Olive oil additive enhances hyphal growth and triterpenes accumulation in submerged fermentation of Grifola frondosa.

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Citation abstract

Grifola frondosa, a famous mushroom worldwide, is highly valued for its multiple health benefits. However, the limited mycelial biomass and low triterpenes (GFTs) yield remain critical constraints for large-scale utilization of this fungus. In the present study, the effect of different vegetable oils on the liquid fermentation efficiency of G. frondosa was investigated, firstly. Furthermore, following optimization of the olive oil addition process and analysis of fermentation kinetics, the positive effect of olive oil on the hyphal growth and GFTs accumulation was identified. Further observations revealed that olive oil treatment led to increased flocculent hyphae, peroxisomes, mitochondria, and reactive oxygen species levels. Additionally, improvements in membrane integrity, lipid droplet accumulation, energy metabolism, and antioxidant capacity were found in the olive-oil-treated hyphae. Transcriptome sequencing and qRT-PCR results indicated that the expression of various genes involved in the peroxisome pathway was upregulated in the olive-oil-treated hyphae, suggesting that peroxisomes may participate in G. frondosa's response to olive oil. Overall, supplementing olive oil enhanced the growth and triterpenes production of G. frondosa. This study provides a strategy for improving the efficiency of industrial liquid fermentation for this mushroom.