Optimization of Enzymatically Prepared Hexyl Butyrate by Lipozyme IM-77

Hexyl butyrate, a green note flavour compound, is widely used in the food industry. The ability of immobilised lipase (Lipozyme IM-77) from Rhizomucor miehei to catalyse the transesterification of hexanol and tributyrin was investigated in this study. Response surface methodology (RSM) and five-level-five-factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time (2 to 10 h), temperature (25 to 65 °C), enzyme amount (10 to 50 %), substrate amount (in mol) ratio of tributyrin to hexanol (1:1 to 3:1), and added water content (0 to 20 %), on percentage amount (in mol) conversion of hexyl butyrate by transesterification. Reaction time and enzyme amount were the most important variables and substrate amount (in mol) ratio had less effect on the percentage of amount (in mol) conversion. Based on canonical analysis, the optimum synthesis conditions were: reaction time 8.3 h, temperature 50 °C, enzyme amount 42.7 %, substrate amount (in mol) ratio 1.8:1, and added water 12.6 %. The predicted value was 96.2 % and actual experimental value 95.3 % of the amount (in mol) conversion

Optimized ultrasound-assisted extraction of phenolic compounds from Polygonum cuspidatum

In this study the phenolic compounds piceid, resveratrol and emodin were extracted from P. cuspidatum roots using ultrasound-assisted extraction. Multiple response surface methodology was used to optimize the extraction conditions of these phenolic compounds. A three-factor and three-level Box-Behnken experimental design was employed to evaluate the effects of the operation parameters, including extraction temperature (30-70 °C), ethanol concentration (40%-80%), and ultrasonic power (90-150 W), on the extraction yields of piceid, resveratrol, and emodin. The statistical models built from multiple response surface methodology were developed for the estimation of the extraction yields of multi-phenolic components. Based on the model, the extraction yields of piceid, resveratrol, and emodin can be improved by controlling the extraction parameters. Under the optimum conditions, the extraction yields of piceid, resveratrol and emodin were 10.77 mg/g, 3.82 mg/g and 11.72 mg/g, respectively

Continuous Production of Lipase-Catalyzed Biodiesel in a Packed-Bed Reactor: Optimization and Enzyme Reuse Study

An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435) as a catalyst in a tert-butanol solvent system. Response surface methodology (RSM) and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature 52.1°C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were 83.31 ± 2.07% and 82.81 ± .98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis