Efficient Production of (R)-3-Aminobutyric Acid by Biotransformation of Recombinant E. coli

(R)-3-aminobutyric acid is an important raw material for dolutegravir production, which is a key antiretroviral medicine for AIDS treatment. Currently, the industrial production of (R)-3-aminobutyric acid relies on chiral resolution methods, which are plagued by high pollution and low yield efficiency. Here, we report an efficient pathway for (R)-3-aminobutyric acid production via engineered aspartase-driven biotransformation in recombinant E. coli. The engineered aspartase mutants, obtained through rational design based on catalytic mechanisms, were specifically employed to catalyze the production of (R)-3-aminobutyric acid from crotonic acid. The engineered T187L/N142R/N326L aspartase mutant exhibited the highest enzyme activity of 1516 U/mg. Through cell permeabilization, the system achieved (R)-3-aminobutyric acid yield of 287.6 g/L (96% productivity) within 24 h. Subsequent scale-up in a 7 L fermenter achieved a final product yield of 284 g/L (95% productivity) within 24 h. Economic balance showed that the cost of industrial production (¥116.21/kg) is about 1/4 of the laboratory production (¥479.76/kg). In summary, the engineered aspartase-mediated bioconversion pathway using recombinant E. coli offers an industrially viable approach for (R)-3-aminobutyric acid production, featuring mild reaction conditions, environmental sustainability, streamlined processing, high yield, and cost-effective substrates.