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Biochemical Engineering Journal 97 (2015) 2531

Contents lists available atScienceDirect

Biochemical Engineering Journal

j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / b e j

Kinetics of enzymatic synthesis of monoferuloyl glycerol anddiferuloyl glycerol by transesterification in [BMIM]PF6

Shangde Sun , Xiaowei Chen

Lipid Technology and Engineering, School of Food Science and Engineering, Henan University of Technology, Lianhua Road, Zhengzhou 450001, Henan

Province, PR China

a r t i c l e i n f o

Article history:

Received 28 October 2014Received in revised form 26 January 2015

Accepted 1 February 2015

Available online 3 February 2015

Keywords:

Monoferuloyl glycerol

Diferuloyl glycerol

Enzymatic transesterification

Ethyl ferulate

Kinetics

Reaction mechanism

[BMIM]PF6

a b s t r a c t

Feruloyl glycerols (FGs), water-soluble glycerides (monoferuloyl glycerol (MFG) and diferuloyl glycerol(DFG)) of ferulic acid, can be used as natural ultraviolet (UV) filters and antioxidants in chemical, food,

pharmaceuticals, and drug industries. In order to promote the synthesis of FGs, the effect of processparameters, optimization, thermodynamic and kinetic properties on the enzymatic transesterification

of ethyl ferulate (EF) with glycerol in [BMIM]PF6 were investigated. The maximum yields of MFG(63.721.26%) and DFG (78.802.09%) were achieved at low glycerol concentrations in [BMIM]PF6.

The activation energies for EF conversion and transesterification to form MFG and DFG were calculatedas 40.16, 31.43 and85.38kJ/mol, respectively, based on the Arrhenius law. Reaction kinetics agreed with

the PingPong BiBi mechanism with the inhibitions of EF and glycerol. The enzymatic mechanism ofthe transesterification of EF with glycerol in [BMIM]PF 6was also proposed.

2015 Elsevier B.V. All rights reserved.

1. Introduction

Ferulic acid (4-hydroxy-3-methoxy cinnamic acid, FA) is a phe-nolic component of the cinnamic acid family found ubiquitouslythroughout the plant kingdom, which can be used as a potential

all-natural UV absorbent and antioxidant in food, health, cosmetic,and pharmaceutical industries[14]. Feruloyl glycerols (FGs) arethenaturalderivatives ofFA, which arewidely used asUV absorbersand antioxidants in many commercial applications (such as, cos-

metics, pharmaceuticals, and food industries)[57]. However, it isdifficult to separate FGs from natural raw materials since the con-tents of monoferuloyl glycerol (MFG) and diferuloyl glycerol (DFG)arevery low(

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26 S. Sun, X. Chen / Biochemical Engineering Journal 97 (2015) 2531

Scheme 1. Enzymatic synthesis of FGs by the transesterification of EF with glycerol in [BMIM]PF6.

2. Materials and methods

2.1. Materials

Ethyl ferulate (purity >99%) was purchased from Suzhou ChangTong Chemical Co., Ltd.(Suzhou, China). Glycerol (purity >99%) was

from Tianjin Ke Mi Ou Chemical Co., Ltd. (Tianjin, China). Novozym435 (Candida antarctica lipase immobilized on polyacrylic resin,with an activity of 7000 U/g solid enzyme, where one unit (U) ofactivity is defined as the amount of enzyme, which can catalyze thetransformationof1mol substrate perminute understandard con-

ditions) was provided by Novozymes A/S (Bagsvaerd, Denmark).1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6)was obtained from Henan Lihua Pharmaceutical Co., Ltd. (Anyang,China). Methanol and glacial acetic acid were of HPLC grade. All

other solvents were of analytical grade.

2.2. General procedure for enzymatic reaction in [BMIM]PF6

Reactions were performed in 25-ml round-bottom flasks, and

EF (0.33 g), glycerol (0.14 g), immobilized Novozym 435 (225 mg),and 3.35 mL [BMIM]PF6 were added. The reactants (0.47 g) weremixed by a magnetic stirrer (200 rpm) at 80 C under 10 mm Hgvacuum. These conditions were used throughout the experimentsexcept when otherwise stated in the text.

