[Biocatalytic access to β-alanine by a two-enzyme cascade synthesis]

Enzymatic synthesis is an important way to produce β-alanine, but the biological method is expensive generally because of the high price of substrate. In this paper, a two-step enzymatic cascade system was developed, combining L-aspartase from Escherichia coli DH5α and L-aspartate α-decarboxylase from Corynebacterium glutamicum. This system catalyzes Fumarate and ammonia to β-alanine. The optimal ratio of AspA and PanD was 1:80 (W/W), and the concentration of AspA was 10 μg/mL, at 37 ℃ and pH 7.0. When the concentration of Fumarate was 100 mmol/L, the reaction reached its equilibrium after 8 h, and the yield of β-alanine was 90 mmol/L (7 g/L). The yield of β-alanine can reach 126 mmol/L (9.8 g/L) when the concentration of Fumarate increased to 200 mmol/L. Extending reaction time, the conversion rate did not change obviously. Using this two-step enzymatic cascade system, β-alanine from cheaper substrate Fumarate can be obtained.