Characterization and optimization of carboxylesterase-catalyzed esterification between capric acid and glycerol for the production of 1-monocaprin in reversed micellar system

• Published in: New biotechnology Vol. 27; no. 1; pp. 46 - 52
• Main Authors: Park, Kyung Min, Kwon, Oh Taek, Ahn, Seon Min, Lee, JaeHwan, Chang, Pahn-Shick
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 28.02.2010
• Subjects: Calotropis - enzymology; Calotropis procera; Carboxylesterase - antagonists & inhibitors; Carboxylesterase - metabolism; Copper - metabolism; Decanoic Acids - chemistry; Decanoic Acids - metabolism; Emulsifying Agents - chemistry; Emulsifying Agents - metabolism; Esterification; Glycerides - chemistry; Glycerides - metabolism; Glycerol - chemistry; Glycerol - metabolism; Iron - metabolism; Micelles; Plant Proteins - antagonists & inhibitors; Plant Proteins - metabolism
• ISSN: 1871-6784; 1876-4347
• DOI: 10.1016/j.nbt.2009.11.004

Calotropis procera R. Br. carboxylesterase (EC 3.1.1.1) solubilized in reversed micellar glycerol droplets containing a very small amount of water (less than 5 ppm) and stabilized by a surfactant effectively catalyzed the esterification between glycerol and capric acid to produce 1-monocaprin. Reaction variables including surfactant types, organic solvent media, reaction time, G-value ([glycerol]/[capric acid]), R-value ([water]/[surfactant]), pH, temperature, and types of metal ion inhibitors on the carboxylesterase-catalyzed esterification were characterized and optimized to efficiently produce 1-monocaprin. Bis(2-ethylhexyl) sodium sulfosuccinate (AOT) and isooctane were the most effective surfactant and organic solvent medium, respectively, for 1-monocaprin formation in reversed micelles. The optimum G- and R-values were 3.0 and 0.05, respectively, and the optimum pH and temperature were determined to be 10.0 and 60 °C, respectively. K m,app. and V max,app. were calculated from a Hanes–Woolf plot, and the values were 9.64 mM and 2.45 μM/min mg protein, respectively. Among various metal ions, Cu 2+ and Fe 2+ severely inhibited carboxylesterase-catalyzed esterification activity (less than 6.0% of relative activity).