Non-Conventional Yeasts as Biofactories for Biotechnological Applications

Dear Colleagues,

Yeasts have been used in fermentation long before their physiology, metabolic potential, and extraordinary diversity were fully understood. Today, with more than a thousand recognized yeast species, it is increasingly evident that the traditional workhorse Saccharomyces cerevisiae accounts for only a small part of the biotechnological opportunities within the yeast kingdom.

In recent years, non-conventional yeasts have become versatile and resilient microbial cell factories that complement, and sometimes even surpass, traditional hosts. Many of these species naturally possess advantageous traits such as high secretory capacity, stress tolerance (including osmotic, oxidative, thermal, or inhibitor resistance), efficient utilization of diverse carbon sources (such as hydrophobic substrates, C5 sugars, or industrial by-products), and innate abilities to produce valuable metabolites. These qualities make them especially suitable for modern, sustainability-focused biotechnology, including the valorization of agrifood residues and side streams within the circular bioeconomy.

Simultaneously, rapid advancements in systems biology, synthetic biology, and metabolic engineering—including CRISPR-based genome editing, advanced pathway design, adaptive laboratory evolution, and enhanced bioprocess strategies—have sped up the development of non-conventional yeasts as customized production platforms. These applications include the production of enzymes, organic acids, polyols, lipids and single-cell oils, pigments and antioxidants, aroma compounds, recombinant proteins, and other high-value chemicals, along with whole-cell catalysis and innovative fermentation methods such as co-cultures and consolidated bioprocessing.

This Special Issue aims to gather the latest breakthroughs and serve as a platform for both fundamental and applied research on non-conventional yeasts as biofactories. We invite original research articles and reviews that deepen our understanding of these organisms and highlight their potential in industrial applications.

Potential topics include, but are not limited to, the following:

• Discovery and characterization of non-conventional yeast species and traits relevant to biotechnology;
• Strain development, metabolic engineering, and synthetic biology toolkits;
• Production of enzymes, organic acids, polyols, lipids (SCO), pigments, flavors, aromas, and other valuable metabolites;
• Recombinant protein expression and secretion, host engineering, and glycoengineering strategies;
• Whole-cell biocatalysis and pathway or host optimization for specialty chemicals;
• Stress tolerance and robustness engineering (inhibitors, pH, temperature, osmotic stress, solvents);
• Bioprocess design, scale-up, fermentation strategies, and downstream processing considerations;
• Waste and side-stream valorization (agri-food, oleochemical, lignocellulosic, glycerol, wastewater-derived substrates);
• Mixed cultures, co-cultivation, and process intensification for improved productivity;
• Biosafety, regulatory aspects, and application-driven studies (food, feed, pharma, materials).

Dr. Bartłomiej Zieniuk
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-anonymized peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fermentation is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2100 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• non-conventional yeasts
• yeast cell factories
• metabolic engineering
• synthetic biology
• systems biology
• whole-cell biocatalysis
• recombinant protein expression
• secretion
• enzymes
• organic acids
• polyols
• single-cell oils (SCO)
• single-cell proteins (SCP)
• pigments
• flavors and aromas
• stress tolerance
• waste valorization
• circular bioeconomy
• bioprocess engineering
• fermentation scale-up
• co-culture fermentation
• downstream processing