Effects of methyl oleate and microparticle-enhanced cultivation on echinocandin B fermentation titer.

Echinocandin B (ECB) is a key precursor of antifungal agent Anidulafungin, which has demonstrated clinical efficacy in patients with invasive candidiasis. In this study, the effects of microparticle-enhanced cultivation and methyl oleate on echinocandin B fermentation titer were investigated. The results showed that the titer was significantly influenced by the morphological type of mycelium, and mycelium pellet was beneficial to improve the titer of this secondary metabolism. First, different carbon sources were chosen for the fermentation, and methyl oleate achieved the highest echinocandin B titer of 2133 ± 50 mg/L, which was two times higher than that of the mannitol. The study further investigated the metabolic process of the fermentation, and the results showed that L-threonine concentration inside the cell could reach 275 mg/L at 168 h with methyl oleate, about 2.5 times higher than that of the mannitol. Therefore, L-threonine may be a key precursor of echinocandin B. In the end, a new method of adding microparticles for improving the mycelial morphology was used, and the addition of talcum powder (20 g/L, diameter of 45 µm) could make the maximum titer of echinocandin B reach 3148 ± 100 mg/L.