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High yield of wax ester synthesized from cetyl alcohol and octanoic acid by lipozyme RMIM and Novozym 435.

Kuo CH, Chen HH, Chen JH, Liu YC, Shieh CJ - Int J Mol Sci (2012)

Bottom Line: Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) are employed to evaluate the effects of reaction time (1-5 h), reaction temperature (45-65 °C), substrate molar ratio (1-3:1), and enzyme amount (10%-50%) on the yield of cetyl octanoate.Using RSM to optimize the reaction, the maximum yields reached 94% and 98% using Lipozyme(®) RMIM and Novozym(®) 435, respectively.Novozym(®) 435 proves to be a more efficient biocatalyst than Lipozyme(®) RMIM.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Center, National Chung Hsing University, 250 Kuo-kuang Road, Taichung 402, Taiwan; E-Mail: jahomekuo@gmail.com.

ABSTRACT
Wax esters are long-chain esters that have been widely applied in premium lubricants, parting agents, antifoaming agents and cosmetics. In this study, the biocatalytic preparation of a specific wax ester, cetyl octanoate, is performed in n-hexane using two commercial immobilized lipases, i.e., Lipozyme(®) RMIM (Rhizomucor miehei) and Novozym(®) 435 (Candida antarctica). Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) are employed to evaluate the effects of reaction time (1-5 h), reaction temperature (45-65 °C), substrate molar ratio (1-3:1), and enzyme amount (10%-50%) on the yield of cetyl octanoate. Using RSM to optimize the reaction, the maximum yields reached 94% and 98% using Lipozyme(®) RMIM and Novozym(®) 435, respectively. The optimum conditions for synthesis of cetyl octanoate by both lipases are established and compared. Novozym(®) 435 proves to be a more efficient biocatalyst than Lipozyme(®) RMIM.

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Response surface plots showing the relationships between cetyl octanoate yield and reaction parameters for Lipozyme® RMIM: (a) reaction time and enzyme amount; (b) reaction time and temperature; (c) temperature and substrate molar ratio.
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f2-ijms-13-11694: Response surface plots showing the relationships between cetyl octanoate yield and reaction parameters for Lipozyme® RMIM: (a) reaction time and enzyme amount; (b) reaction time and temperature; (c) temperature and substrate molar ratio.

Mentions: Reaction times and enzyme amount were investigated in the range of the reaction time of 1–5 h and enzyme amount of 10%–50%, respectively. Figure 2a represents the effect of varying reaction time and enzyme amount on esterification efficiency at a substrate molar ratio of 2:1 and a reaction temperature of 55 °C. With the highest reaction time of 5 h, and the highest enzyme amount of 50%, a cetyl octanoate yield of 99% was obtained. Whereas, when the enzyme amount was decreased to 10% and the reaction time shortened to 1 h, only 42% yield remained. This result was consistent with that shown in Table 3, which indicated that both the reaction time and enzyme amount were the two most important parameters. Figure 2b shows the effects of reaction time, temperature and their mutual interaction on cetyl octanoate synthesis at a substrate molar ratio of 2:1 and an enzyme amount of 30%. At any given temperature from 45 °C to 65 °C, an increase in reaction time from 1 to 5 h led to a curvilinear increase in yield from ~50% to ~90%, indicating that the reaction time was one of the important factors in the synthesis of cetyl octanoate. However, the reaction temperature showed an insignificant effect on the yield. The effect of varying reaction temperature and substrate molar ratio on esterification at a reaction time of 3 h and an enzyme amount of 30% is shown in Figure 2c. At any given substrate molar ratio (octanoic acid:cetyl alcohol), the yield was not affected by reaction temperature, the difference in yield was less than 10%. The critical substrate molar ratio can be found around 2:1 (octanoic acid:cetyl alcohol) as shown in Figure 2c. When the substrate molar ratio increased by more than 2:1, a slight decrease in yield occurred. Chowdary et al. [27] observed the esterification rate of ethyl hexanoate catalyzed by Rhizomucor miehei lipase decreased at high hexanoic acid concentrations. Hari Krishna et al. [28] reported a competitive enzyme inhibition by butyric acid during esterification reactions catalyzed by Rhizomucor miehei lipase. Our result agreed well with their results. The reason that an increase of substrate molar ratio led to decreases in the yield might be due to inhibition of Rhizomucor miehei lipase activity by acidic reaction condition.


