Phyisiological, genomic and metabolic characterization of the oleaginous yeast Papiliotrema laurentii UFV-1
The interest on the use of microbial oils has increased for the production of fatty acids derivate products such as biofuels. The culture of oleaginous yeasts in abundant and low- cost raw materials is a promising alternative for biodiesel production. Due to the great microbial diversity found in Brazilian soils, the present project focused on the isolation of oleaginous yeasts from Rupestrian Fields soils and the study of the most prominent oleaginous yeast. The yeast Papiliotrema laurentii UFV-1 presented the lipids in the culture media with glucose and xylose as carbon sources. Unlike most oleaginous yeasts, lipid accumulation by P. laurentii UFV-1 begins at the exponential growth phase, presentin a lipid accumulation growth associated. Furthermore, evaluation of the profile for fatty acids may be considered suitable for biodiesel production. Relevant information was obtained after genomic analysis, such as the presence of a gene encoding for the malic enzyme NADP+-dependent and a single copy gene for the enzyme ATP citrate lyase, which is a key enzyme for oleaginous yeasts. We have found genes from alternative pathways for the lysine and leucine degradation, which may be alternative sources of acetyl-CoA for lipids accumulation. Analysis of expression and metabolic metabolism, including the NADP+-dependent malic enzyme, are the main sources of reducing the power for high accumulation of neutral lipids. Acetyl-CoA carboxylase activity is triggered over a period of increased lipid accumulation. We have found genes from alternative pathways for degradation of the amino acids leucine and lysine, which may be alternative sources of acetyl-CoA for lipid accumulation. Profile evaluation of gene expression and metabolism identified that the malic enzyme NADP +-dependent acts power reducing the great amount of neutral lipids accumulation. Interestingly, the expression profile for the ACC1 gene, which encodes acetyl-CoA carboxylase enzyme, decreased during the period of higher lipid accumulation. Furthermore, degradation of the amino acids lysine and leucine appear to contribute to acetyl-CoA synthesis in P. laurentii, according to the metabolic profile analysis. In general, metabolic pathways involved nitrogenous compounds were affected, according to the analysis pathway impact, which can be explained by the directional flow from carbon to lipid synthesis.
Leveduras - Fungos, Biodiesel, Óleos vegetais como combustível, Lipídios
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