Enhanced ganoderic acids production by using thermotolerant Ganoderma tsugae at high-temperature liquid cultivation

Area of Science:

• Biotechnology
• Mycology
• Biochemistry

Background:

• Ganoderic acids (GAs) are triterpenoids from Ganoderma species with anticancer potential.
• Low natural yield of GAs in Ganoderma tsugae limits its application.
• Heat stress can enhance GA production, but requires thermotolerant strains.

Purpose of the Study:

• To develop thermotolerant Ganoderma tsugae mutants using atmospheric and room temperature plasma (ARTP) mutagenesis.
• To enhance ganoderic acid (GA) production through high-temperature cultivation of developed mutants.
• To investigate the physiological and molecular mechanisms of thermotolerance and enhanced GA biosynthesis.

Main Methods:

• Generated Ganoderma tsugae mutants using ARTP mutagenesis.
• Screened for thermotolerant mutants capable of growth at 35°C.
• Conducted physiological (growth, biomass, membrane fluidity, metabolite levels) and transcriptional analyses (gene expression).

Main Results:

• Identified a superior thermotolerant mutant, GT9, with significantly increased mycelial growth and biomass at 35°C compared to wild-type (WT).
• GT9 exhibited enhanced membrane fluidity and elevated levels of key metabolites like lanosterol, squalene, and ergosterol.
• GT9 showed upregulated expression of GA biosynthetic genes and heat shock proteins, leading to increased GA production at 35°C.

Conclusions:

• ARTP-generated thermotolerant G. tsugae mutants, like GT9, are effective for high-temperature fermentation.
• This strategy significantly enhances ganoderic acid production, offering industrial application advantages.
• The study elucidates mechanisms of improved GA biosynthesis under heat stress, paving the way for optimized fungal cultivation.