# Enhanced Postbiotic Metabolite GABA Production in Skim Milk Using Weissella cibaria UF-274 and Whole-Genome Analysis

## TL;DR

This study improves GABA production in skim milk using a lactic acid bacterium and analyzes its genome to confirm its safety and functionality.

## Contribution

The study identifies optimal conditions for GABA production and provides genomic evidence of the bacterium's functionality and safety.

## Key findings

- Optimal GABA production in skim milk occurs with specific concentrations of glucose, monosodium glutamate, and pyridoxal-5′-phosphate.
- Genome analysis reveals a glutamine amidotransferase linked to the GABA pathway and two biosynthetic gene clusters.
- The strain shows no antibiotic resistance genes and low pathogen risk, making it suitable for functional food development.

## Abstract

Background/Objectives: Gamma-aminobutyric acid (GABA) is a bioactive, non-proteinaceous amino acid with potential health benefits. Weissella cibaria UF-274 is an important lactic acid bacterium isolated from Balinese fermented sausage (urutan) with GABA-producing abilities. The aim of this study was to enhance GABA synthesis in skim milk as a basal substrate, as well as whole genome sequencing and analysis to evaluate the functionality and safety of the strain. Methods: A Box–Behnken response surface design was used to enhance GABA accumulation in skim milk. Results: The optimum conditions for GABA production were at concentrations of glucose of 23.91 g/L, monosodium glutamate concentrations of 2.32 g/L and pyridoxal-5′-phosphate at 46 μM. The genome assembly produced a high-quality draft with a 2.53 Mb circular chromosome and 2378 coding sequences. A whole genome analysis revealed that the strain possesses a glutamine amidotransferase (puuD-like) as an alternative route linked to the GABA pathway. AntiSMASH prediction results showed that the strain has two biosynthetic gene clusters including terpene and type III polyketide synthases. Several bioinformatic approaches predicted no antibiotic resistance genes, while van genes encoding vancomycin resistance were detected with low pathogen risk with one approach. Conclusions: Weissella cibaria UF-274 is a promising GABA producer with genomic evidence and a good candidate for functional food development.