To improve 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) production using ultrasonic radiation (UR) treatment.
The production of AA-2G using UR or ultrasonic radiation with shaking (URS) at 150 rpm, at varying power (100 − 500 W), temperature (30 – 65 °C), pH 4.0 −9.0, and time (2−24 h) was compared with that produced in a shaker water bath (SWB) in a reaction catalyzed by cyclodextrin glucanotransferase (CGTase) from Bacillus
sp. SK13.002. The effect of URS on CGTase activity was also measured.
Maximum AA-2G production using UR at a power of 400 W, temperature of 37 °C, and pH 8.0 for 18 h was 5.69 ± 0.2 g/L, while URS at 500 W/150 rpm and 37 °C for 14 h yielded 7.05 ± 0.21 g/L of AA-2G. URS at 500 W/150 rpm, 55 °C, and pH 8.0 for 6 h yielded 6.6 ± 0.25 g/L of AA-2G. URS at 37 and 55 °C significantly increased CGTase activity. AA-2G yield using UR (400 W) was decreased by 9.7 % compared to that produced by SWB. However, the AA-2G yield using USS (500 W/150 rpm) at 37 and 55 °C increased by 11.9 and 4.8 %, respectively, with a reduction in process time of 41.7 and 75 %, respectively, compared to that previously produced by SWB.
These results indicate that UR combined with shaking improves AA-2G production.