Continuous production of acyl L-ascorbates using a packed-bed reactor with immobilized lipase

Saturated acyl (6-O-caproyl, lauroyl, and myristoyl) and unsaturated acyl (6-O-oleoyl, linoleoyl, and arachidonoyl) L-ascorbates were continuously synthesized at 50degreesC using a system where a column packed with ascorbic acid powder and a packed-bed reactor with an immobilized lipase from Candida antarctica were connected in series. A productivity of 1.6-1.9 kg/L reactor-cl was achieved for at least 11 d. The surface tension of the caproyl or lauroyl L-ascorbate in aqueous solution was measured at various temperatures and pH to estimate the critical micelle concentration (CMC) of the acyl L-ascorbate. The CMC values were independent of temperature but dependent on the pH. The value of the caproyl ascorbate increased with an increase in pH.