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Ergosterol production from molasses by genetically modified Saccharomyces cerevisiae
Xiuping He1, Xuena Guo, Nan Liu
1Laboratory of Yeast Molecular Genetics and Breeding, Institute of Microbiology, Chinese Academy of Sciences, Beijing, PR China.
Applied Microbiology and Biotechnology
|January 17, 2007
Summary
This study engineered yeast for enhanced ergosterol production using inexpensive cane molasses. Fed-batch fermentation achieved a significant yield of 1,707 mg/l ergosterol, a 3.1-fold increase over batch methods.
Area of Science:
- Biotechnology
- Metabolic Engineering
- Industrial Microbiology
Background:
- Ergosterol is a vital fungal metabolite with significant economic value.
- Recombinant Saccharomyces cerevisiae strains offer potential for improved ergosterol production.
Purpose of the Study:
- To enhance ergosterol production in a recombinant yeast strain using cane molasses.
- To optimize fermentation conditions for maximizing ergosterol yield.
Main Methods:
- Genetic engineering of Saccharomyces cerevisiae by overexpressing specific enzymes.
- Fermentation optimization using cane molasses as a carbon source in shake flask and bioreactor cultures.
- Investigating batch and fed-batch fermentation strategies, including agitation and nutrient feeding.
Main Results:
- A recombinant strain achieved 52.6 mg/g ergosterol in shake flask culture.
- Optimized conditions in a 5-l bioreactor (400 rpm) increased yield to 60.4 mg/l in batch mode.
- Fed-batch fermentation yielded 1,707 mg/l ergosterol, a 3.1-fold improvement over batch fermentation.
Conclusions:
- Combined overexpression of sterol reductases and acyltransferases significantly boosts ergosterol formation.
- Cane molasses is a cost-effective substrate for industrial ergosterol production.
- Fed-batch fermentation is a superior strategy for achieving high-density ergosterol yields in recombinant yeast.
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