AUTHOR=Kumar Sachin , Verma Nitish Kumar , Basotra Sandal Deep , Sharma Divya , Prasad G. S. , Bhattacharyya Mani Shankar 

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

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1264826

DOI=10.3389/fbioe.2023.1264826

ISSN=2296-4185

ABSTRACT=<p><bold>Introduction:</bold> 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.</p><p><bold>Methods:</bold> To determine the genetic relatedness of the isolated strain, HSB-15<sup>T</sup>, 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<sup>T</sup> were also identified by phenotypic characterization. The isolated strain HSB-15<sup>T</sup> was employed for the reduction of selected naphthyl ketones to their corresponding alcohols and a biosurfactant was isolated from its culture broth.</p><p><bold>Results:</bold> The analysis of the ITS and D1/D2 domains of the 26S rRNA gene revealed that strain HSB-15<sup>T</sup> is closely related to the type strain of <italic>Starmerella vitae</italic> (CBS 15147<sup>T</sup>) 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<sup>T</sup> and its closely related species and consequently, it was identified as a novel species, leading to the proposal of the name <italic>Starmerella cerana</italic> 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.</p><p><bold>Discussion:</bold> 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.</p>