Biomaterial Database

Enhancement of γ-aminobutyric acid production in recombinant Corynebacterium glutamicum by co-expressing two glutamate decarboxylase genes from Lactobacillus brevis. 2013

Feng Shi, and Junjun Jiang, and Yongfu Li, and Youxin Li, and Yilong Xie

State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China, shifeng@jiangnan.edu.cn.

γ-Aminobutyric acid (GABA), a non-protein amino acid, is a bioactive component in the food, feed and pharmaceutical fields. To establish an effective single-step production system for GABA, a recombinant Corynebacterium glutamicum strain co-expressing two glutamate decarboxylase (GAD) genes (gadB1 and gadB2) derived from Lactobacillus brevis Lb85 was constructed. Compared with the GABA production of the gadB1 or gadB2 single-expressing strains, GABA production by the gadB1-gadB2 co-expressing strain increased more than twofold. By optimising urea supplementation, the total production of L-glutamate and GABA increased from 22.57 ± 1.24 to 30.18 ± 1.33 g L⁻¹, and GABA production increased from 4.02 ± 0.95 to 18.66 ± 2.11 g L⁻¹ after 84-h cultivation. Under optimal urea supplementation, L-glutamate continued to be consumed, GABA continued to accumulate after 36 h of fermentation, and the pH level fluctuated. GABA production increased to a maximum level of 27.13 ± 0.54 g L⁻¹ after 120-h flask cultivation and 26.32 g L⁻¹ after 60-h fed-batch fermentation. The conversion ratio of L-glutamate to GABA reached 0.60-0.74 mol mol⁻¹. By co-expressing gadB1 and gadB2 and optimising the urea addition method, C. glutamicum was genetically improved for de novo biosynthesis of GABA from its own accumulated L-glutamate.

UI	MeSH Term	Description	Entries
D005285	Fermentation	Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.	Fermentations
D005680	gamma-Aminobutyric Acid	The most common inhibitory neurotransmitter in the central nervous system.	4-Aminobutyric Acid,GABA,4-Aminobutanoic Acid,Aminalon,Aminalone,Gammalon,Lithium GABA,gamma-Aminobutyric Acid, Calcium Salt (2:1),gamma-Aminobutyric Acid, Hydrochloride,gamma-Aminobutyric Acid, Monolithium Salt,gamma-Aminobutyric Acid, Monosodium Salt,gamma-Aminobutyric Acid, Zinc Salt (2:1),4 Aminobutanoic Acid,4 Aminobutyric Acid,Acid, Hydrochloride gamma-Aminobutyric,GABA, Lithium,Hydrochloride gamma-Aminobutyric Acid,gamma Aminobutyric Acid,gamma Aminobutyric Acid, Hydrochloride,gamma Aminobutyric Acid, Monolithium Salt,gamma Aminobutyric Acid, Monosodium Salt
D005968	Glutamate Decarboxylase	A pyridoxal-phosphate protein that catalyzes the alpha-decarboxylation of L-glutamic acid to form gamma-aminobutyric acid and carbon dioxide. The enzyme is found in bacteria and in invertebrate and vertebrate nervous systems. It is the rate-limiting enzyme in determining GAMMA-AMINOBUTYRIC ACID levels in normal nervous tissues. The brain enzyme also acts on L-cysteate, L-cysteine sulfinate, and L-aspartate. EC 4.1.1.15.	Glutamate Carboxy-Lyase,Glutamic Acid Decarboxylase,Acid Decarboxylase, Glutamic,Carboxy-Lyase, Glutamate,Decarboxylase, Glutamate,Decarboxylase, Glutamic Acid,Glutamate Carboxy Lyase
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D001426	Bacterial Proteins	Proteins found in any species of bacterium.	Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol
D048230	Corynebacterium glutamicum	A species of gram-positive, asporogenous, non-pathogenic, soil bacteria that produces GLUTAMIC ACID.
D052196	Levilactobacillus brevis	A species of gram-positive, rod-shaped LACTIC ACID bacteria that is frequently used as starter culture in SILAGE fermentation, sourdough, and lactic-acid-fermented types of beer and wine.	Lactobacillus brevis
D061249	Batch Cell Culture Techniques	Methods for cultivation of cells, usually on a large-scale, in a closed system for the purpose of producing cells or cellular products to harvest.	Batch Culture Techniques,Batch Culture,Continuous Batch Culture,Fed Batch Culture Techniques,Fed-Batch Culture,Fed-Batch Culture Techniques,Shake-Flask Culture,Batch Culture Technique,Batch Culture, Continuous,Batch Cultures,Batch Cultures, Continuous,Continuous Batch Cultures,Culture Technique, Batch,Culture Technique, Fed-Batch,Culture Techniques, Batch,Culture Techniques, Fed-Batch,Culture, Batch,Culture, Continuous Batch,Culture, Fed-Batch,Culture, Shake-Flask,Cultures, Batch,Cultures, Continuous Batch,Cultures, Fed-Batch,Cultures, Shake-Flask,Fed Batch Culture,Fed-Batch Culture Technique,Fed-Batch Cultures,Shake Flask Culture,Shake-Flask Cultures,Technique, Batch Culture,Technique, Fed-Batch Culture,Techniques, Batch Culture,Techniques, Fed-Batch Culture