Engineering Cell Wall Integrity Enables Enhanced Squalene Production in Yeast

Area of Science:

• Biotechnology
• Microbial Engineering
• Synthetic Biology

Background:

• Lipophilic compound production in microbes is limited by product toxicity to host cells.
• Engineering cell walls can increase tolerance to lipophilic compounds, mitigating host cell damage.
• Squalene, a model lipophilic compound, production in yeast can cause decreased membrane rigidity and cell lysis.

Purpose of the Study:

• To investigate if cell wall engineering can enhance lipophilic compound production.
• To determine if activating the cell wall integrity (CWI) pathway can restore membrane rigidity and improve squalene production in a squalene-overproducing yeast strain.
• To assess the role of Ecm33 in CWI and its impact on squalene production and cell stress tolerance.

Main Methods:

• Utilized a previously constructed squalene-overproducing yeast strain (SQ).
• Engineered the SQ strain to activate the cell wall integrity (CWI) pathway.
• Investigated the role of Ecm33, a CWI pathway regulator, through gene deletion.
• Assessed membrane rigidity, cell lysis, and squalene production efficiency.

Main Results:

• The SQ strain exhibited decreased membrane rigidity and increased cell lysis.
• Activating the CWI pathway restored membrane rigidity and enhanced squalene production efficiency.
• Deletion of ECM33 in the SQ strain restored membrane rigidity, improved stress tolerance, suppressed cell lysis, and increased squalene production by approximately 12%.

Conclusions:

• Engineering the yeast cell wall is a viable strategy to enhance lipophilic compound production.
• Modulating cell wall integrity, particularly through Ecm33 regulation, improves host cell tolerance to lipophilic compounds.
• This approach offers a promising method for improving the physiological functions of industrial microbial strains for biotechnological applications.