Fungal dynamic changes in naturally fermented 'Kyoho' grape juice

Area of Science:

• Viticulture and Enology
• Microbiology
• Metagenomics

Background:

• The 'Kyoho' grape is widely cultivated in China, yet its winemaking potential and microbial dynamics during fermentation remain understudied.
• Understanding fungal community shifts is crucial for optimizing wine fermentation processes and quality.

Purpose of the Study:

• To investigate the dynamic changes in fungal species composition and metabolic pathways during the natural fermentation of 'Kyoho' grape must.
• To identify dominant yeast species and their potential roles in 'Kyoho' wine production.

Main Methods:

• High-throughput sequencing was employed to analyze fungal communities in 'Kyoho' grape fermentation broth at four distinct time points (Days 1, 3, 5, and 15).
• Differential metabolic pathway analysis was conducted to understand the functional changes within the fungal community.
• Control check (CK) samples were used for comparative analysis.

Main Results:

• A total of 137 fungal species were detected in the natural fermentation broth, significantly more than in the control.
• 66 differential metabolic pathways were enriched, with 41 up-regulated, including key biosynthesis and degradation pathways.
• 'Pichia kluyveri', 'Pichia membranifaciens', and 'Citeromyces matritensis' emerged as dominant yeast species in the later fermentation stages.

Conclusions:

• Fungal community composition and metabolic activity dynamically change throughout 'Kyoho' grape wine fermentation.
• Specific yeast species, including 'Pichia kluyveri', 'P. membranifaciens', and 'C. matritensis', are identified as key players in later fermentation stages.
• These dominant yeasts hold significant potential for future 'Kyoho' wine industry development.