2.3. Kinetics study

Taking into account the results obtained in the experimen-tal designs, the thermodynamics properties and the Arrhenius

equation were acquired from the plot of reaction rate againsttemperature. EF conversion was used to determine the maximumreaction rate (vmax), MichaelisMenten constants (KM), and inhi-bition constants (Ki). The initial reaction rates (v0), defined as the

initial EFconversion perunit time (v0, mol/(Lmin)),werecalculatedfrom six experimental points of the yield-time profile correspond-ing to the first 0.5 h of the reaction (20.0% or less EF conversion),where the profiles were found to be approximately linear.

2.4. HPLC analysis

Reactants and products were analyzed by HPLC (Waters 1525)with a C18 reverse phase column (5m, 250mm4.6 mm) fittedwith a dual absorbance detector (Waters 2487) at 35 C, and eluted

with a binary gradient of solvent A (water, 0.5% v/v glacial aceticacid) and solvent B (methanol) at 1 mL/min. The elution sequenceconsisted, consecutively, of a linear gradient from 20% (v/v) B to

85% B (v/v) over 24 min, then to 20% B for 6 min, followed by 20%

B for 4min. The eluate was monitored at 325nm. The FGs wereidentified as described previously[9,22,23].

2.5. Statistical analyses

Response surface methodology (RSM) was employed in the

work. The mathematical relationship relating the variables to theresponses can be calculated by the quadratic polynomial equation(from BoxBehnken design):

Y= o +

4

i=1

iXi +

4

i=1

iiX2i +

3

i=1

4

j=i+1

ijXiXj (1)

whereYis one of the two responses;Xi and Xj represent the inde-pendent variables;ois the constant,ithe linear term coefficient,

iithe quadratic term coefficient, andijthe cross term coefficient.Triplicate experiments were carried out for each parameter

investigated. Results were expressed as averageS.E.M. The dif-ferences in mean values were evaluated by analysis of variance(two-way ANOVA) method. Statistical significance was considered

asp < 0.05.

3. Results and discussion

3.1. Effect of reaction temperature

In Fig. 1A, MFG and DFG yields slightly increased with theincreasing of temperature (

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S. Sun, X. Chen / Biochemical Engineering Journal 97 (2015) 2531 27

Fig. 1. Effect of reaction temperature on yields of MFG and DFG (A), and EF con-

version (B), and the relationship between the initial reaction rate ( v0) and reaction

temperature(C).The activationenergywas calculated bymultiplyingtheslopeof the

Arrhenius plots with the gas constant (8.314J/(mol K)). Reaction conditions: molarratioof glycerol toEF was 1:1, EFconcentration0.40mol/L, Novozym 435 60mg/ml,

vacuum pressure 10mmHg, 200rpm, and 14 h.

sites for acyl-enzyme complex formation, increase the probabil-ity of enzyme-substrate collision and subsequent reaction, andenhance higher reaction rate [24]. However, when the enzymeconcentration was above 60 mg/mL, the excessive enzyme parti-

cles were clustered, which reduced the accessibility of enzymeparticles to reactants and enhanced the external mass transferresistance[25]. A linear relationship between the initial reactionrate (v0) and enzyme concentration was achieved (Fig. 2B), and

can be expressed as: v0 = 0.1149Ccat. Where Ccat is enzyme con-centration. The results indicated that the transesterification waskinetically controlled.

3.3. Effect of substrate concentration

The effects of EF concentration on EF conversion and FGs yields

were shown inFig. 3. At lower EF concentrations (

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Fig. 4. Effect of molar ratio of glycerol to EF on EF conversion and yields of MFG

and DFG. Reaction conditions: Novozym 435 60mg/ml, 80 C, vacuum pressure

10mmHg, 200rpm, and 14h.

for DFG increased with the increase of EF concentration, and the

maximum DFG yield (76.982.83%) was obtained at 0.5:1 (molarratio of glycerol to EF) (Fig. 4).

