Effect of shaking velocity on mono-glycosyl-stevioside productivity via alternansucrase acceptor reaction

• Using shaking velocity to maximize mono-glycosyl-stevioside productivity via alternansucrase acceptor reaction and minimize the reaction time.
• Macroporous resin AB-8 exhibited high separation efficiency of steviol glucosyl.
• Mono-glucosylated stevioside by Leuconostoc citreum SK24.002 alternansucrase acceptor reaction was successfully isolated.
• Structural characterization of the mono-glucosylated product of stevioside was assigned.

In this study, effect of shaking velocity on mono-glycosyl-stevioside production by Leuconostoc citreum SK24.002 alternansucrase acceptor reaction was investigated, with four different level of shaking velocity (75, 100, 125 and 150 rpm) up to 24 h at 25 °C, using sucrose as donor and stevioside as acceptor. The results revealed that mono-glycosyl-stevioside yield significantly increased with increase in the reaction shaking velocity and reached maximum yield of 3.78 ± .02 mg/mL at 150 rpm shaking velocity after 6 h of reaction. And an increase in the reaction shaking velocity up to 150 rpm reduced the final reaction time and increased the productivity of mono-glycosyl-stevioside product such that the high quantity of mono-glycosyl-stevioside product was produced in only 6 h rather than 24 h. The mono-glycosyl-stevioside product was completely separated using macroporous resin AB-8 flowed by semi-preparative HPLC. Macroporous resin AB-8 showed high selectivity and capacity toward mono-glycosyl-stevioside. The structure of mono-glycosyl-stevioside was characterized, as 13-{[α-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl]oxy}kaur-16-en-19-oic acid β-d-glucopyranosyl eater, a corroding to extensive 1D and 2D NMR (1H and 13C, COSY, HSQC, HMBC) and mass spectral data.

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