title: Analysis of respiratory activity and carbon usage of a mutant of Azotobacter vinelandii impaired in poly-β-hydroxybutyrate synthesis.
abstract: In this study, the respiratory activity and carbon usage of the mutant strain of A. vinelandii AT6, impaired in poly-β-hydroxybutyrate (PHB) production, and their relationship with the synthesis of alginate were evaluated. The alginate yield and the specific oxygen uptake rate were higher (2.5-fold and 62 %, respectively) for the AT6 strain, compared to the control strain (ATCC 9046), both in shake flasks cultures and in bioreactor, under fixed dissolved oxygen tension (1 %). In contrast, the degree of acetylation was similar in both strains. These results, together with the analysis of carbon usage (% C-mol), suggest that in the case of the AT6 strain, the flux of acetyl-CoA (precursor molecule for PHB biosynthesis and alginate acetylation) was diverted to the respiratory chain passing through the tricarboxylic acids cycle, and an important % C-mol was directed through alginate biosynthesis, up to 25.9 % and to a lesser extent, to biomass production (19.7 %).
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Post. 510-3, 62250, Cuernavaca, Morelos, Mexico.
authors.forename: Lucero
authors.initials: L
authors.lastname: Jiménez
authors.affiliation: Centro de Investigaciones en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa C.P, 62209, Cuernavaca, Morelos, Mexico.
authors.forename: Tania
authors.initials: T
authors.lastname: Castillo
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Post. 510-3, 62250, Cuernavaca, Morelos, Mexico.
authors.forename: Celia
authors.initials: C
authors.lastname: Flores
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Post. 510-3, 62250, Cuernavaca, Morelos, Mexico.
authors.forename: Daniel
authors.initials: D
authors.lastname: Segura
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Post. 510-3, 62250, Cuernavaca, Morelos, Mexico.
authors.forename: Enrique
authors.initials: E
authors.lastname: Galindo
authors.affiliation: Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Post. 510-3, 62250, Cuernavaca, Morelos, Mexico. carlosf@ibt.unam.mx.
authors.forename: Carlos
authors.initials: C
authors.lastname: Peña
mesh_terms: D000105:Acetyl Coenzyme A / Q000378:metabolism; D000464:Alginates; D016948:Azotobacter vinelandii / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D020723:Glucuronic Acid / Q000096:biosynthesis; D006603:Hexuronic Acids; D006885:Hydroxybutyrates / Q000378:metabolism; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism; D000094122:Polyhydroxybutyrates
chemical_list: D000105:Acetyl Coenzyme A; D000464:Alginates; D002244:Carbon; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006885:Hydroxybutyrates; D010100:Oxygen; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Alginate production; Azotobacter vinelandii; Carbon usage; Poly(β-hydroxybutyrate); Respiratory activity