Abstract: Low catalytic ability and poor stability limit industrial applications of L-aspartate α-decarboxylase. This study was therefore conducted to improve the catalytic activity of L-aspartate α-decarboxylase to promote biological production of β-alanine in industries. Based on evolutionary information of thermophilic bacteria, L-aspartate α-decarboxylase from Tribolium castaneum was molecularly modified to improve its enzyme stability. The mutant strain K221R was screened, as it had improved thermal stability and enzymatic activity. Compared with the wild type, the specific enzyme activity of K221R increased 20.3%. Moreover, after incubating the enzyme at 50 ℃ for 30 min, the residual activity of the wild type was 0, while K221R remained 43% activity. Furthermore, up to 134.72 g/L β-alanine was produced using K221R-expression whole cells, which was the highest production level achieved up-to-date, with 94.52% molar conversion rate. In conclusion, the engineered strain containing K221 variant has great potential for industrial production of β-alanine.
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