Clavispora mexcalensis sp. nov.: a novel Mexican yeast species isolated from mezcal must with promising polyol and ethanol production from lignocellulose hydrolysates

Yeasts are micro-organisms with high biotechnological potential for various industrial processes. Non-conventional yeasts offer advantages over classic Saccharomyces yeasts, such as the ability to assimilate pentoses natively. This project aimed to describe and characterize a new yeast species isolated from mezcal must in Oaxaca, México. For its identification, whole-genome sequencing was performed. Phylogenomic analyses (BUSCO, OrthoFinder and IQ-TREE) indicated 99.0% genome completeness of included 2,319 orthologs. Comparative genomic analyses were performed using average nucleotide identity (ANI), calculated with FastANI and core-proteome phylogenomics, complemented by average amino acid identity (AAI) comparisons. Additionally, macro- and micro-morphological analyses (the latter by scanning electron microscopy) were performed. l -arabinose assimilation and thermotolerance were also assessed. The uptake of various sugars, including xylose and arabinose, was evaluated, and the corresponding metabolic pathways were confirmed through experimental and genomic analyses. Phylogenomic analysis, together with FastANI and complementary AAI values, confirmed that, despite its close relationship to Clavispora lusitaniae and Clavispora paralusitaniae , this strain represents a novel species, for which the name Clavispora mexcalensis sp. nov. is proposed. The strain exhibits marked thermotolerance, maintaining substantial growth at 48 °C. It assimilates glucose, d -xylose, l -arabinose and cellobiose as sole carbon sources, and produces xylitol, ethanol and arabitol. Macro- and micro-morphological characteristics are consistent with those of other members of the genus Clavispora , although some cells exhibit numerous bud scars. These results expand the known diversity of yeasts associated with mezcal and indicate that Cl. mexcalensis sp. nov. is a potential candidate for biotechnological applications requiring high-temperature tolerance or the bioconversion of unconventional sugars.