3.4. Model fitting and verification

Response surface methodology (RSM) was employed in thework to obtain empirically significant (p < 0.05)models for thesyn-

thesis of MFGand DFG. Accordingto thestatistical method,the datawere analyzed employing a multiple regression technique to eval-uate the true relationship between the factors and EF conversions,MFG and DFG yields (Tables 1 and 2). And quadratic regression

models are given as follows.

(I) For MFG preparation

EF conversion(%) = 11.25X1 +5.90X2 12.60X3 +8.62X4 4.56X1X2 7.22X1X3 3.41X1X4 7.45X2X3 4.16X2X4 +4.86X3X4

7.47X122.67X2

224.47X3

25.24X4

2+92.61R2 = 0.9404 (2)

MFG yield(%) = 1.26X1 +0.86X2 +8.31X3 +3.90X4 2.05X1X2 +4.95X1X3 1.06X1X4 1.83X2X3 +0.72X2X4 +7.41X3X4

4.86X121.04X2

227.62X3

25.19X4

2+62.68R2 = 0.9353 (3)

(II) For DFG preparation

EF conversion(%)=2.20X1 2.48X2 +35.16X3 0.93X1X2 +0.77X1X3 +0.84X2X3 2.86X121.95X2

231.71X3

2+95.04R2 =0.9901

(4)

DFG yield(%) = 4.74X1 0.023X2 +9.16X3 1.12X1X2 +2.36X1X3 +2.38X2X3 5.50X125.70X2

242.93X3

2+77.53R2 = 0.9919

(5)

where X1, X2, X3, and X4 represent reaction time (h), tempera-ture (C), molar ratio of glycerol to EF, and enzyme concentration

(mg/mL), respectively.For MFG preparation, the maximum MFG yield (63.721.26%)

and EF conversion (98.261.05%) were achieved under the opti-malconditions:8.6 h, 68.5 mg/mL enzymeconcentration,1:1 molar

ratio of glycerol to EF, and 70 C, which were agreed with the pre-dicted values (63.38% MFG yield and 97.91% EF conversion). ForDFG preparation, the maximum DFG yield (78.802.09%) and EFconversion (99.240.60%) were achieved at 0.62:1 mole ratio of

glycerol to EF,90.6 C, 60.0 mg/mL enzymeconcentration for13.4 h,which were also agreed with the predicted values (79.03% DFGyield and 99.85% EF conversion). These results indicated that the

validation of the quadratic regression model.

Fig. 5. Relationship between the initial reaction rate and substrates (EF and glyc-

erol) concentrations, and the LineweaverBurk plot for Novozym 435 catalyzed the

transesterification of glycerol (dotted line a) with EF (dotted line b) in [BMIM]PF6.

Reactionconditions:Novozym435 60mg/ml,80

C,vacuumpressure10 mmHg, and200rpm.

In thework,the DFGyield(78.802.09%) wasmuch higherthanthat (45%) of previous report[11]. These results can be ascribed tothe molecular sieve role of [BMIM]PF6, which can drag out DFGfrom hydration layer of Novozym 435 into [BMIM]PF6 . Compared

with free-solvent (10:1, mole ratio of glycerol and EF) and organicsolvent (85:1, mole ratio of glycerol and FA) [9,10], a higherEF con-version (100%) was obtained in [BMIM]PF6 at the lower molarratio (1:1) of glycerol to EF, which may be attributed to the sol-

vation of [BMIM]PF6as solvents. Compared withp-toluenesulfonicacid, a high DFG yield (78.802.09%) wasobtained using Novozym

435 as catalyst in [Bmim]PF6, which may be attributed to the 1,3-

selectivity of Novozym 435. Similar result was also found in thesynthesis of diacylglycerols using Novozym 435 as catalyst[27].

