert-butanol. To demonstrate the utilization of this new solvent system, enzymatic ring-opening polymerization (ROP) of ε-caprolactone using these “water-like” ILs as co-solvents was carried out to synthesize polyesters, achieving high molecular mass Mw (up to 18,000 Da) and high yields (up to 74 %).

K2O Doped Dolomite as Heterogeneous Catalyst for Fatty Acid Methyl Ester Production from Palm Oil

Biodiesel obtained from palm oil over an environmentally friendly catalyst is highlydesirable. For that matter, dolomite, a natural material was used as a catalyst in this work, and this included potassium oxide (K2O)-doped dolomite, 5 wt% K/D, 10 wt% K/D, 15 wt% K/D, and 20 wt% K/D. X-ray diffraction analysis of dolomite revealed the CaO and MgO phases with high crystallinity, in which intensity reduced after doped with varying concentrations of K2O. When the catalysts were evaluated, the K2O-doped dolomite exhibited a better catalytic activity for palm oil transesterification. In the presence of K2O, the methyl ester reached 98.7%, with the highest being displayed by 15 wt% K/D as compared to 87% over dolomite at reaction temperature of 60 °C, 12:1 methanol to palm oil ratio, 1 wt% catalyst amount and 1 h reaction time. SEM revealed that as more K2O was doped on dolomite, the particles became more agglomerated, with a reduced BET surface area of 1.3 m2/g in 20 wt% K/D as opposed to homogeneously small-sized MgO and CaO particles in dolomite with a high BET surface area of 19.0 m2/g. However, the high activity of the doped catalyst was dictated by the high amount of basic site, as evidenced in TPD-CO2 which showed an increase in the capacity of the basic site with an increased amount of K2O. The catalyst was also reusable up to six times with a negligible decrease in activity due to K+ leaching.

Biochemical Characterization of a Lipolytic Enzyme From Aspergillus oryzae That Hydrolyzes Triacylglycerol and Sterol Esters.

A novel lipolytic enzyme-encoding gene, lipO745, from Aspergillus oryzae RIB40 was cloned and expressed in Pichia pastoris. Purified recombinant LipO745 (rLipO745) had a molecular mass of approximately 60 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. rLipO745 exhibited maximum activity at 40 °C and pH 7.0 and was stable at temperatures ≤ 40 °C. The substrate specificity of purified rLipO745 was analyzed using α-naphthyl esters as artificial substrates and various triacylglycerol and sterol esters as natural substrates. From among a panel of α-naphthyl esters (C2-C16), α-naphthyl butyrate (C4), with an activity of 269 ± 3.3 units/mg protein, was the optimal substrate for hydrolysis by the purified recombinant protein. The Km and kcat values of rLiO745 for the C4 substrate were 0.073 ± 0.0012 mM and 608 ± 108 s-1, respectively. The purified recombinant enzyme had considerable hydrolytic activity toward tributyrin, tripalmitin, and triolein, indicating lipase activity, and toward cholesteryl acetate, butyrate, palmitate, and oleate, indicating sterol esterase activity. Transesterification activities between tributyrin and cholesterol or between tributyrin and campesterol were also determined.

Facile synthesis of hydrothermal stable hierarchically macro-mesoporous hollow microspheres γ-Al2O3-graphene oxide composite: As a new efficient acid-base catalyst for transesterification reaction for biodiesel production

Alumina-hollow-microspheres- Graphene oxide (GO) composites with hierarchical macro- mesoporous structure and controllable GO loadings from 2 to 20 wt% had been synthesized using a self-limiting hydrogel method. The composite with 5 wt% GO loading exhibited the best catalytic activity in sunflower oil transesterification, giving an oil conversion of 85.2% by using only 1.0 wt% catalyst to oil at 60 °C in traditional batch reactor. Furthermore, the same composite (GO(5 wt%)-alumina) exhibited higher oil conversion (97%) to methyl esters in autoclave reactor at 120 °C. The significant high activity of this composite toward oil conversion was attributed to that its macroporous structure facilitated the diffusion of products, and it has higher amounts of both acidic and basic oxygen functional groups than either the neat GO or alumina. In addition, GO(5 wt%)-alumina composite, also showed good water tolerance, as the oil conversion was varied from ca. 85.2 to 79.2% in 10 h when the water content in reaction mixture was increased from 0.0 to 3.0 wt%. Furthermore, the catalyst could be easily reused for at least six reaction cycles with loss in catalytic activity by factor of 3% and 14% for fresh and waste cooking oil respectively. The stability of this composite in liquid water at 200 °C for 12 h was also examined using variety of physicochemical techniques. It is shown that the presence of GO (5 wt%) inhibited the hydration of γ-alumina to form boehmite.

