Fig. 3From: Understanding the interplay of carbon and nitrogen supply for ectoines production and metabolic overflow in high density cultures of Chromohalobacter salexigens The link between nitrogen metabolism and ectoine synthesis. Effect of the ect − mutation on the growth of C. salexigens. a The strains CHR61 (wild type, black symbols) and CHR62 (ect − mutant, white symbols) were grown in M63 glucose minimal medium with 0.75 M NaCl. b The defective growth phenotype of the mutant CHR62 strain was recovered upon growth in M63 glucose minimal medium supplemented with 20 mM ectoine as the sole nitrogen source. c Effect of the nitrogen source selected for the growth of C. salexigens. The wild type CHR61 strain was grown in in M63 minimal medium with 2.5 M NaCl and supplemented with 30 mM ammonium (black circles), 20 mM alanine (white triangles), 20 mM glutamate (black triangles) or 20 mM ectoine (white circles) as the sole nitrogen source. d Link between central metabolism and the ectoines biosynthesis pathway in C. salexigens [6]. Cofactors produced and/or consumed in each pathway are indicated. Glucose is transformed into pyruvate by the Entner–Doudoroff pathway and ectoines are synthesized from oxaloacetate and acetyl-CoA. e Ammonium assimilation pathways in C. salexigens: glutamate dehydrogenase (GDH) and glutamine synthetase/glutamate synthase (GS/GOGAT). Alanine is catabolized by oxidative deamination catalyzed by alanine dehydrogenase (AlaDH)*. f Overall stoichiometry of ectoine biosynthesis in C. salexigens as a function of the ammonium assimilation pathway used. Ectoine biosynthesis from glucose leads to net consumption of 1 mol of ATP if ammonia is assimilated through GDH and 3 mol of ATP if it is assimilated through the GS/GOGAT pathway**. * Genes encoding glutamate dehydrogenase (Csal1340) and alanine dehydrogenase (Csal2966) have been annotated in the genome of C. salexigens [23]. Five genes encoding putative glutamine synthetases are annotated: Csal0777, Csal1181, Csal1192, Csal0243, Csal0679. Glutamate synthase is a heterodimeric protein composed of two different subunits encoded by gltB (Csal0615) and gltD (Csal0616) genes. ** Hydroxyectoine biosynthesis from glucose needs additionally 1 mol NADH and 1 mol GTP due to the transformation of α-ketoglutarate into succinate by ectoine hydroxylaseBack to article page