Characterization of arginine utilization strains from fermented grains and evaluation of their contribution to citrulline accumulation in Chinese Luzhou-flavor spirits

Abstract

Objective: This study aimed to characterize microorganisms responsible for accumulation of ethyl carbamate precursor citrulline in fermented grains during Luzhou-flavor spirits fermentation process, to provide theoretical basis for clarifying mechanisms of ethyl carbamate formation.

Methods: High-throughput strain screening approach was used to isolate strains with high arginine utilization and high citrulline accumulation capability. Essential genes that comprise the arginine deiminase pathway of these isolates were verified and a modified Chinese liquor fermentation process was conducted by adding these strains.

Results: A total of 20 strains with high arginine utilizing ability were obtained. Among them, Lactococcus garvieae LD3, Bacillus amyloliquefaciens BG5, Pediococcus acidilactici PH7 and Staphylococcus pasteuri SH11 exhibited high efficacy to produce citrulline from arginine. These strains could also increase citrulline in fermented grains.

Conclusion: The accumulation of citrulline in fermented grains was confirmed to be corresponding to arginine utilization by Lactococcus garvieae, Bacillus amyloliquefaciens, Pediococcus acidilactici and Staphylococcus pasteuri through the arginine deiminase pathway.