Analysis of Transesterification Activity at High Temperature of Zirconia-Based Solid Solution Catalysts

Analysis of Transesterification Activity at High Temperature of Zirconia-Based Solid Solution Catalysts

Calcined Aceh Bovine Bone (Bos indicus) Intercalated Lithium as An Inorganic Base Catalyst for Transesterification of Castor Oil

Realizing abundant availability of local bovine bone wastes in Aceh Province, Indonesia, this study is subjected to take competitive advantages from the local bovine bone waste for preparing an inorganic catalyst preparation. In detail, calcined Aceh bovine bones were successfully intercalated lithium through an impregnation method resulting in the inorganic base catalyst, which showed promising activity in the transesterification of castor oil. Prior to the experiment, the Aceh bovine bone waste was calcined at 900 oC in the air atmosphere for 4 hours, led to forming crystalline phases of hydroxyapatite [Ca5(PO4)3(OH)] and calcium oxide [CaO]. Also, the chemical modification of calcined bovine bone with lithium precursor has enhanced the physicochemical properties of the inorganic base catalyst. Finally, the intercalated Aceh bovine bone has shown a feasible activity in transesterification of castor oil into biodiesel, which yielding methyl ricinoleate as the main product.

Investigation of a Novel Catalyst KOH/K2CO3@γ-Al2O3 Toward Polycarbonate Diol Synthesis

Polycarbonate diols (PCDLs) are intermediates used in the synthesis of polyurethanes (PU), and therefore their efficient and green synthesis is a necessity. In this work, KOH/K2CO3@γ-Al2O3 catalysts were prepared and employed in the synthesis of PCDLs. A 4 wt% KOH/40 wt% K2CO3@γ-Al2O3 catalyst and a DMC: 1,4-BDO molar ratio of 1.25:1 exhibited the best activity for the reaction and gave a PCDL yield of 95% with a molecular weight of 4527 g·mol−1. Moreover, the catalyst could be reused 4 times without a significant loss of the catalytic activity in transesterification. The effects of the catalyst composition and reaction conditions on the synthesis of PCDLs were investigated. The results indicate that the catalyst amount and the molar ratio of DMC: 1,4-BDO can influence the purity of PCDLs. The reaction equation Catalyst preparation The synthesis of PCDLs using DMC and 1,4-BDO

Catalytic conversion of spent frying oil into biodiesel over raw and 12-tungsto-phosphoric acid modified clay

In the present work, locally available clay has been utilized to develop cost effective catalyst for biodiesel production from low cost feedstock. The selected clay was modified with different concentrations (5 wt%, 10 wt%, 20 wt%, 30 wt% and 40 wt %) of 12-tungstophosphoric acid (TPA) to enhance the capability of the selected clay in biodiesel production from spent frying oil. The synthesized catalyst was characterized with different analytical techniques to evaluate its physiochemical properties. The result suggested that the catalyst containing 10 wt% 12-tungstophosphoric acid (TPA) loading exhibited good trans-esterification activity to produce maximum biodiesel yield of 96% under the best reaction conditions: oil/methanol molar ratio, 1:10; catalyst amount, 0.7 g; reaction time, 4.5 h and reaction temperature, 85 °C.Moreover, the catalytic reusability of the synthesized catalyst was investigated to study its economic viability. The results suggested that the synthesized catalyst could be reused up to 6 times for biodiesel production without any high temperature treatment. Thus, the selected clay has the potential to be used as a starting material to develop an efficient catalyst for biodiesel production from low cost feedstock.

