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, k, and catalytic efficiency of recombinant PaAPase were 50 °C, 5.0, 93 mM, 4.2 s, and 2.7 mM min, 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 Ca, pH 4.0, 30 °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.

BACKGROUND: Agmatine is a valuable pharmaceutical intermediate biosynthesised from L-arginine by arginine decarboxylase (EC 4.1.1.19). It has various potential therapeutic functions in neurotransmitter systems, nitric oxide synthesis, and polyamine metabolism. To establish a green and efficient process for agmatine production, a novel arginine decarboxylase (SpA9) from Shewanella putrefaciens was identified, overexpressed, and functionally characterised in this study. RESULTS:The SpA9 gene from S. putrefaciens was overexpressed in Escherichia coli BL21(DE3), and the recombinant SpA9 was purified 7.7-fold. The recombinant SpA9 exhibited a higher K cat /K m value (4.8 s −1 mM −1 ). Furthermore, SpA9 showed the highest activity at pH 8.5 and 37 ∘ C towards L-arginine. The highest enzyme activity of 1281 U mL −1 was achieved by optimising the nutrient, culture, and induction conditions. Under optimum transformation conditions, the maximum conversion yield of agmatine was 92.6%, with a space-time yield of 276.88 g L −1 ·day −1 at a 1 L scale. CONCLUSIONS: To our best knowledge, this bioprocess produced the highest yield and conversion rate of any biocatalyst method reported yet. It is also a greener and more cost-effective method for agmatine production compared with other available methods in the pharmaceutical industry.