title: Physiology and gene expression profiles of Dekkera  bruxellensis in response to carbon and nitrogen availability.
abstract: The assimilation of nitrate, a nitrogenous compound, was previously described as an important factor favoring Dekkera bruxellensis in the competition with Saccharomyces cerevisiae for the industrial sugarcane substrate. In this substrate, nitrogen sources are limited and diverse, and a recent report showed that amino acids enable D. bruxellensis to grow anaerobically. Thus, understanding the regulation of nitrogen metabolism is one fundamental aspect to comprehend the competiveness of D. bruxellensis in the fermentation environment. In the present study, we evaluated the physiological and transcriptional profiles of D. bruxellensis in response to different carbon and nitrogen supplies to determine their influence on growth, sugar consumption, and ethanol production. Besides, the expression of genes coding for nitrogen permeases and enzymes involved in the biosynthesis of glutamate and energetic metabolism were investigated under these conditions. Our data revealed that genes related to nitrogen uptake in D. bruxellensis are under the control of nitrogen catabolite repression. Moreover, we provide indications that glutamate dehydrogenase and glutamate synthase may switch roles as the major pathway for glutamate biosynthesis in D. bruxellensis. Finally, our data showed that in nonoptimal growth conditions, D. bruxellensis leans toward the respiratory metabolism. The results presented herein show that D. bruxellensis and S. cerevisiae share similar regulation of GDH–GOGAT pathway, while D. bruxellensis converts less glucose to ethanol than S. cerevisiae do when nitrogen is limited. The consequence of this particularity to the industrial process is discussed.
authors: Will
authors: W
authors: de Barros Pita
authors: Denise Castro
authors: DC
authors: Silva
authors: Diogo Ardaillon
authors: DA
authors: Simões
authors: Volkmar
authors: V
authors: Passoth
authors: Marcos Antonio
authors: MA
authors: de Morais
mesh_terms: D000222:Adaptation, Physiological; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism*; D055167:Dekkera / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D004734:Energy Metabolism; D000431:Ethanol / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D009584:Nitrogen / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D000431:Ethanol; D002244:Carbon; D009584:Nitrogen