Transesterification activity of modified biochars from spent malt rootlets using triacetin

In this study, transesterification of triacetin was studied using biochar as a greener and environmentally friendly solid catalyst. Biochar and modified biochars were produced from spent malt rootlets with pyrolysis at 850 °C in limited oxygen atmosphere, treated with acid, base, or pure water, characterized with various physicochemical techniques, like N2 adsorption for the determination of Specific Surface Area, thermogravimetric analysis, Infra-Red spectroscopy, Xray powder diffraction and Potentiometric Mass Titration for the determination of acid-base behavior and tested for their transesterification activity. The physicochemical characterization of the biochars showed that the treatment had significant effect on the specific surface area, TGA curves and point of zero charge of the biochars. Treatment with NaOH results to a significant increase in point of zero charge of the biochar, removal of lignin and enrichment of Na on the surface of biochar. Treatment with H2SO4 increases the specific surface area and the microporosity, lowers the point of zero charge and removes almost completely the mineral deposits from the surface. It was found that the two most active biochars were the untreated and the treated with NaOH biochar. The transesterification activity is correlated well with the basicity of the samples. The activity of the biochars is similar to the activity obtained in homogenous catalysis and it is stable for at least 3 cycles. The results are promising and biochars from spent malt rootlets can be used in transesterification reaction for biofuels production.

Synthesis of Hierarchical SAPO‐5 & SAPO‐34 Materials by Post‐Synthetic Alkali Treatment and Their Enhanced Catalytic Activity in Transesterification

SAPO‐5 and SAPO‐34 materials were modified using post‐synthetic alkali treatment, which results in the formation of hierarchical SAPO‐5 and SAPO‐34 materials. To test the generation of mesoporosity, the modified materials were thoroughly characterized using XRD, FE‐SEM, TGA, ICP‐OES, and N2 adsorption/desorption techniques. Alkali treated SAPO‐5 and SAPO‐34 materials were utilized for the model reaction triacetin transesterification, under optimized conditions by varying the catalyst amount and reaction time: 90 % triacetin conversion with 66 % methyl acetate yield was achieved using modified SAPO‐5 catalyst, whereas 68 % triacetin conversion with 37 % methyl acetate yield was achieved using modified SAPO‐34 catalyst. The alkali treated SAPO‐5 catalyst was stable up to the 4th cycle.

Synthesis of Biodiesel from Kesambi Oil using Indigenous Lipase

Kesambi (Schleichera oleosa L.) is one of ligneous tree that is abundantly found in Timor island, East Nusa Tenggara Province of Indonesia. Kesambi is known as an important component in local smoked meat home industry. Kesambi is also a promising natural source for the production of biodiesel. Application of three lipolytic fungi that is isolated from kesambi seeds and the use kesambi seeds flour as medium for indigenous lipase synthesis (Aspergillus niger M1407 lipase) by Solid-State Fermentation (SSF) showed good result for lipase and biodiesel industry development. This study aimed to characterize biodiesel synthesis using indigenous lipase from kesambi seeds. Experiments were carried out through five stages namely: oil extraction from kesambi seeds, purification of kesambi oil (degumming), extraction of A. niger M1407 lipase, trans-esterification and esterification activity of A. niger M1407 lipase assay and characterization of biodiesel. Biodiesel synthesis using A. niger M1407 lipase through esterification reaction produced biodiesel with an average acid number of 0.33 and 0.40 mg/g, water content 9.52 % and 10.47 % and density 0.7 g/mL. Biodiesel obtained from kesambi oil has lower acid numbers and densities but higher water content compared to Indonesian National Standard (SNI) value. Optimalization of the biodiesel kesambi oil synthesis could be done through adjusting ethanol and kesambi oil ratio and also by reducing water as a by-product of esterification reaction.

Transesterification activity by a zinc(II)-Schiff base complex with theoretical interpretation

The article demonstrates the synthesis, structural characterization and transesterification activity of a mononuclear zinc(II) complex, [Zn(HL)(H2O)]·(H2O) (1) containing a previously reported Schiff base ligand, H3L = N,N′-bis(salicylidene)-1,3-diamino-2-propanol]. X-ray structural analysis of 1 reveals that Zn(II)-Schiff base complex crystallizes in hexagonal crystal system with P61 space group and adopts a distorted tetrapyramidal geometry. Self-assembled molecular units of 1 exhibit a beautiful construction of 3D crystalline architecture through intermolecular hydrogen bond wire. Zinc(II) complex displays an enhancement of fluorescence intensity in comparison to HL in methanol medium. Catalytic behaviour of 1 towards disodium salt of 2,4-dinitrophenylphosphate (PNPP) in aqueous-methanol medium exhibits good transesterification activity with initial rate constant value of 1.73 × 10−4 min−1. Detailed DFT calculations are also employed to cope with the geometrical parameters of 1 as well as to explore the proposed catalytic mechanism of transesterification activity.

