Combinatorial approach for improved production of whole-cell 3-aminopropionic acid in recombinant : codon optimization, gene duplication and process optimization.

Unlabelled: In this study, we aimed to develop a based whole-cell biocatalyst for the bio-production of 3-aminopropionic acid (3-APA). l-aspartate-α-decarboxylases (ADC) (EC: 4.1.1.11) from , , , and  were expressed in . derived ADC ( ) exhibited the highest ADC activity of 0.9 ± 0.02 U/mL in recombinant . Combination of codon optimization and gene duplication strategies resulted in 415.56% enhancement of ADC activity compared to . The culture growth conditions of (BMD-7) for 3-APA production were optimized as follows: inducer concentration, 0.5% (w/v); time of induction, 3 h; induction temperature, 37 °C and post-induction incubation time, 8 h. Improvement of the whole-cell biocatalytic process efficiency, was dealt by optimization of reaction temperature, reaction pH, metal ion additives and l-aspartic acid concentration. Shake flask level experiments yielded an enhanced 3-APA titer (16.18 ± 0.26 g/L) and a yield of 0.89 g/g under optimized conditions viz., 45 °C, pH 6.0 and 20 g/L of l-aspartic acid. This study demonstrates the potential of for 3-APA production and paves the scope for the development of 3-APA producing strains in near future.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-021-02885-7.