College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, 330013, China.
State Key Laboratory of Microbial Metabolism & School of Life Science and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, China.
J Ind Microbiol Biotechnol. 2020 Jan;47(1):49-61. doi: 10.1007/s10295-019-02244-9. Epub 2019 Dec 13.
Trichosporon cutaneum, a dimorphic oleaginous yeast, has immense biotechnological potential, which can use lignocellulose hydrolysates to accumulate lipids. Our preliminary studies on its dimorphic transition suggested that pH can significantly induce its morphogenesis. However, researches on dimorphic transition correlating with lipid biosynthesis in oleaginous yeasts are still limited. In this study, the unicellular yeast cells induced under pH 6.0-7.0 shake flask cultures resulted in 54.32% lipid content and 21.75 g/L dry cell weight (DCW), so lipid production was over threefold than that in hypha cells induced by acidic condition (pH 3.0-4.0). Furthermore, in bioreactor batch cultivation, the DCW and lipid content in unicellular yeast cells can reach 21.94 g/L and 58.72%, respectively, both of which were also more than twofold than that in hypha cells. Moreover, the activities of isocitrate dehydrogenase (IDH), malic enzyme (MAE), isocitrate lyase (ICL) and ATP citrate lyase (ACL) in unicellular cells were all higher than in the hyphal cells. In the meanwhile, the transcriptome data showed that the genes related to fatty acid biosynthesis, carbon metabolism and encoded Rim101 and cAMP-PKA signaling transduction pathways were significantly up-regulated in unicellular cells, which may play an important role in enhancing the lipid accumulation. In conclusion, our results provided insightful information focused on the molecular mechanism of dimorphic transition and process optimization for enhancing lipid accumulation in T. cutaneum.
出芽短梗霉是一种兼性油脂酵母，具有巨大的生物技术潜力，可利用木质纤维素水解物积累油脂。我们对其形态发生的初步研究表明，pH 值可以显著诱导其形态发生。然而，关于与油脂酵母中脂类生物合成相关的形态发生的研究仍然有限。在这项研究中，在 pH 6.0-7.0 摇瓶培养下诱导的单细胞酵母细胞导致 54.32%的脂质含量和 21.75 g/L 的干细胞重量（DCW），因此脂质产量比酸性条件（pH 3.0-4.0）下诱导的菌丝细胞高出三倍以上。此外，在生物反应器分批培养中，单细胞酵母细胞中的 DCW 和脂质含量分别达到 21.94 g/L 和 58.72%，均比菌丝细胞高出两倍以上。此外，单细胞细胞中的异柠檬酸脱氢酶（IDH）、苹果酸酶（MAE）、异柠檬酸裂解酶（ICL）和三磷酸腺苷柠檬酸裂解酶（ACL）的活性均高于菌丝细胞。同时，转录组数据显示，与脂肪酸生物合成、碳代谢相关的基因以及编码 Rim101 和 cAMP-PKA 信号转导途径的基因在单细胞细胞中显著上调，这可能在增强脂质积累中发挥重要作用。总之，我们的结果提供了有关出芽短梗霉形态发生的分子机制和增强脂质积累的过程优化的有见地的信息。