3.5. Kinetics and reaction mechanism of the transesterification

As observed inFig. 5, when EF concentration (A) increased, bykeeping glycerol concentration (B) constant, the initial reactionrate (v0) increased proportionally and reached a maximum at acritical concentration. A subsequent increase in EF concentration

led to a decrease of v0. The effect of glycerol concentration on v0was similar to that of EF concentration. The LineweaverBurk plotsrevealed that the enzymatic transesterification of EF with glyc-

erol was accorded with classical MichaelisMenten kinetics, and

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Table 1

Experimental design and results of EF conversion and MFG yield as affected by reaction time, reaction temperature, substrate ratio and enzyme concentration.

Treament no.a Reaction timeX1(h)

Reaction temperature

X2 (C)

Substrate ratiob

X3 (mol/mol)

Enzyme concentration

X4 (mg/mL)

EF conversion (%) MFG yield (%)

1 4 90 1.0 60 83.452.01 60.911.93

2 4 80 1.0 40 58.621.29 46.101.37

3 8 80 1.0 60 93.423.0 63.062.99

4 8 80 1.0 60 92.031.69 62.981.39

5 8 90 1.0 80 96.852.01 63.381.37

6 8 90 1.0 40 90.144.70 53.563.017 12 70 1.0 60 90.752.58 58.191.93

8 12 80 1.0 40 90.081.60 55.392.38

9 8 80 1.0 60 92.462.01 62.261.38

10 8 80 1.0 60 92.622.58 62.152.8611 8 80 1.5 80 63.503.10 51.061.37

12 8 80 1.0 60 92.522.31 62.940.39

13 12 90 1.0 60 99.203.11 61.651.82

14 12 80 1.0 80 98.021.99 59.902.12

15 4 80 0.5 60 56.851.82 30.271.26

16 8 90 1.5 60 49.870.79 39.350.37

17 8 80 1.5 40 31.841.07 27.841.28

18 8 70 1.0 40 60.442.91 46.672.68

19 4 80 1.0 80 80.202.16 54.842.30

20 12 80 0.5 60 89.311.08 15.911.02

21 8 70 0.5 60 69.831.58 27.901.5222 8 90 0.5 60 81.171.22 20.790.38

23 4 80 1.5 60 42.680.90 30.282.09

24 8 80 0.5 80 84.361.58 18.501.9225 4 70 1.0 60 56.771.02 49.240.97

26 8 80 0.5 40 72.162.66 24.911.57

27 8 70 1.0 80 83.801.02 53.591.58

28 8 70 1.5 60 68.322.00 53.780.79

29 12 80 1.5 60 46.241.68 35.741.08

a Numbers were run in random order.b Glycerol/EF (mol/mol).

Table 2

Experimental design and results of EF conversion and DFG yield as affected by reaction time, reaction temperature, and substrate ratio.

Treament no.a Reaction timeX1(h)

Reaction temperature

X2(C)

Substrate ratiob X3(mol/mol)

EF conversion (%) DFG yield (%)

1 8 90 1.0 97.58 3.10 35.20 1.92

2 16 90 0.1 21.82 2.79 18.26 1.08

3 12 80 0.1 34.83 0.28 23.28 0.284 12 90 0.55 94.92 1.26 76.89 1.00

5 12 100 1.0 89.61 0.38 39.28 0.28

6 12 90 0.55 95.26 1.36 78.51 1.62

7 16 80 0.55 95.47 1.99 75.11 2.91

8 12 80 1.0 97.45 3.01 33.01 0.79

9 12 90 0.55 94.78 2.81 76.76 1.9310 16 90 1.0 99.72 1.78 45.14 1.82

11 12 90 0.55 95.42 2.08 78.89 1.03

12 12 90 0.55 94.83 0.98 76.58 2.80

13 8 100 0.55 86.85 1.67 59.78 0.93

14 12 100 0.1 23.63 2.81 20.02 0.01

15 8 80 0.55 85.39 0.87 59.13 1.98

16 8 90 0.1 22.78 1.99 17.77 1.72

17 16 100 0.55 93.21 1.72 71.27 1.07

a Numbers were run in random order.b Glycerol/EF (mol/mol).

