Exploring Carbon-Sulfur (CS) Lyase Enzymes across Microbial Diversity for Enhanced Thiol Release in Beer and Wine

Different precursors of volatile sulfur compounds (VSCs) are present in fermented beverages, such as wine and beer. Carbon-sulfur (CS) lyases are enzymes that play a crucial role in releasing aromas from these varietal thiol precursors. These enzymes are expressed by various organisms, including yeasts and bacteria, involved in fermentation processes during brewing and winemaking. However, only a small fraction of these precursors is metabolized into volatile sulfur compounds. One approach to enhance aroma release involves adding exogenous CS lyases at a specific stage of fermentation. In this study, we selected and recombinantly produced three wild-type CS lyases and two mutated variants and investigated their ability to convert thiol precursors in vitro under various conditions, including different pH levels and the presence of amino acids, which might interfere with enzyme activity. Finally, we evaluated the potential effect of adding exogenous purified CS lyases during pilot-scale brewing (ale and lager) and winemaking (Sauvignon Blanc). However, no significant increase in volatile sulfur compound levels was observed. We discuss our findings in the context of the future application and optimization of this strategy in real winemaking and brewing.