Abstract:
2-O-α-D-Glucopyranosyl-L-ascorbic acid (AA-2G) is an important
industrial derivative of L-ascorbic acid (AA), which has the distinct
advantages of non-reducibility, antioxidation, and reproducible
decomposition into L-ascorbic acid and glucose. Enzymatic synthesis is a
preferred method for AA-2G production over alternative chemical
synthesis owing to the regioselective glycosylation reaction.α -Glucosidase, an enzyme classed into O - glycoside
hydrolases, may be used in glycosylation reactions to synthesize AA-2G.
Here, one α-glucosidase from Oryza sativa (rAGL) was
recombinantly produced in Pichia pastoris GS115 and used for
biosynthesis of AA-2G with few intermediates and byproducts. The
extracellular rAGL reached 9.11 U/mL after fed-batch cultivation for 102
h in a 5-L fermenter. The specific activity of purified rAGL is 49.83
U/mg at 37 °C and pH 4.0. The optimal temperature of rAGL was 65 °C, and
it was stable below 55 °C. rAGL was active over the range of pH
3.0–7.0, with the maximal activity at pH 4.0. Under the condition of 37
°C , pH 4.0, equimolar maltose and AA·Na, 8.7±0.4 g/L of AA-2G was
synthesized by rAGL. These studies lay the basis for the industrial
application of recombinant α -glucosidase.
Keywords: α -Glucosidase; Oryza sativa ;
2-O-α -D-glucopyranosyl-L-ascorbic acid; Transglycosylation;