enzyme activity was inhibited by both EF and glycerol at theirhigher concentrations. Therefore, the enzymatic transesterifica-tion can be modeled using the PingPong BiBi kinetic mechanism

with the inhibitions of EF and glycerol at higher concentrations[25,28,29]. The initial reaction rate can be expressed as follows:

v0 =vmax[A][B]

KMA[B](1+([B]/KiB))+ KMB[A](1+([A]/KiA))+[A][B]

where, v0is the initial reaction rate; vmaxis the maximum reaction

rate; [A] and [B] are the initial concentrations of EF and glycerol,respectively;KMAandKMBare Michaelis constants for EF and glyc-erol,respectively; KiAand KiBarethe inhibition constants forEF and

glycerol, respectively.

Initial reaction rates were calculated from the linear por-tion of the concentrationtime profiles, and the kinetic constantscan be obtained by non-linear regression analysis for the above

model [30]. Results showed that vmax, KMA, and KMB were12.01 mol/(Lmin), 0.23 mol/L, and 0.42mol/L, respectively, whichindicated that the affinity between enzyme and EF is higherthan that of enzyme and glycerol. KiA and KiB were 1.20 mol/L

and 0.48 mol/L, respectively, which were attributed to a glycerolhindrance layer formed in the enzyme micro-environment andelectron-donating and steric hindrance of EF[28,31].

Based on PingPong BiBi mechanism with the inhibitions of EF

andglycerol,the transesterificationmechanism forthe synthesis of

FGs was proposed as follows (Fig. 6): (i) the acyl donor, EF, is firstly

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Fig. 6. Reaction mechanism for the transesterification of EF with glycerol to form MFG and DFG.

binded to enzyme (E) to form a non-covalent enzymeester com-plex (EFE); and EFE complex is transferred to the acylenzyme

complex (FE) with the release of ethanol, or EFE is hydrolyzedto form FA and ethanol; (ii) glycerol is combined with FE to formanother complex ([FE]glycerol),and [FE]glycerol is isomerizedto the esterenzyme complex (MFGE), and then MFGE complex

releasesE toformthe first product MFG (1);(iii) MFG isbindedwithanother FE to form the MFG[FE] complex, and the MFG[FE]

complex is isomerized to the DFGE complex, and then the DFGEcomplex releases E to form the second product DFG (2). However,

at higher glycerol concentrations, the dead-end binary complex(glycerolE) between glycerol and enzyme is formed instead of theEFE (3).In contrary,at higherEF concentrations,another dead-endcomplex (FEEF) between EF and enzyme is formed instead of the

[FE]glycerol (4).

4. Conclusions

Enzymatic synthesis of FGs by the transesterification of EF withglycerol catalyzed by Novozym 435 were successfullyperformed in

[BMIM]PF6. Under the optimized conditions, the maximum yieldsof MFG and DFG were 63.721.26% and 78.802.09% at 1:1 and

0.62:1 molar ratio of glycerol to EF, respectively. Due to the 1,3-selectivity of Novozym 435 and the molecular sieve effect of the

[BMIM]PF6, it was found to be beneficial to reduce the amount ofglycerol in the substrates. The two-step transesterificationreactionkinetics, first to form MFG, and then to form DFG, was agreed withPingPongBiBimechanismwith theinhibitions of EF andglycerol.

Compared with glycerol, EF showed a higher affinity to Novozym435.

Acknowledgements

The authors gratefully acknowledge financial support from

National Natural Science Foundation of China (31101301),FundingScheme for Young Teachers in Colleges and Universities in Henan

Province (2012GGJS-83), and Plan for Scientific Innovation Talentof Henan University of Technology (11CXRC03).