High yield of wax ester synthesized from cetyl alcohol and octanoic acid by lipozyme RMIM and Novozym 435.

Kuo CH, Chen HH, Chen JH, Liu YC, Shieh CJ - Int J Mol Sci (2012)

Response surface plots showing the relationships between cetyl octanoate yield and reaction parameters for Lipozyme® RMIM: (a) reaction time and enzyme amount; (b) reaction time and temperature; (c) temperature and substrate molar ratio.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472770&req=5

f2-ijms-13-11694: Response surface plots showing the relationships between cetyl octanoate yield and reaction parameters for Lipozyme® RMIM: (a) reaction time and enzyme amount; (b) reaction time and temperature; (c) temperature and substrate molar ratio.
Mentions: Reaction times and enzyme amount were investigated in the range of the reaction time of 1–5 h and enzyme amount of 10%–50%, respectively. Figure 2a represents the effect of varying reaction time and enzyme amount on esterification efficiency at a substrate molar ratio of 2:1 and a reaction temperature of 55 °C. With the highest reaction time of 5 h, and the highest enzyme amount of 50%, a cetyl octanoate yield of 99% was obtained. Whereas, when the enzyme amount was decreased to 10% and the reaction time shortened to 1 h, only 42% yield remained. This result was consistent with that shown in Table 3, which indicated that both the reaction time and enzyme amount were the two most important parameters. Figure 2b shows the effects of reaction time, temperature and their mutual interaction on cetyl octanoate synthesis at a substrate molar ratio of 2:1 and an enzyme amount of 30%. At any given temperature from 45 °C to 65 °C, an increase in reaction time from 1 to 5 h led to a curvilinear increase in yield from ~50% to ~90%, indicating that the reaction time was one of the important factors in the synthesis of cetyl octanoate. However, the reaction temperature showed an insignificant effect on the yield. The effect of varying reaction temperature and substrate molar ratio on esterification at a reaction time of 3 h and an enzyme amount of 30% is shown in Figure 2c. At any given substrate molar ratio (octanoic acid:cetyl alcohol), the yield was not affected by reaction temperature, the difference in yield was less than 10%. The critical substrate molar ratio can be found around 2:1 (octanoic acid:cetyl alcohol) as shown in Figure 2c. When the substrate molar ratio increased by more than 2:1, a slight decrease in yield occurred. Chowdary et al. [27] observed the esterification rate of ethyl hexanoate catalyzed by Rhizomucor miehei lipase decreased at high hexanoic acid concentrations. Hari Krishna et al. [28] reported a competitive enzyme inhibition by butyric acid during esterification reactions catalyzed by Rhizomucor miehei lipase. Our result agreed well with their results. The reason that an increase of substrate molar ratio led to decreases in the yield might be due to inhibition of Rhizomucor miehei lipase activity by acidic reaction condition.

Bottom Line: Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) are employed to evaluate the effects of reaction time (1-5 h), reaction temperature (45-65 °C), substrate molar ratio (1-3:1), and enzyme amount (10%-50%) on the yield of cetyl octanoate.Using RSM to optimize the reaction, the maximum yields reached 94% and 98% using Lipozyme(®) RMIM and Novozym(®) 435, respectively.Novozym(®) 435 proves to be a more efficient biocatalyst than Lipozyme(®) RMIM.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Center, National Chung Hsing University, 250 Kuo-kuang Road, Taichung 402, Taiwan; E-Mail: jahomekuo@gmail.com.

ABSTRACT
Wax esters are long-chain esters that have been widely applied in premium lubricants, parting agents, antifoaming agents and cosmetics. In this study, the biocatalytic preparation of a specific wax ester, cetyl octanoate, is performed in n-hexane using two commercial immobilized lipases, i.e., Lipozyme(®) RMIM (Rhizomucor miehei) and Novozym(®) 435 (Candida antarctica). Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) are employed to evaluate the effects of reaction time (1-5 h), reaction temperature (45-65 °C), substrate molar ratio (1-3:1), and enzyme amount (10%-50%) on the yield of cetyl octanoate. Using RSM to optimize the reaction, the maximum yields reached 94% and 98% using Lipozyme(®) RMIM and Novozym(®) 435, respectively. The optimum conditions for synthesis of cetyl octanoate by both lipases are established and compared. Novozym(®) 435 proves to be a more efficient biocatalyst than Lipozyme(®) RMIM.

Show MeSH
Related in: MedlinePlus