title: Enzymatic synthesis of rose aromatic ester (2-phenylethyl acetate) by lipase.
abstract: BACKGROUND
  2-Phenylethyl acetate (2-PEAc) is a highly valued natural volatile ester with a rose-like odour that is widely used to add scent or flavour to cosmetics, soaps, foods and drinks. In this study, 2-PEAc was synthesised enzymatically by transesterification of vinyl acetate with 2-phenethyl alcohol catalysed by immobilised lipase (Novozym(®) 435) from Candida antarctic
  
  
  RESULTS
  Response surface methodology and a three-level/three-factor Box-Behnken design were used to evaluate the effects of time, temperature and enzyme amount on the molar conversion % of 2-PEAc. The results showed that temperature was the most important variable. Based on the ridge max analysis results, optimum enzymatic synthesis conditions were predicted as a reaction time of 79 min, a temperature of 57.8 °C and an enzyme amount of 122.5 mg. The predicted and experimental yields were 86.4 and 85.4% respectively.
  
  
  CONCLUSIONS
  Three immobilised lipases were screened and 15 reaction conditions were tested in order to find the combination for maximum yield. The optimisation of 2-PEAc synthesis catalysed by Novozym(®) 435 was successfully developed. The kinetic study of this transesterification reaction showed that it followed an ordered ping-pong bi-bi mechanism without any inhibition by reactants.
authors.affiliation: Biotechnology Center, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 402, Taiwan.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kuo
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Chiang
authors.forename: Hen-Yi
authors.initials: HY
authors.lastname: Ju
authors.forename: Yu-Min
authors.initials: YM
authors.lastname: Chen
authors.forename: Ming-Yuan
authors.initials: MY
authors.lastname: Liao
authors.forename: Yung-Chuan
authors.initials: YC
authors.lastname: Liu
authors.forename: Chwen-Jen
authors.initials: CJ
authors.lastname: Shieh
mesh_terms: D000085:Acetates / Q000138:chemical synthesis*; D002175:Candida / Q000201:enzymology*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D004951:Esterification; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D009812:Odorants; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D027826:Rosa / Q000737:chemistry*; D013696:Temperature
chemical_list: D000085:Acetates; D004800:Enzymes, Immobilized; C054590:2-phenylethyl acetate; D008049:Lipase; D010626:Phenylethyl Alcohol