Serum protein electrophoresis pattern alterations on lipidoses patients

Brown grease is a common waste product responsible for many sewer overflows and illnesses, and it contains useful free fatty acids and other hydrocarbon-like molecules. This work demonstrates the potential to transform nearly 100% of the brown grease into biodiesel, synthesis gas and bio-oil for use as biofuel or for power generation. A solid acid catalyst was synthesized with excellent activity for esterification of the free fatty acids and relatively high activity for transesterification of triglycerides, which make up the oil phase of the brown grease. The catalyst is synthesized using a tri-block copolymer template that leads to mesopores with diameters narrowly centered at 11.1 nm. Residual solids, which make up roughly 10% of the brown grease, were found by elemental analysis to be a hydrogen rich feedstock, with H/Ceff ratio greater than wood or sugar. Preliminary gasification and pyrolysis experiments illustrate nearly 100% conversion of the residual solids. Fast pyrolysis in a drop tube furnace at 600 °C produced oil consisting predominantly of long chain hydrocarbons.

Synthesis of Biodiesel from Kesambi Oil using Indigenous Lipase

Kesambi (Schleichera oleosa L.) is one of ligneous tree that is abundantly found in Timor island, East Nusa Tenggara Province of Indonesia. Kesambi is known as an important component in local smoked meat home industry. Kesambi is also a promising natural source for the production of biodiesel. Application of three lipolytic fungi that is isolated from kesambi seeds and the use kesambi seeds flour as medium for indigenous lipase synthesis (Aspergillus niger M1407 lipase) by Solid-State Fermentation (SSF) showed good result for lipase and biodiesel industry development. This study aimed to characterize biodiesel synthesis using indigenous lipase from kesambi seeds. Experiments were carried out through five stages namely: oil extraction from kesambi seeds, purification of kesambi oil (degumming), extraction of A. niger M1407 lipase, trans-esterification and esterification activity of A. niger M1407 lipase assay and characterization of biodiesel. Biodiesel synthesis using A. niger M1407 lipase through esterification reaction produced biodiesel with an average acid number of 0.33 and 0.40 mg/g, water content 9.52 % and 10.47 % and density 0.7 g/mL. Biodiesel obtained from kesambi oil has lower acid numbers and densities but higher water content compared to Indonesian National Standard (SNI) value. Optimalization of the biodiesel kesambi oil synthesis could be done through adjusting ethanol and kesambi oil ratio and also by reducing water as a by-product of esterification reaction

Development of a bio-based bifunctional catalyst for simultaneous esterification and transesterification of neem seed oil: Modeling and optimization studies

High methanol/oil ratio together with reaction temperature with increase reaction time are some of the major drawbacks affecting the use of inorganic heterogeneous catalysts for simultaneous esterification and transesterification of oils. In this study, a novel bio-based bifunctional catalyst (BBFC) was prepared from sulfonated calcined corncobs and calcined poultry droppings by wet impregnation method. Characterization of the BBFC was done using X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Its catalytic activity in simultaneous esterification and transesterification of neem seed oil (NSO) having high free fatty acid content of 4.426% was investigated, with process parameters optimized using response surface methodology (RSM). Result revealed that the BBFC is highly bifunctional, possessing both acidic and basic oxides. Biodiesel yield of 92.89 wt% with an acid value of 0.23 mg KOH/g was obtained at optimum conditions of methanol/oil ratio, reaction temperature and time of 14.76:1, 61.90 °C and 72.65 min respectively using a catalyst loading of 2.58 wt%. The economic viability of the catalyst was also investigated and results shows that using recovered catalyst from the process gave a biodiesel yield of over 89 wt% after two successive cycles.

