Migration of glutamate decarboxylase by cold treatment on whole-cell biocatalyst triggered activity for 4-aminobutyric acid production in engineering Escherichia coli.
Int J Biol Macromol
; 190: 113-119, 2021 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-34480902
ABSTRACT
Glutamate decarboxylase B (GadB) from Escherichia coli, an intrinsic pyridoxal 5'-phosphate (PLP)-dependent enzyme has been employed for 4-aminobutyric acid (GABA) biosynthesis, which involves the glutamate import and GABA export via a transporter located in the inner membrane as rate determined step of whole-cell (WC) biotransformation. Herein, GadB was cloned and overexpressed in E. coli under a constitutive promoter in a high copy number plasmid, and 46.9 g/L GABA was produced. It was observed that GadB migrated to the periplasm when the WC were subjected to -20 °C cold treatment for 24 h prior to the biotransformation. Kinetic studies indicated that the enzymatic turnover rate of WC increased 2-fold after cold treatment, which was correlated with the migration rate of GadB, and up to 88.6% of GadB. The export or possible migration of GadB mitigated the rate-limiting step of WC biotransformation, and a 100% conversion of substrate to GABA was obtained. Finally, we launched a promising strategy for GABA production of 850 g/L from cost-effective monosodium glutamate (MSG) by using WC biocatalysts with 10-times recycling.
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Base de dados:
MEDLINE
Assunto principal:
Engenharia Genética
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Temperatura Baixa
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Escherichia coli
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Biocatálise
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Ácido gama-Aminobutírico
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Glutamato Descarboxilase
Idioma:
En
Revista:
Int J Biol Macromol
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Taiwan