Stimulatory effect of ethanol on libertellenone H biosynthesis by Arctic fungus Eutypella sp. D-1

Libertellenone H (1) was a promising antitumor diterpenoid isolated from Arctic fungus Eutypella sp. D-1, however, its production was very limited. In this study, we investigated the effects of ethanol on cell growth and libertellenone H production. The mycelium in ethanol-feeding cultures was fragmented and dispersed, and the titer of libertellenone H was remarkably increased to 4.88 mg l−1 in an optimal feeding manner, which was 16.4-fold higher than the control group. To provide an insight into the cell response to ethanol, genes critical to the libertellenone H biosynthesis were successfully cloned and their transcription levels were determined. The results suggested that the gene transcription levels of 3-hydroxy-3-methyl glutaric acyl coenzyme A reductase and geranylgeranyl diphosphate synthase were up-regulated by ethanol stimulation. The results from this study were helpful for further understanding of the ethanol function on diterpenes biosynthesis as well as developing more effective strategies for over-production of these desired secondary metabolites.