This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Research
Jie Sun
Zhejiang University of Technology
Corresponding Author
Tingheng Zhu
Zhejiang University of Technology
Corresponding Author
ORCiD: https://orcid.org/0000-0003-2251-9471
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background
The market demand for natural 2-phenylethanol (2-PE) continues to increase. Saccharomyces cerevisiae can synthesize 2-PE through the Ehrlich pathway. There are few studies on the improvement of the diploid industrial strains of S. cerevisiae by gene editing technology. There is no report on the comparison of genetic manipulation effect among S.cerevisiae strains with different 2-PE yield background, and the study on knockout of 2-PE downstream product synthesis gene and its effect on the yield of 2-PE have not been found.
Results
The CRISPR/CAS9 system with high efficiency for diploid S.cerevisiae CWY132 strain for industrial production of 2-PE was constructed. When the length of the homology arm of donor DNA is increased from 60bp to 500bp, the efficiency of gene editing increased from 0–100%. Using CRISPR/CAS9 technology, the branched acetaldehyde dehydrogenase genes ALD2 and ALD3 and the terminal acetyltransferase gene ATF1 in the Ehrlich pathway of S.cerevisiae strains with different 2-PE yields were knocked out. The results showed that in the high-yielding CWY-132 strain, the 2-PE yield decreased from 3.50 g/L to 1.65 g/L when double ALD2 and ALD3 were knocked out, a decrease of 52.8%. When ATF1 was knocked out, the yield of 2-PE decreased to 0.83 g/L, a decrease of 76.2%; In the low-yielding strain PK-2C, the yield of 2-PE increased from 0.21 g/L to 1.20 g/L when ALD2 was knocked out, an increase of 471%. When ATF1 was knocked out, the yield of 2-PE increased to 0.45g/L, an increase of 114%. The results show that the same genetic manipulation strategy for strains with different 2-PE yeilds backgrounds produces significantly different or even opposite effects. In addition, we found that the insufficient supply of NADH in cells can significantly affect the production of 2-PE, and the tolerance of cells to 2-PE is also a key factor that limits the further increase of 2-PE production in high-yielding strain.
Conclusions
This study shows that the length of the Donor DNA homology arm is a key factor affecting the efficiency of CRISPR/CAS9 gene editing in industrial diploid S. cerevisiae strains. Our result also shows that it is not feasible to increase the 2-PE production in high-yielding strains by blocking the branch pathway in the Ehrlich pathway. Breakthrough in the 2-PE yield of the high-yielding strains requires improved strains’ tolerance to 2-PE and increase the cellular NADH level.
Keywords
Ehrlich pathway, 2-phenylethanol, ATF1, ALD3, CRISPR/CAS9, Saccharomyces cerevisiae
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This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Research
Jie Sun
Zhejiang University of Technology
Corresponding Author
Tingheng Zhu
Zhejiang University of Technology
Corresponding Author
ORCiD: https://orcid.org/0000-0003-2251-9471
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 01 Apr, 2021
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background
The market demand for natural 2-phenylethanol (2-PE) continues to increase. Saccharomyces cerevisiae can synthesize 2-PE through the Ehrlich pathway. There are few studies on the improvement of the diploid industrial strains of S. cerevisiae by gene editing technology. There is no report on the comparison of genetic manipulation effect among S.cerevisiae strains with different 2-PE yield background, and the study on knockout of 2-PE downstream product synthesis gene and its effect on the yield of 2-PE have not been found.
Results
The CRISPR/CAS9 system with high efficiency for diploid S.cerevisiae CWY132 strain for industrial production of 2-PE was constructed. When the length of the homology arm of donor DNA is increased from 60bp to 500bp, the efficiency of gene editing increased from 0–100%. Using CRISPR/CAS9 technology, the branched acetaldehyde dehydrogenase genes ALD2 and ALD3 and the terminal acetyltransferase gene ATF1 in the Ehrlich pathway of S.cerevisiae strains with different 2-PE yields were knocked out. The results showed that in the high-yielding CWY-132 strain, the 2-PE yield decreased from 3.50 g/L to 1.65 g/L when double ALD2 and ALD3 were knocked out, a decrease of 52.8%. When ATF1 was knocked out, the yield of 2-PE decreased to 0.83 g/L, a decrease of 76.2%; In the low-yielding strain PK-2C, the yield of 2-PE increased from 0.21 g/L to 1.20 g/L when ALD2 was knocked out, an increase of 471%. When ATF1 was knocked out, the yield of 2-PE increased to 0.45g/L, an increase of 114%. The results show that the same genetic manipulation strategy for strains with different 2-PE yeilds backgrounds produces significantly different or even opposite effects. In addition, we found that the insufficient supply of NADH in cells can significantly affect the production of 2-PE, and the tolerance of cells to 2-PE is also a key factor that limits the further increase of 2-PE production in high-yielding strain.
Conclusions
This study shows that the length of the Donor DNA homology arm is a key factor affecting the efficiency of CRISPR/CAS9 gene editing in industrial diploid S. cerevisiae strains. Our result also shows that it is not feasible to increase the 2-PE production in high-yielding strains by blocking the branch pathway in the Ehrlich pathway. Breakthrough in the 2-PE yield of the high-yielding strains requires improved strains’ tolerance to 2-PE and increase the cellular NADH level.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
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