References

[1] A. Saija, A. Tomaino, R.L. Cascio, D. Trombetta, A. Proteggente, A.D. Pasquale,N. Uccella, F. Bonina, Ferulic and caffeic acids as potential protective agentsagainst photooxidative skin damage, J. Sci. Food Agric. 79 (1999) 476480.

[2] H. Kikuzaki, M. Hisamoto, K. Hirose, K. Akiyama, H. Taniguchi, Antioxidantproperties of ferulic acid and its related compounds, J. Agric. Food Chem. 50(2002) 21612168.

[3] P. Torre, B. Aliakbarian, B. Rivas, J.M. Domnguez, A. Converti, Release offerulic acid from corn cobs by alkaline hydrolysis, Biochem. Eng. J. 40 (2008)500506.

[4] J. Rencoret, E. Aracri, A. Gutirrez, J.C. Ro, A.L. Torres, T. Vidal, A.T. Martnez,Structural insights on laccase biografting of ferulic acid onto lignocellulosicfibers, Biochem. Eng. J. 86 (2014) 1623.

[5] Z.M.F. Freitas, J.C.S. Goncalves, E.P. Santos, A. Vergnanini, Glyceridic esters ofp-methoxycinnamic acid. A new sunscreen of the cinnamate class, Int. J.Cosmetic Sci. 23 (2001) 147152.

[6] J.A. Laszlo, K.O. Evans, K.E. Vermillion, M. Appell, Feruloyl dioleoylglycerolantioxidant capacity in phospholipid vesicles, J. Agric. Food Chem. 58 (2010)58425850.

[7] D.L. Compton, J.A. Laszlo, K.O. Evans, Antioxidant properties of feruloylglycerol derivatives, Ind. Crops Prod. 36 (2012) 217221.

[8] J. Graca, H. Pereira, Suberin structure in potato periderm: glycerol, long-chainmonomers, and glyceryl and feruloyl dimers, J. Agric. Food Chem. 48 (2000)54765483.

[9] S. Sun, L. Shan, Q. Jin, Y. Liu, X. Wang, Solvent-free synthesis of glycerylferulate using a commercial microbial lipase, Biotechnol. Lett. 29 (2007)945949.

[10] T. Matsuo, T. Kobayashi, Y. Kimura, M. Tsuchiyama, T. Oh, T. Sakamoto, S.Adachi, Synthesis of glyceryl ferulate by immobilized ferulic acid esterase,Biotechnol. Lett. 30 (2008) 21512156.

[11] S. Sun, F. Qin, Y. Bi, J. Chen, G. Yang, W. Liu, Enhanced transesterification ofethyl ferulate with glycerol for preparing glyceryl diferulate using a lipase inionic liquids as reaction medium, Biotechnol. lett. 35 (2013) 14491454.

[12] S. Sun, X. Chen, Y. Bi, J. Chen, G. Yang, W. Liu, Functionalized ionicliquid-catalyzed 1-feruloyl-sn-glycerol synthesis, J. Am. Oil Chem. Soc. 91(2014) 759765.

[13] D.L. Compton, J.A. Laszlo, 1, 3-Diferuloyl-sn-glycerol from the biocatalytictransesterification of ethyl 4-hydroxy-3-methoxy cinnamic acid (ethylferulate) and soybean oil, Biotechnol. Lett. 31 (2009) 889896.

[14] R.A. Holser, T.R. Mitchell, R.E. Harry-Okuru, S.F. Vaughn, E. Walter, D.Himmelsbach, Preparation and characterization of 4-methoxy cinnamoylglycerol, J. Am. Oil Chem. Soc. 85 (2008) 347351.

[15] S. Sun, G. Yang, Y. Bi, F. Xiao, Chemoenzymatic synthesis of feruloylatedmonoacyl-and diacyl-glycerols in i onic liquids, Biotechnol. lett. 31 (2009)18851889.

