Central Composite Design Optimization for the Synthesis of Butyl Acetate Catalyzed by Liquid Lipase

Butyl acetate, a valuable flavor ester, is conventionally synthesized through acid-catalyzed reactions, which suffer from environmental concerns and inefficiencies. This study explores a greener alternative using liquid lipase Novozym 400238 for its enzymatic synthesis. The central composite design (CCD) within response surface methodology (RSM) was employed to assess the reaction parameters, including temperature, substrate molar ratio, enzyme concentration, and hexane content, along with their effects on the conversion rate. Following model optimization, the optimal reaction conditions were identified as follows: a temperature of 45°C, a molar ratio of n-butanol to acetate ion of 4:1, an enzyme concentration of 8.3%, and a hexane content of 60%. Under these conditions, the esterification reaction lasted for 5 h and achieved a yield exceeding 90%. Furthermore, the liquid lipase exhibited high reusability, maintaining over 80% yield for 11 cycles under optimal conditions. These findings showcase the potential of liquid lipase as a cost-effective and sustainable catalyst for butyl acetate synthesis, offering a promising avenue for green and eco-friendly production processes.