# Screening and mutagenesis breeding of B. A salt YB13 for high producing tetramethylpyrazine and the application of its fortified Daqu for improving the quality of mixed-flavor baijiu

## TL;DR

Researchers improved a microbe to produce more tetramethylpyrazine, which enhanced the flavor and quality of a type of Chinese白酒 (baijiu).

## Contribution

A high-yield tetramethylpyrazine-producing strain was developed and shown to improve baijiu quality through microbial enhancement.

## Key findings

- B. halotolerans YB13 was enhanced to produce 2.98 g/kg of tetramethylpyrazine.
- Fortified Daqu improved microbial diversity and flavor compound levels in baijiu.
- Acid protease and starch were key factors in flavor formation, with higher sensory scores in the experimental group.

## Abstract

This study isolated B. halotolerans YB13 from high-temperature Daqu and enhanced its tetramethylpyrazine (TTMP) yield to 2.98 g/kg through screening and plasma mutagenesis. The fortified Daqu containing YB13 was used in Mixed-flavor Baijiu fermentation. Compared to the control, the experimental group showed higher microbial diversity and more flavor compounds. Starch and acid protease were key physicochemical factors affecting flavor formation, with acid protease positively correlating with major flavors like ethyl palmitate, acetic acid, and octanoic acid. Dominant microbes (Lactobacillus, Thermoascus, Aspergillus) in the experimental group were strongly correlated with esters, acids, and alcohols. TTMP content and sensory scores were significantly higher in the experimental group, demonstrating the potential of microbial enhancement to improve baijiu quality.

•A high-TTMP-producing B. halotolerans YB13 was obtained by screening and mutagenesis.•Fortified Daqu of B. halotolerans YB13 enhances the quality of complex-flavor Baijiu.•Dynamic difference of Jiupei microbiota and flavor by the fortified Daqu was revealed.•Flavor correlations decode fortified Daqu's Baijiu quality enhancement mechanism.

A high-TTMP-producing B. halotolerans YB13 was obtained by screening and mutagenesis.

Fortified Daqu of B. halotolerans YB13 enhances the quality of complex-flavor Baijiu.

Dynamic difference of Jiupei microbiota and flavor by the fortified Daqu was revealed.

Flavor correlations decode fortified Daqu's Baijiu quality enhancement mechanism.