title: Different responses in the expression of alginases, alginate polymerase and acetylation genes during alginate production by Azotobacter vinelandii under oxygen-controlled conditions.
abstract: Alginate production and gene expression of genes involved in alginate biosynthesis were evaluated in continuous cultures under dissolved oxygen tension (DOT) controlled conditions. Chemostat at 8% DOT showed an increase in the specific oxygen uptake rate [Formula: see text] from 10.9 to 45.3 mmol g-1h-1by changes in the dilution rate (D) from 0.06 to 0.10 h-1, whereas under 1% DOT the [Formula: see text] was not affected. Alginate molecular weight was not affected by DOT. However, chemostat at 1% DOT showed a downregulation up to 20-fold in genes encoding both the alginate polymerase (alg8, alg44), alginate acetylases (algV, algI) and alginate lyase AlgL. alyA1 and algE7 lyases gene expressions presented an opposite behavior by changing the DOT, suggesting that A. vinelandii can use specific depolymerases depending on the oxygen level. Overall, the DOT level have a differential effect on genes involved in alginate synthesis, thus a gene expression equilibrium determines the production of alginates of similar molecular weight under DOT controlled.
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Casilla, 4059, Valparaíso, Chile. alvaro.diaz@pucv.cl.
authors.forename: Alvaro
authors.identifier: 0000-0002-0922-8648
authors.initials: A
authors.lastname: Díaz-Barrera
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Casilla, 4059, Valparaíso, Chile.
authors.forename: Nataly
authors.initials: N
authors.lastname: Maturana
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.|Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
authors.forename: Ivette
authors.initials: I
authors.lastname: Pacheco-Leyva
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Casilla, 4059, Valparaíso, Chile.
authors.forename: Irene
authors.initials: I
authors.lastname: Martínez
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Casilla, 4059, Valparaíso, Chile.|CREAS CONICYT Regional GORE Valparaíso R0GI1004, Av. Universidad, Curauma, Chile.
authors.forename: Claudia
authors.initials: C
authors.lastname: Altamirano
mesh_terms: D000107:Acetylation; D000464:Alginates; D016948:Azotobacter vinelandii / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D020723:Glucuronic Acid / Q000096:biosynthesis; D006603:Hexuronic Acids; D008970:Molecular Weight; D010100:Oxygen / Q000378:metabolism; D011133:Polysaccharide-Lyases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000464:Alginates; D001426:Bacterial Proteins; D003470:Culture Media; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase; D010100:Oxygen
keywords: Alginate; Continuous culture; Gene expression; Oxygen control