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Updated: Jul 3, 2026
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Directed Evolution Method in Saccharomyces cerevisiae: Mutant Library Creation and Screening
Published on: April 1, 2016
Adaptively evolved chitin overproduction in Saccharomyces cerevisiae.
An Nguyen1, Merja Penttilä2, Alexander D Frey1
1Department of Bioproducts and Biosystems, Aalto University, Espoo, Finland.
Metabolic Engineering
|July 1, 2026
Summary
Adaptive laboratory evolution in Saccharomyces cerevisiae increased chitin production by up to sevenfold. This advancement in fungal biotechnology offers a sustainable, animal-free source of chitin for industrial applications.
Area of Science:
- Biotechnology and Bioprocess Engineering
- Molecular and Cellular Biology
- Biochemistry and Biomaterials
Background:
- Chitin, a biopolymer with desirable properties like biocompatibility and biodegradability, holds potential for various applications.
- Economical biotechnological production of chitin using fungi, like Saccharomyces cerevisiae, is hindered by low intracellular chitin content.
- Chitin content is regulated by complex genetic pathways, making direct strain improvement challenging.
Purpose of the Study:
- To enhance chitin overaccumulation in Saccharomyces cerevisiae through adaptive laboratory evolution (ALE).
- To identify genetic variants responsible for increased chitin production.
- To establish a foundation for developing industrial strains for animal-free chitin production.
Main Methods:
- Adaptive laboratory evolution (ALE) of Saccharomyces cerevisiae lineages in the presence of caspofungin (CAS).
- Whole genome sequencing of evolved strains to identify single-nucleotide variants.
- Re-engineering of identified genetic variants into the wild-type strain to validate their effect on chitin content.
Main Results:
- ALE successfully selected for strains with significantly increased chitin content, with some lineages tolerating high CAS concentrations.
- Whole genome sequencing identified 88 unique single-nucleotide variants across 43 coding sequences in evolved populations.
- Re-engineering specific variants (Fks1 p.Pro647Arg, Fks2 p.Arg1203*, and Ecm21 p.Glu642*) led to a sevenfold increase in cellular chitin content, independent of CAS tolerance.
Conclusions:
- Adaptive laboratory evolution is an effective strategy for enhancing chitin production in Saccharomyces cerevisiae.
- Specific genetic variants, particularly in FKS1, FKS2, and ECM21, are key drivers of chitin overaccumulation.
- The identified variants provide a basis for developing industrially viable, animal-free chitin production using engineered yeast strains.
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