Metabolome Exploration by High-Resolution Mass Spectrometry Methodologies of Two New Yeast Species: Starmerella reginensis and Starmerella kourouensis

Abstract

Nature is harnessed since ancient times to fulfill human needs, and yeast culture has been mastered for bakery, brewery, or the preparation of beverages. In this context, the two recently discovered yeast species Starmerella reginensis and Starmerella kourouensis, belonging to a genus related to fermentative activities in the literature, were explored via untargeted metabolomics approaches. Ultrahigh-performance liquid chromatography hyphenated with tandem mass spectrometry and a deep investigation of molecular networks and spectral data allowed the annotation of, respectively, 439 and 513 metabolites for S. reginensis and S. kourouensis, with approximatively 30% compound annotations and 40% chemical class annotations for both yeast strains. These analyses and Fourier transform ion cyclotron resonance mass spectrometry accurate metabolic profiles unveiled a rich content of alkaloids, lipids, amino acids, and terpenoids for S. reginensis. S. kourouensis presents a similar profile with more sulfated compounds. In short, these results enrich the current knowledge about Starmerella yeast secondary metabolites and reveal their significant structural diversity of small molecules.

Preparing Biosurfactant Glucolipids from Crude Sophorolipids via Chemical Modifications and Their Potential Application in the Food Industry

“…1−3 Among biosurfactants, sophorolipids (SLs) are considered the most promising class owing to their high fermentation efficiency (extremely high titer of over 400 g/L) and commercial availability. 4 Nevertheless, like other biosurfactants, SLs' high costs render their competitiveness against chemically synthesized surfactants a difficult battle (16− 38 USD/kg vs 1−4 USD/kg), 5,6 especially in the traditional application field of surfactants. Hence, developing high-valueadded applications conducive to the real application of SLs, e.g., in the biomedical sector, is desirable.…”

“…Biosurfactants are ecological renewable alternatives to chemically synthesized surfactants due to their excellent surface/interfacial activities and biocompatibility, and they can be used in extensive fields like in the food, cosmetic, pharmaceutical, and environmental industries. − Among biosurfactants, sophorolipids (SLs) are considered the most promising class owing to their high fermentation efficiency (extremely high titer of over 400 g/L) and commercial availability . Nevertheless, like other biosurfactants, SLs’ high costs render their competitiveness against chemically synthesized surfactants a difficult battle (16–38 USD/kg vs 1–4 USD/kg), , especially in the traditional application field of surfactants.…”

“…In recent years, several studies have focused on the biological activities of SLs, including anticancer, antimicrobial, dermatological, immunoregulatory, spermicidal, and antiviral activities . Sophorolipids are bolaform glycolipid-type biosurfactants synthesized by non-pathogenic yeasts (like Starmerella bombicola ) using sugar and/or vegetable oils as a carbon source . Natural sophorolipids contain a complex mixture of compounds with varying degrees of acetylation and lactonization, the extent of unsaturation of fatty acid chains, and the position of hydroxylation .…”

“…8 Sophorolipids are bolaform glycolipid-type biosurfactants synthesized by non-pathogenic yeasts (like Starmerella bombicola) using sugar and/or vegetable oils as a carbon source. 4 Natural sophorolipids contain a complex mixture of compounds with varying degrees of acetylation and lactonization, the extent of unsaturation of fatty acid chains, and the position of hydroxylation. 9 These variabilities give rise to up to more than 100 types of SL derivatives with assorted physicochemical properties and biological activities.…”