Continuous Production of 2-Phenylethyl Acetate in a Solvent-Free System Using a Packed-Bed Reactor with Novozym® 435

Abstract

2-Phenylethyl acetate (2-PEAc), a highly valued natural volatile ester, with a rose-like odor, is widely added in cosmetics, soaps, foods, and drinks to strengthen scent or flavour. Nowadays, 2-PEAc are commonly produced by chemical synthesis or extraction. Alternatively, biocatalysis is a potential method to replace chemical synthesis or extraction for the production of natural flavour. Continuous synthesis of 2-PEAc in a solvent-free system using a packed bed bioreactor through immobilized lipase-catalyzed transesterification of ethyl acetate (EA) with 2-phenethyl alcohol was studied. A Box–Behnken experimental design with three-level-three-factor, including 2-phenethyl alcohol (2-PE) concentration (100–500 mM), flow rate (1–5 mL min−1) and reaction temperature (45–65 °C), was selected to investigate their influence on the molar conversion of 2-PEAc. Then, response surface methodology and ridge max analysis were used to discuss in detail the optimal reaction conditions for the synthesis of 2-PEAc. The results indicated both 2-PE concentration and flow rate are significant factors in the molar conversion of 2-PEAc. Based on the ridge max analysis, the maximum molar conversion was 99.01 ± 0.09% under optimal conditions at a 2-PE concentration of 62.07 mM, a flow rate of 2.75 mL min−1, and a temperature of 54.03 °C, respectively. The continuous packed bed bioreactor showed good stability for 2-PEAc production, enabling operation for at least 72 h without a significant decrease of conversion.

Various Perspectives on Microbial Lipase Production Using Agri-Food Waste and Renewable Products

“…Transesterification is categorized into four subclasses according to the chemical species in which the organic group of an ester is replaced by an alcohol, acid or ester. Alcoholysis is the reaction between an ester and an alcohol (Figure 3c) [26], while acidolysis is the reaction between an ester and an acid (Figure 3d) [27]. Interesterification is the reaction between two different esters, where the alcohol and acid moiety is swapped (Figure 3e) [28].…”

Rhizopus oryzae Lipase, a Promising Industrial Enzyme: Biochemical Characteristics, Production and Biocatalytic Applications

“…However, they are found in the environment in low concentrations making the extraction a costly process and not viable to fulfil their growing demand. Therefore, chemical and enzymatic synthesis procedures have arisen to solve flavour esters scarcity [280,281]. Noticeably, the latter exhibits a significant advantage-notwithstanding the already explained benefits of enzymatic synthesis over chemical one in the previous sections-which is the capacity to label the obtained products as natural according to European Legislation (EC 1334/2008) if and when the employed reactants are also natural.…”

“…Thereby, the use of enzymes satisfies consumers trend towards natural products and boosts economic value of the obtained flavour esters [278]. In fact, as well as ROL, other lipases have been used for flavour esters production, for instance, the commercial Novozym ® 435 (Candida antartica lipase B) [280,281], Candida rugosa lipase [282,283] and Burkholderia cepacia lipase [284].…”

“…This way, a final conversion of (S)-benzoin close to the 100% and 96% ee was achieved. Covalently immobilised proROL onto Lewatit-aldehyde support has been reported as an adequate biocatalyst for asymmetric hydrolysis of dimethyl 3-phenylglutarate [280]. Under the best conditions, it was possible to obtain the (R)-methyl-3-phenylglutarate with a 92% ee and an yield in monoester of 97%.…”

Biocatalytic Process Optimization

“…Moreover, 3,4-dimethoxycinnamoylated lysophosphatidylcholine and 3,4-dimethoxycinnamoylated phosphatidylcholine were obtained in isolated yields of 27.5% and 3.5% (w/w), respectively. Huang et al [25] developed a biocatalytic process for synthesizing rose-flavored ester-2-phenylethyl acetate using a packed-bed bioreactor system. The synthesis process was performed in a solvent free system, which is an environmentally friendly process.…”