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Immobilized Candida Antarctica B Lipase Catalyzed Synthesis of Medium Chain Diacyglycerol and Sucrose Ester

Author: HuDanJing
Tutor: XiaYongMei
School: Jiangnan University
Course: Applied Chemistry
Keywords: Diglyceride Lauric acid sucrose ester Esterification Glycerolysis Enzyme
CLC: O621.36
Type: Master's thesis
Year: 2011
Downloads: 117
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Abstract

Fatty acid polyol ester as a safe, stable and efficient food additives, the synthesis methods and uses gradually research with emphasis on domestic and foreign scholars. Using immobilized Candida antarctica B lipase (Novozym 435) catalytic synthesis in carbon glycerol diester and lauric acid sucrose ester, and the effects of the factors of the main reaction, and to optimize the synthesis process. The main contents and results are as follows: 1. Caprylic acid, glycerol as substrate, caprylic acid diglyceride Novozyme 435 using immobilized Lipase-catalyzed synthesis of the direct esterification method. Found that a hydrophobic solvent to the synthesis of the impact of the diglyceride, the high log P petroleum ether beneficial product glycerol diester content increased; metal ions does not affect the catalytic activity of the lipase in the present system; different affect performance of the initial amount of water added to the esterification reaction in the initial reaction rate changes, and the amount of water added 5% glycerol (w / w) initial velocity; reaction system in the open area of ??29 mm diameter reactor esterification The highest rate, and without further added 4? molecular sieve dehydration; another suitable reaction temperature and substrate molar ratio can improve the the octoate conversion rate and the content of glycerin in the product. Optimized batch autoclave reactor caprylic diglyceride synthesis optimum conditions for the n (octoate): n (glycerol) = 2:1, the initial amount of water added 5% glycerol (w / w), plus the amount of enzyme 250 U / g bitterness, exposure (d = 29 mm), 60 oC, reaction for 10 h, the bitterness conversion rate of 94.21%, the products bitterness diacylglycerol 45.07%, its yield was 43.76%. Also found that microwave radiation may accelerate octoate and glycerol esterification reaction rate of up to 1.56 times, but no obvious promotion caprylic diglyceride generated. Obtained from a desired object of the high octylate diacylglycerol, the lower the efficiency of the batch tank reactor. 2 for the low efficiency problem of the batch tank reactor, selected in the packed column reactor through the lipase-catalyzed synthesis of the direct esterification method caprylic diglyceride, and examines the factors of the main reaction. Found 65 oC octylate glycerol molar ratio of 2 to 200 U / g octanoic acid catalyzed by lipase, and 10% glycerol (w / w) of the initial water addition, the volume flow rate of 34 h-1, 65 oC reaction 7 h, caprylic conversion The highest rate of up to 82.30%, the diglyceride content of 77.26%, the yield was 65.33%. And lipase can be reused 15 times and yet live. This fully proves that the bitterness diacylglycerol synthesis reactor packed column is more conducive than intermittent tank reactor. Further, the results of this study is currently using a packed column reactor to obtain the best results, the product not only high content of caprylic acid diglyceride, but also greatly reduces the amount of the lipase, and significantly reduce the cost of the reaction, the industrial application of the enzyme-catalyzed reaction bring a greater possibility. 3 further take into account the price of raw materials and reaction economics, this paper studied the lipase-catalyzed Sim capric triglyceride (GTCC) glycerol solution synthesis of carbon chain diacylglycerol. Found that only when the solvent is to promote the solvent tert-butanol, GTCC conversion rate significantly increased, the product oct capric acid diglyceride content is also significantly improved; also investigated the influence of other factors on the glycerolysis reaction, optimal conditions for GTCC and glycerol substrate molar ratio of 2, an initial amount of water added 4% (w / w, glycerol), tert-butanol and glycerol molar ratio is 2.1, Novozym 435 enzyme is added to the amount of 250 U / g of GTCC 65 oC for 24 h. , GTCC conversion rate was 74.21%, the diglyceride content in the product was 53.17%. Another first introduced in the microwave radiation used to accelerate the decomposition reaction of glycerol speed and found that the reaction under microwave irradiation under heating, an increase of 1.89 times faster than conventional, a significant increase in the diglyceride content in the product. This paper explored the enzymatic synthesis of lauric acid sucrose ester. With sucrose laurate, as a substrate, under different conditions, with immobilized Novozym 435 lipase-catalyzed Synthesis of lauric acid sucrose ester, and by thin layer chromatography combined with mass spectrometry analysis of the product composition. By examining the impact of various factors on the esterification reaction, optimization and optimal conditions for sucrose and lauric acid substrate, tert-butanol 2.92 (w / w substrate), 0.2 M borate buffer (pH 9.18) 4 % substrate (w / w), Lipase 1700 U-/ g sucrose, 65 oC under reaction for 24 h, the conversion rate was 22.17% lauric acid. In addition to study the effects of microwave radiation on lauric acid sucrose ester synthesis found that microwave radiation for 15 min compared to conventional heating, the reaction speed is 2.16 times faster, but with time, the the microwave effect slightly weakened.

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