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[The decrease of the activity of electron transfer chain of Torulopsis glabrata enhanced pyruvate productivity]
Li-Ming Liu1, Jian Chen, Hua-Zhong Li
1The Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi 214036, China. mingll@sytu.edu.cn
Wei Sheng Wu Xue Bao = Acta Microbiologica Sinica
|August 23, 2005
Summary
Mutant Torulopsis glabrata strains were developed to enhance pyruvate production. Adding acetaldehyde to mutant RD-17 significantly boosted pyruvate yield and reduced fermentation time.
Area of Science:
- Microbiology
- Biochemistry
- Metabolic Engineering
Background:
- Torulopsis glabrata is a yeast with potential for industrial applications.
- Respiratory-deficient mutants can exhibit altered metabolic pathways, potentially leading to enhanced product formation.
Purpose of the Study:
- To screen and characterize respiratory-deficient mutants of Torulopsis glabrata for improved pyruvate production.
- To investigate the metabolic and enzymatic changes in these mutants.
- To optimize fermentation conditions for enhanced pyruvate yield.
Main Methods:
- Ethidium bromide mutagenesis of Torulopsis glabrata CCTCC M202019.
- Screening for mutants with high pyruvate production and altered substrate assimilation (glucose, glycerol, acetate).
- Analysis of cytochromes, enzyme activities (ATPase, electron transport chain complexes), intracellular ATP content, and substrate consumption/product formation.
- Fermentation optimization using acetaldehyde addition.
Main Results:
- Three respiratory-deficient mutants (RD-16, RD-17, RD-18) were identified, showing decreased growth and ATP content but increased glucose consumption and pyruvate production per cell.
- Mutants RD-16 and RD-18 lacked cytochromes aa3 and b; mutant RD-17 lacked cytochrome b.
- Significant decreases in electron transport chain enzyme activities were observed.
- Addition of acetaldehyde to mutant RD-17 culture increased pyruvate production by 21.6% and shortened fermentation time from 62h to 48h.
Conclusions:
- Respiratory-deficient mutants of Torulopsis glabrata exhibit altered energy metabolism and enhanced pyruvate production.
- Acetaldehyde addition is an effective strategy to improve pyruvate yield and reduce fermentation time in specific mutants.
- These findings offer a promising approach for industrial pyruvate biosynthesis.
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