Ventorim Rafaela Zandonade, Germano Vanessa Kely de Castro, Fontes Patrícia Pereira, da Silveira Wendel Batista
Department of Microbiology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.
Antonie Van Leeuwenhoek. 2023 Nov;116(11):1161-1170. doi: 10.1007/s10482-023-01874-5. Epub 2023 Sep 7.
Biodiesel is an interesting alternative to petroleum diesel as it is renewable, biodegradable, and has a low pollutant content. Yeast oils can be used for biodiesel production instead of edible oils, mitigating the use of arable land and water for biodiesel production. Maximum lipid accumulation is reached at 48 h of cultivation by the oleaginous yeast Papiliotrema laurentii UFV-1. Nevertheless, the effects of carbon and nitrogen concentrations on lipid accumulation, as well as the regulation of lipid metabolism in this yeast are still not well-characterised. Therefore, this work evaluated the effects of carbon and nitrogen concentrations on the lipid accumulation in P. laurentti, the expression of the ACC gene, and the activity of the enzyme acetyl-CoA carboxylase (ACCase) in different carbon:nitrogen ratios (C:N) and glucose concentrations. The variation of ammonium sulfate concentration did not affect the growth and lipid accumulation in P. laurentii UFV-1. On the other hand, glucose concentration remarkably influenced biomass and lipid production by this yeast. Therefore, the carbon concentration is more important than the nitrogen concentration for lipid production by P. laurentii UFV-1. Importantly, the levels of both ACC gene expression and ACCase activity were maximum during the late-exponential growth phase and decreased after reaching the highest lipid contents, which was easier evidenced during the accumulation and maximum lipid levels. As such, the reduction of ACCase enzyme activity seems to be related to the decrease in the expression level of the ACC gene.
生物柴油是石油柴油的一种有趣替代品，因为它可再生、可生物降解且污染物含量低。酵母油可用于生物柴油生产，而非食用油，从而减少生物柴油生产对耕地和水的使用。产油酵母劳伦替拟蝴蝶酵母UFV-1在培养48小时时达到最大脂质积累。然而，碳和氮浓度对脂质积累的影响，以及该酵母中脂质代谢的调控仍未得到很好的表征。因此，本研究评估了不同碳氮比（C:N）和葡萄糖浓度下，碳和氮浓度对劳伦替拟蝴蝶酵母脂质积累、ACC基因表达以及乙酰辅酶A羧化酶（ACCase）活性的影响。硫酸铵浓度的变化不影响劳伦替拟蝴蝶酵母UFV-1的生长和脂质积累。另一方面，葡萄糖浓度显著影响该酵母的生物量和脂质产量。因此，对于劳伦替拟蝴蝶酵母UFV-1的脂质生产而言，碳浓度比氮浓度更重要。重要的是，ACC基因表达水平和ACCase活性在指数生长后期均达到最高，在达到最高脂质含量后下降，这在脂质积累和最高脂质水平期间更容易得到证明。因此，ACCase酶活性的降低似乎与ACC基因表达水平的降低有关。
