Identification of the gene responsible for the synthesis of volatile sulfur compounds in Brevibacterium linens

Abstract

The enzymatic degradation of L-methionine and subsequent formation of volatile sulfur compounds (VSC) is believed to be essential for flavour development in cheese. L-methionine γ-lyase (MGL) can convert L-methionine to methanethiol (MTL) α-ketobutyrate and ammonia. The MGL gene encoding MGL was cloned from the type strain Brevibacterium linens ATCC 9175 known to produce copious amounts of MTL and related VSC. The disruption of the MGL gene, achieved in strain ATCC 9175, resulted in a 97% decrease in total VSC production in the knockout strain. Our work shows that L-methionine degradation via γ-elimination is a key step to form VSC in B. linenes.