Enzymatic Production of Ascorbic Acid-2-phosphate by Recombinant Acid Phosphatase

In this study, an environmentally friendly and efficient enzymatic method for the synthesis of L-ascorbic acid-2-phosphate (AsA-2P) from L-ascorbic acid (AsA) was developed. The Pseudomonas aeruginosa acid phosphatase (PaAPase) was expressed in Escherichia coli BL21. The optimal temperature, optimal pH, K-m, k(cat), and catalytic efficiency of recombinant PaAPase were 50 degrees C, 5.0, 93 mM, 4.2, s(-1), and 2.7 mM(-1) min(-1), respectively. The maximal dry cell weight and PaAPase phosphorylating activity reached 8.5 g/L and 1127.7 U/L, respectively. The highest AsA-2P concentration (50.0 g/L) and the maximal conversion (39.2%) were obtained by incubating 75 g/L intact cells with 88 g/L AsA and 160 g/L sodium pyrophosphate under optimal conditions (0.1 mM Ca2+, pH 4.0, 30 degrees C) for 10 h; the average AsA-2P production rate was 5.0 g/ L/h, and the AsA-2P production system was successfully scaled up to a 7.5 L fermenter. Therefore, the enzymatic process showed great potential for production of AsA-2P in industry.