Candida tropicalis sp. Nov., a novel, zinc-enriched yeast species found in China

Abstract Zinc is one of the most important trace elements and deficiency can lead to significant clinical complications. Microbial transformation is one of the most important methods used to supplement organic zinc and there may be some naturally occurring microorganisms that have both higher zinc tolerances and transformation capabilities. In this study, microorganisms which displayed such characteristics were widely screened, and a strain designated T-A was found. Morphological and molecular determination demonstrated that T-A is closely related to Candida tropicalis with 87% of 18S rDNA homology, with a G+C content measured by RP-HPLC of 88.42%. Candida tropicalis sp. T-A strains were shown to grow and transform zinc best at pH5 in medium with a zinc ion concentration of 8000 μg/mL at 28 °C for 121 hours. Our results showed C. tropicalis sp. T-A’s zinc content was 19.153 mg/g dry weight, with a relative bioavailability in rats of 173% when compared with traditional zinc supplements. Our study suggests that C. tropicalis sp. T-A could be exploited for use as a potential zinc supplement.