[16] M. Tsuchiyama, T. Sakamoto, T. Fujita, S. Murata, H. Kawasaki, Esterification offerulic acid with polyols using a ferulic acid esterase from Aspergillus niger,Biochim. Biophys. Acta 1760 (2006) 10711079.

[17] M. Moniruzzaman, K. Nakashima, N. Kamiya, M. Goto, Recent advances ofenzymatic reactions in ionic liquids, Biochem. Eng. J. 48 (2010)295314.

[18] V.I. Prvulescu, C. Hardacre, Catalysis in ionic liquids, Chem. Rev. 107 (2007)26152665.

[19] U. Kragl, M. Eckstein, N. Kaftzik, Enzyme catalysis in ionic liquids, Curr. Opin.Biotech. 13 (2002) 565571.

[20] E.R. Cooper, C.D. Andrews, P.S. Wheatley, P.B. Webb, P. Wormald, R.E. Morris,Ionic liquids and eutectic mixtures as solvent and template in synthesis ofzeolite analogues, Nature 430 (2004) 10121016.

[21] R. Xu, W. Zhang, J. Guan, Y. Xu, L. Wang, H. Ma, Z. Tian, X. Han, L. Lin, X. Bao,New insights into the role of amines in the synthesis of molecular sieves inionic liquids, Chem-Eur. J. 15 (2009) 53485354.

[22] S. Sun, X. Chen, Y. Bi, G. Yang, Selective separation of mono glyceryl ferulateusing water from an ionic liquid solution of enzymatic transesterification, J.Am. Oil Chem. Soc. 91 (2014) 13391345.

[23] D.L. Compton, J.A. Laszlo, M.A. Berhow, Identification and quantification offeruloylated mono- di-, and triacylglycerols from vegetable oils, J. Am. OilChem. Soc. 83 (2006) 753758.

[24] E.L. Soo, A.B. Salleh, M. Basri, R.N.Z.A. Rahman, K. Kamaruddin, Responsesurface methodological study on lipase-catalyzed synthesis of amino acidsurfactants, Process Biochem. 39 (2004) 15111518.

[25] G.D. Yadav, S. Devendran, Lipase catalyzed synthesis of cinnamyl acetate viatransesterification in non-aqueous medium, Process Biochem. 47 (2012)496502.

[26] L.A. Lerin, A. Richetti, R. Dallago, H. Treichel, M.A. Mazutti, J.V. Oliveira, O.A.C.Antunes, E.G. Oestreicher, D. Oliveira, Enzymatic synthesis of ascorbylpalmitate in organic solvents: process optimization and kinetic evaluation,Food Bioprocess Tech. 5 (2012) 10681076.

[27] D. Hu, J. Chen, Y. Xia, A comparative study on production of middle chaindiacylglycerol through enzymatic esterification and glycerolysis, J. Ind. Eng.Chem. 19 (2013) 14571463.

7/23/2019 1-s2.0-S1369703X1500025X-main

7/7


[28] W.P. Hong, J.Y. Park, K. Min, M.J. Ko, K. Park, Y.J. Yoo, Kinetics of glycerol effecton biodiesel production for optimal feeding of methanol, Kor. J. Chem. Eng. 28(2011) 19081912.

[29] V.V. Kuperkar, V.G. Lade, A. Prakash, V.K. Rathod, Synthesis of isobutylpropionate using immobilized lipase in a solvent free system: optimizationand kinetic studies, J. Mol. Catal. B: Enzym. 99 (2014) 143149.

[30] J. Huang, Y. Liu, Q. Jin, X. Wu, X. Wang, Z. Song, Enzyme-catalyzed synthesis ofmonoacylglycerols citrate: kinetics and thermodynamics, J. Am. Oil Chem.Soc. 89 (2012) 16271632.

[31] S. Sun, L. Shan, Y. Liu, Q. Jin, Y. Song, X. Wang, Solvent-free enzymaticsynthesis of feruloylated diacylglycerols and kinetic study, J. Mol. Catal. B:Enzym. 57 (2009) 104108.

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