Enhancing lipase-catalyzed production of erythorbyl ricinoleate: A strategy for water removal using adsorbents in a solvent-free bioreactor system

This study aimed to enhance erythorbyl ricinoleate (ERO) production in a solvent-free bioreactor system by removing the water produced during lipase-catalyzed esterification. Reaction conditions were optimized with gas flow rate of 2.0 L/min, substrate molar ratio [(ricinoleic acid):(erythorbic acid)] of 2.0, and temperature at 60 degrees C. The initial water content was controlled between 0.015 g/100 g and 0.055 g/100 g with the highest initial reaction rate (0.020 +/- 0.002 mmol/h) observed at a water content of 0.025 g/100 g. Removal of the water generated during esterification by adsorbents significantly increased the initial reaction rate, but excessive removal of water decreased the reaction rate. The initial reaction rate (0.034 +/- 0.002 mmol/h) achieved by adding 10 mg/mL molecular sieve 4 & Aring; at the beginning of the reaction was 1.65-fold higher than that without adsorbent (0.027 +/- 0.001 mmol/h). These findings provide significant insights for optimizing the immobilized lipase-catalyzed production of organic compounds, particularly in solvent-free bioreactor systems.