Enhancement of the thermal and alkaline pH stability of Escherichia coli lysine decarboxylase for efficient cadaverine production.

OBJECTIVE

To enhance the thermal and alkaline pH stability of the lysine decarboxylase from Escherichia coli (CadA) by engineering the decameric interface and explore its potential for industrial applications.

RESULTS

The mutant T88S was designed for improved structural stability by computational analysis. The optimal pH and temperature of T88S were 7.0 and 55 °C (5.5 and 50 °C for wild-type). T88S showed higher thermostability with a 2.9-fold increase in the half-life at 70 °C (from 11 to 32 min) and increased melting temperature (from 76 to 78 °C). Additionally, the specific activity and pH stability (residual activity after 10 h incubation) of T88S at pH 8.0 were increased to 164 U/mg and 78% (58 U/mg and 57% for wild-type). The productivity of cadaverine with T88S (284 g L-lysine L and 5 g DCW L) was 40 g L h, in contrast to 28 g L h with wild-type.

CONCLUSION

The mutant T88S showed high thermostability, pH stability, and activity at alkaline pH, indicating that this mutant is a promising biocatalyst for industrial production of cadaverine.