Screening Identification and Characterization of a Strain of Candida Tropicalis

Jixiang Hu; Qingdong Li; Wenhua Tong; Yi Shen

doi:10.54097/53x8rz81

Authors

Jixiang Hu
Qingdong Li
Wenhua Tong
Yi Shen

DOI:

https://doi.org/10.54097/53x8rz81

Keywords:

Candida Tropicalis, Aroma Production, Volatile Compounds, Sauce-Flavor Daqu

Abstract

This study focused on the isolation and characterization of aromatic yeasts from Sauce-Flavor Daqu, a crucial fermentation starter for Chinese Baijiu production. Through systematic screening of 46 microbial isolates, we identified a strain with excellent aroma-producing capabilities. Initial liquid fermentation screening identified 12 strains with distinct aromatic profiles, with subsequent solid-state fermentation experiments confirming strain 12 as the most promising candidate, producing notable wine and floral-fruit aromas. Gas chromatography-mass spectrometry analysis revealed that the fermentation products from strain 12 contained predominantly alcohols (77.89 mg/kg) and esters (3.75 mg/kg), with phenylethanol (43.54 mg/kg) and isoamyl alcohol (29.64 mg/kg) as the major aromatic compounds. Morphological examination and 18S rDNA sequencing identified this strain as Candida tropicalis. Physiological characterization demonstrated that this yeast tolerated pH ranges from 4 to 9, sodium chloride concentrations up to 12%, and ethanol levels up to 7%. The growth curve analysis revealed that the strain entered exponential phase after 4 hours, reached stationary phase at 14-18 hours, and began declining after 18 hours. This study provides valuable insights into aroma-producing yeasts in traditional Chinese baijiu fermentation and identifies a potential candidate for flavor enhancement in fermented foods and beverages.

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