Harnessing dual applications of a novel ascomycetes yeast, sp. nov., as a biocatalyst for stereoselective ketone reduction and biosurfactant production.

New bioresources for catalytic application and fine chemical synthesis are the need of the hour. In an effort to find out new biocatalyst for oxidation-reduction reaction, leading to the synthesis of chiral intermediates, novel yeast were isolated from unique niche and employed for the synthesis of value added compounds. To determine the genetic relatedness of the isolated strain, HSB-15, sequence analysis of the internal transcribed spacer (ITS) and D1/D2 domains of the 26S rRNA gene sequence was carried out. The distinctive features of the strain HSB-15 were also identified by phenotypic characterization. The isolated strain HSB-15 was employed for the reduction of selected naphthyl ketones to their corresponding alcohols and a biosurfactant was isolated from its culture broth. The analysis of the ITS and D1/D2 domains of the 26S rRNA gene revealed that strain HSB-15 is closely related to the type strain of (CBS 15147) with 96.3% and 97.7% sequence similarity, respectively. However, concatenated sequences of the ITS gene and D1/D2 domain showed 94.6% sequence similarity. Phenotypic characterization indicated significant differences between strain HSB-15 and its closely related species and consequently, it was identified as a novel species, leading to the proposal of the name sp. nov. The strain was able to reduce selected naphthyl ketones to their corresponding alcohols with remarkable efficiency, within a 12-hours. The strain HSB-15T also produced a surfactant in its culture broth, identified as sophorolipid upon analysis. The study explored the potential of the novel strain, HSB-15T, as a whole-cell biocatalyst for the reduction of naphthyl ketones to their corresponding alcohols and also reports its capability to produce sophorolipid, a biosurfactant, in its culture broth. This dual functionality of HSB-15T both as biocatalyst and biosurfactant producer enhances its applicability in biotechnology and environmental science.