posted on 2024-02-09, 17:33authored byYajing Li, Qi Chen, Siyao Liu, Lin Deng, Shichao Li, Renjun Gao
The limited availability of high-cost
nucleotide sugars is a significant
constraint on the application of their downstream products (glycosides
and prebiotics) in the food or pharmaceutical industry. To better
solve the problem, this study presented a one-pot approach for the
biosynthesis of UDP-Gal using a thermophilic multienzyme system consisting
of GalK, UGPase, and PPase. Under optimal conditions, a 2 h reaction
resulted in a UTP conversion rate of 87.4%. In a fed-batch reaction
with Gal/ATP = 20 mM:10 mM, UDP-Gal accumulated to 33.76 mM with a
space-time yield (STY) of 6.36 g/L·h–1 after the second feeding. In repetitive batch synthesis, the average
yield of UDP-Gal over 8 cycles reached 10.80 g/L with a very low biocatalyst
loading of 0.002 genzymes/gproduct. Interestingly,
Galk (Tth0595) could synthesize Gal-1P using ADP as a donor of phosphate
groups, which had never been reported before. This approach possessed
the benefits of high synthesis efficiency, low cost, and superior
reaction system stability, and it provided new insights into the rapid
one-pot synthesis of UDP-Gal and high-value glycosidic compounds.