title: Increased synthesis of α-tocopherol, paramylon and tyrosine by Euglena gracilis under conditions of high biomass production.
abstract: OBJECTIVE
  To analyse the production of different metabolites by dark-grown Euglena gracilis under conditions found to render high cell growth.
  
  
  RESULTS
  The combination of glutamate (5 g l(-1) ), malate (2 g l(-1) ) and ethanol (10 ml l(-1) ) (GM + EtOH); glutamate (7·15 g l(-1) ) and ethanol (10 ml l(-1) ); or malate (8·16 g l(-1) ), glucose (10·6 g l(-1) ) and NH(4) Cl (1·8 g l(-1) ) as carbon and nitrogen sources, promoted an increase of 5·6, 3·7 and 2·6-fold, respectively, in biomass concentration in comparison with glutamate and malate (GM). In turn, the production of α-tocopherol after 120 h identified by LC-MS was 3·7 ± 0·2, 2·4 ± 0·1 and 2 ± 0·1 mg [g dry weight (DW)](-1) , respectively, while in the control medium (GM) it was 0·72 ± 0·1 mg (g DW)(-1) . For paramylon synthesis, the addition of EtOH or glucose induced a higher production. Amino acids were assayed by RP-HPLC; Tyr a tocopherol precursor and Ala an amino acid with antioxidant activity were the amino acids synthesized at higher concentration.
  
  
  CONCLUSIONS
  Dark-grown E. gracilis Z is a suitable source for the generation of the biotechnologically relevant metabolites tyrosine, α-tocopherol and paramylon.
  
  
  CONCLUSIONS
  By combining different carbon and nitrogen sources and inducing a tolerable stress to the cell by adding ethanol, it was possible to increase the production of biomass, paramylon, α-tocopherol and some amino acids. The concentrations of α-tocopherol achieved in this study are higher than others reported previously for Euglena, plant and algal systems. This work helps to understand the effect of different carbon sources on the synthesis of bio-molecules by E. gracilis and can be used as a basis for future works to improve the production of different metabolites of biotechnological importance by this organism.
authors.affiliation: Departamento de Bioquímica, Instituto Nacional de Cardiología, México D.F., México. rodjos@cardiologia.org.mx
authors.forename: J S
authors.initials: JS
authors.lastname: Rodríguez-Zavala
authors.forename: M A
authors.initials: MA
authors.lastname: Ortiz-Cruz
authors.forename: G
authors.initials: G
authors.lastname: Mendoza-Hernández
authors.forename: R
authors.initials: R
authors.lastname: Moreno-Sánchez
mesh_terms: D018533:Biomass; D001709:Biotechnology / Q000379:methods; D003470:Culture Media; D005056:Euglena gracilis / Q000254:growth & development / Q000378:metabolism*; D005936:Glucans / Q000096:biosynthesis; D005947:Glucose / Q000378:metabolism; D014443:Tyrosine / Q000096:biosynthesis; D024502:alpha-Tocopherol / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005936:Glucans; D014443:Tyrosine; C003045:paramylon; D024502:alpha-Tocopherol; D005947:Glucose