Cell factory for γ-aminobutyric acid (GABA) production using Bifidobacterium adolescentis

Abstract

Background Bifidobacteria are gram-positive, probiotic, and generally regarded as safe bacteria. Techniques such as transformation, gene knockout, and heterologous gene expression have been established for Bifidobacterium, indicating that this bacterium can be used as a cell factory platform. However, there are limited previous reports in this field, likely because of factors such as the highly anaerobic nature of this bacterium. Bifidobacterium adolescentis is among the most oxygen-sensitive Bifidobacterium species. It shows strain-specific gamma-aminobutyric acid (GABA) production. GABA is a potent bioactive compound with numerous physiological and psychological functions. In this study, we investigated whether B. adolesentis could be used for mass production of GABA. Results The B. adolescentis 4–2 strain isolated from a healthy adult human produced approximately 14 mM GABA. It carried gadB and gadC, which encode glutamate decarboxylase and glutamate GABA antiporter, respectively. We constructed pKKT427::Pori-gadBC and pKKT427::Pgap-gadBC plasmids carrying gadBC driven by the original gadB (ori) and gap promoters, respectively. Recombinants of Bifidobacterium were then constructed. Two recombinants with high production abilities, monitored by two different promoters, were investigated. GABA production was improved by adjusting the fermentation parameters, including the substrate concentration, initial culture pH, and co-factor supplementation, using response surface methodology. The optimum initial cultivation pH varied when the promoter region was changed. The ori promoter was induced under acidic conditions (pH 5.2:4.4), whereas the constitutive gap promoter showed enhanced GABA production at pH 6.0. Fed-batch fermentation was used to validate the optimum fermentation parameters, in which approximately 415 mM GABA was produced. The conversion ratio of glutamate to GABA was 92–100%. Conclusion We report high GABA production in recombinant B. adolescentis. This study provides a foundation for using Bifidobacterium as a cell factory platform for industrial production of GABA.

Prenatal Lead Exposure Is Associated with Reduced Abundance of Beneficial Gut Microbial Cliques in Late Childhood: An Investigation Using Microbial Co-Occurrence Analysis (MiCA)

“…R. callidus is a short-chain fatty-acid-producing bacteria with anti-inflammatory function. − Low abundance of R. callidus has been associated with Parkinson’s disease, colitis and Crohn’s disease, ,, liver disease, and obesity − B. adolescentis is commonly used as a probiotic supplement and has been linked to the prevention and alleviation of many detrimental health conditions, including liver disease, , colitis, , viral infection, , arthritis, type 2 diabetes, anxiety, depression, and other mental health disorders. , Additionally, B. adolescentis is known to modify the overall composition of the gut microbiome, perhaps its most relevant feature for this analysis, increasing the abundance of other probiotic or beneficial bacteria within the microbiome and amplifying its beneficial effects. − Thus, our finding of B. adolescentis as a member of both the 2-taxa and 3-taxa microbial clique, in combination with other potentially beneficial bacterial taxa, is highly consistent with previous literature. − When considering the findings of our analysis in the context of this previous evidence, it is clear that prenatal Pb exposure, particularly in the second trimester of pregnancy, has the potential to lead to several detrimental health outcomes via alterations in the gut microbiome, specifically by reducing the abundance of these 2-taxa and 3-taxa microbial cliques.…”

Serum metabolomics analysis in patients with alcohol dependence

“…These findings indicated that alcohol consumption might be responsible for the altered plasma glutamate and glutamine levels. GABA, an inhibitory neurotransmitter in the central nervous system, is synthesized from glutamate through a process catalyzed by decarboxylase ( 36 ). In the current study, we found significant upregulation of the serum levels of GABA and 4-hydroxybutanoic acid.…”

Recombinant Probiotic Preparations: Current State, Development and Application Prospects

“…paracasei [196]. The possibility of creating E. coli Nissle 1917 probiotic strain with the ability to biosynthesize omega-3 fatty acids, particularly eicosapentaenoic and docosahexaenoic, is being investigated as well [197].…”