Isolation and Identification of Aroma-producing Yeasts and Effects on Aroma Increase of Low Grade Tobacco Leaves

Aroma-producing microorganisms can effectively enhance the quality and aroma of tobacco leaves, which is particularly significant for the reuse of low grade tobacco. This study aimed to explore the possibility of developing characteristic tobacco extract products through microbial aroma-producing fermentation of low grade tobacco leaves. Aroma-producing yeasts were isolated from flue-cured tobacco leaves and Xuan distillery samples, and strains suitable for enhancing tobacco flavor were isolated and identified based on sensory evaluation, morphological observations, and molecular biological identification. The aromatic components in the fermentation broth were analyzed using GC-MS to determine the main aromatic substances and their changes. Subsequently, extract products were added to the cigarettes for sensory evaluation. Ultimately, eight strains of aroma-producing yeast with distinct aroma characteristics were isolated, i.e., Saccharomyces cerevisiae, Millerozyma farinosa, Wickerhamomyces anomalus, Meyerozyma caribbica, Pichia manshurica, Pichia kudriavzevii, Trichosporon asahii and Trichosporon coremiiforme. GC-MS analysis revealed that the selected strains could produce alcohols such as phenylethanol, isobutanol and isoamyl alcohol; esters such as ethyl acetate and isoamyl acetate; as well as various unique aroma components through liquid fermentation of low grade tobacco leaves, resulting in improved aroma quality. Strain CH-5 exhibited superior effect on enhancing aromas and has potential for further optimization and development of extract products.