Green and efficient production of octyl hydroxyphenylpropionate using an ultrasound-assisted packed-bed bioreactor

A solvent-free system to produce octyl hydroxyphenylpropionate (OHPP) from p-hydroxyphenylpropionic acid (HPPA) and octanol using immobilized lipase (Novozym(A (R)) 435) as a catalyst in an ultrasound-assisted packed-bed bioreactor was investigated. Response-surface methodology (RSM) and a three-level-three-factor Box-Behnken design were employed to evaluate the effects of reaction temperature (x (1)), flow rate (x (2)) and ultrasonic power (x (3)) on the percentage of molar production of OHPP. The results indicate that the reaction temperature and flow rate were the most important variables in optimizing the production of OHPP. Based on a ridge max analysis, the optimum conditions for OHPP synthesis were predicted to consist of a reaction temperature of 65A degrees C, a flow rate of 0.05 ml/min and an ultrasonic power of 1.74 W/cm(2) with a yield of 99.25%. A reaction was performed under these optimal conditions, and a yield of 99.33 +/- A 0.1% was obtained

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Optimal formation of hexyl laurate by Lipozyme IM-77 in solvent-free system

A medium-chain ester, hexyl laurate, with fruity flavor is primarily used in personal care formulations as an important emollient for cosmetic applications. To conform to the "natural" interests of consumers, the ability of immobilized lipase from Rhizomucor miehei (Lipozyme IM-77) to catalyze the direct esterification of hexanol and lauric acid by using a solvent-free system was investigated in this study. Response surface methodology (RSM) and four-factor-five-level central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time (10-50 min), temperature (45-85 degrees C), lipase amount (10-30 mg/volume; 0.077-0.231 batch acidolysis units of Novo (BAUN), and pH memory (5-9), on percentage molar conversion of hexyl laurate by lipase-catalyzed direct esterification. Reaction time, temperature, and enzyme amount had significant effects on percent molar conversion. On the basis of ridge maximum analysis, the optimum synthesis conditions for hexyl laurate were a reaction time of 40.6 min, a temperature of 58.2 degrees C, an enzyme amount of 25.4 mg/volume (0.196 BAUN), and a pH memory of 5.9. The predicted percentage molar conversion of hexyl laurate was 69.7 +/- 1.4%

Optimum immobilization of Candida rugosa lipase on Celite by RSM

Immobilization of Candida rugosa lipase (lipase AY-30) by adsorption on Celite led to a markedly improved performance of the enzyme. Immobilization conditions and characterization of the immobilized enzyme were investigated. Lipase activity was measured with glycerol tributyrate as substrate. Response surface methodology (RSM) and 3-level-3-factor fractional factorial design were employed to evaluate the effects of immobilization parameters, such as immobilization time (30-90 min), immobilization temperature (0-20 degrees C), and enzyme/support ratio (0.3-0.5, w/w), on the specific activity of immobilized lipase. Based on the analysis of ridge max, the optimum immobilization conditions were as follows: immobilization time 59.1 min, immobilization temperature 10.7 degrees C, and enzyme/support ratio 0.5 (w/w); the highest specific activity obtained was 18.16 U/mg-protein with activity yield of 34.1%. (C) 2006 Elsevier B.V. All rights reserved

Optimal continuous biosynthesis of hexyl laurate by a packed bed bioreactor

Hexyl laurate, a medium-chain ester carried about fruity flavor, is primarily used in personal care formulations as an important emollient for cosmetic applications. On the basis of the hexyl laurate could be successfully synthesized by lipase within a batch system in our previous report. This study aimed to develop an optimal continuous procedure of lipase-catalyzed hexyl laurate synthesis in a packed-bed bioreactor to investigate the possibility of large-scale production further. The ability of lipase from Rhizomucor miehei (Lipozyme IM-77) to catalyze the direct-esterification of 1-hexanol and lauric acid in n-hexane was investigated. Response surface methodology (RSM) and 3-level-3-factor fractional factorial design were employed to evaluate the effects of synthesis parameters, such as reaction temperature (35-55 degrees C), mixture flow rate (1.5-4.5 mL/min) and substrate molar ratio 1-hexanol to lauric acid (1:1-1:3) on production rate (mu mol/min) of hexyl laurate by direct-esterification. Based on the analysis of ridge max, the optimum synthesis conditions for hexyl laurate were as follows: 45 degrees C of reaction temperature, substrate molar ratio 1:2 and reaction flow rate 4.5 mL/min. The optimum predicted production rate was 435.6 +/- 0.9 mu mol/min and the actual value was 437.6 +/- 0.4 mu mol/min. (c) 2007 Published by Elsevier Ltd