Efficient no‐glycerol biodiesel production using a novel biotemplated hierarchical porous‐structure CaO(O)

AbstractBACKGROUNDIn order to obtain an effective solid base with high surface area and hierarchical distribution of pore size, CaO(O) was synthesized via an exotemplating method, using radish as template and calcium acetate as precursor.RESULTSThe CaO(O) obtained by calcination of the impregnated biomorphic template demonstrated effective catalytic activity for the coupling transesterification of vegetable oil to produce biodiesel under mild reaction conditions using tri‐components (methanol, oil and methyl acetate) as resources. High yield of biodiesel, 98.6%, was obtained with a molar rapeseed oil/methyl acetate/methanol ratio of 1:1:8 under 65 °C at 2 h, which is greatly shorter than 6 h over commercial calcium oxide (CaO).CONCLUSIONVarious techniques including nitrogen physical adsorption, X‐ray diffraction (XRD), Fourier‐transform infrared (FTIR), thermogravimetric (TG), carbon dioxide‐chemical adsorption and morphology have been employed to characterize the samples. These results demonstrated that the synthesized CaO derived from plant template has a large surface area and various pore diameter distribution which cause hierarchical basic sites over the solid base. © 2020 Society of Chemical Industry

Melamine-based Covalent Organic Polymers (MCOPs) as Lipase Nanocarrier for Recyclable Esters Hydrolysis and Transesterification.

Present study has successfully synthesized melamine-based covalent organic polymers (MCOPs) and applied it as lipase carrier for recyclable esters hydrolysis and transesterification. The synthesized MCOPs are composed of dense nanosheet structures having a thickness of 3.5 nm. Three immobilization methods namely physical adsorption, cross-linking and carrier activation were employed to prepare the MCOPs-immobilized CRL. Cross-linked MCOPs-immobilized CRL (41.30 mg protein/g MCOPs) and carrier activated MCOPs-immobilized CRL (33.20 mg protein/g MCOPs) had higher enzyme loading as compared to physical absorb MCOPs-immobilized CRL (29.30 mg protein/g MCOPs). Nevertheless, physical absorb MCOPs-immobilized CRL demonstrated the highest esters hydrolysis (49.85 U) and transesterification (1.04 U) activities. Despite having the highest enzymatic activity, physical absorb MCOPs-immobilized CRL were not able to maintain its catalytic stability with more than 30% decreased in enzymatic activity during consecutive hydrolysis and transesterification activities. Meanwhile, cross-linked MCOPs-immobilized CRL demonstrated highest catalytic stability with highest enzymatic activities at the end of consecutive reactions. All the MCOPs-immobilized CRL can be easily recovered and reused through centrifugation with more than 85% of recovery rate.

FTIR spectroscopy analysis for monitoring biodiesel production by heterogeneous catalyst

Layered double hydroxides, mixed oxides, and pure oxides based on magnesium and calcium were evaluated as catalysts in the methyl transesterification of soybean oil in a batch reactor. The catalysts were prepared by continuous co-precipitation and characterized by specific surface area, thermogravimetric analysis, temperature-programmed desorption of CO2, and X-ray diffraction. The reactions were performed at 65 °C, methanol-to-oil molar ratio 9:1, catalyst dosage of 1 wt.%, and reaction time of 240 min. The biodiesel analysis was carried out by Fourier Transform Infrared spectroscopy (FTIR) and Gas Chromatography (GC). Calcium-based catalyst, pure oxide (CaO) and mixed oxide (CaAl), demonstrated higher activity for methyl transesterification than magnesium-based catalyst. Considering both groups of catalysts, the activity for transesterification was: pure oxide > mixed oxide >> LDH. These results were related to the strength of the basic sites. FTIR and GC results were similar, with the advantage of FTIR analysis being simple, fast, and economical.

New route for the synthesis of silica-supported calcium oxide catalyst in biodiesel production

This research aims to investigate the role of silica as a support for CaO catalyst in 4 different aspects: determination of optimum parameters, tolerance of water and FFA content, leaching and kinetics evaluation, and reusability of catalyst. Silica was extracted from rice husk by ion exchange method and subsequently impregnated with CaO. The experimental results showed that the supported catalysts exhibit excellent catalytic activity in transesterification of waste cooking oil with high yield of biodiesel, comparable to that of CaO catalyst. This is due to the fact that catalyst with higher surface area produces higher biodiesel yield. The presence of water did not have significant effect on the performance of supported catalysts, as silica can act as catalyst to esterify the FFA. Furthermore, silica support offered the greatest extent of leaching minimization of CaO and it has been proved that the calcium leached species was insignificant in transesterification reaction. Reusability study suggests that the synthesized catalysts can be recycled up for 8 successive runs. In conclusion, employing calcium rich wastes derived CaO impregnated with silica as catalyst showed good potential in catalytic applications with high economic benefits.