Optimal alpha-Chymotrypsin-Catalyzed Synthesis of N-Ac-Phe-Gly-NH2

N-Acetyl-phenylalanine-glycinamide (N-Ac-Phe-Gly-NH2), a type of dipeptide derivative, was synthesized from N-acetyl phenylalanine ethyl ester and glycinamide and catalyzed by alpha-chymotrypsin, a protease, in a biphasic system. Response surface methodology with a four-factor, five-level central composite rotatable design was employed to evaluate the effects of selected parameters that included incubation time, reaction temperature, enzyme activity, and pH level on the yield of the dipeptide derivative. The results indicated that pH significantly affected the yield of N-Ac-Phe-Gly-NH2 In a ridge max analysis, the optimum condition for this synthesis included an incubation time of 30.9 min, a reaction temperature of 35.8 degrees C, an enzyme activity of 159.2 U, and a pH of 8.98. The predicted and the actual (experimental) yields were 98.0 and 95.1%, respectively

Simultaneous purification and immobilization of D-hydantoinase on the immobilized metal affinity membrane via coordination bonds

This study constructs the immobilized metal affinity membrane (IMAM) via coupling of epichlorohydrin, iminodiacetic acid, and nickel ion on the regenerated cellulose membrane. The D-hydantoin-hydrolyzing enzyme (DHTase) harboring a poly-His tagged residue was used as a model protein immobilized on the prepared IMAM. Various immobilization conditions were examined based on the yield of N-carbamoyl-D-p-hydroxyphenylglycine in batch reactions. The immobilization conditions were studied and the optimal conditions are as follows. By employing an IMAM with nickel ion of 155.5 +/- 5 mu mol/disc immersed in 0.1 M Tris-HCl buffer pH 8 (with 0.8M sodium chloride) and immobilized time of 14h. a DHTase activity of 4.2 +/- 0.3 U/disc was obtained. The immobilized DHTase membrane can achieve a larger pH and thermal tolerant range than that of free enzyme. Meanwhile, the stability test showed that 99% of enzyme activity could be retained after being repeated 15-times. The storage test also displayed 99% enzyme preservation after 7 weeks of storage. (C) 2011 Elsevier B.V. All rights reserved

Optimized synthesis of lipase-catalyzed L-ascorbyl laurate by Novozymo (R) 435

L-Ascorbyl laurate is a fatty acid derivative Of L-ascorbic acid which can be widely used as a natural antioxidant in both lipid containing food and cosmetic applications. To avoid any possible harmful effects from chemically synthesized product, the enzymatic synthesis appears to be the best way to satisfy the consumer demand for natural antioxidants. The ability of immobilized lipase from Candida antarctica (Novozym (R) 435) to catalyze the direct esterification between L-ascorbic acid and lauric acid was investigated. Response Surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time (2-10h), temperature (25-65 C), enzyme amount (10-50% w/w of L-ascorbic acid), and substrate molar ratio of L-ascorbic acid to lauric acid (1:1-1:5) on percentage molar conversion to L-ascorbyl laurate. Based on the analysis result of ridge max, the optimal enzymatic synthesis conditions were predicted as follows: reaction time 6.7 h, temperature 30.6 C, enzyme amount 34.5%, substrate molar ratio 1:4.3: and the optimal actual yield was 93.2%. (C) 2008 Elsevier B.V. All rights reserved

Milk-clotting enzymes produced by culture of Bacillus subtilis natto

Factors affecting the production of milk-clotting enzyme (MCE) by Bacillus subtilis (natto) Takahashi, a ready available commercial natto starter, were studied. Remarkable milk-clotting activity (MCA), 685.7 SU/ml or 12,000SU/g, was obtained when the bacteria were cultivated in (lie medium containing sucrose (50g/L) and basal salts at pH 6,37 C with shaking at 175 rpm for 1 day. The MCA and MCA/PA ratio of the crude enzyme obtained are comparable with those of Pfizer microbial rennin and Mucor rennin. The crude enzyme showed excellent pH and thermal stability: it retained 96% of MCA after incubation for 40 min at 40 C and retained more than 80% of its activity between pH 4 and pH 7 for more than 30 min at 30 C. The MCE of B. subtilis (natto) Takahashi has potential as calf rennet substitutes. (C) 2008 Elsevier B.V. All rights reserved