Different responses in the expression of alginases, alginate polymerase and acetylation genes during alginate production by Azotobacter vinelandii under oxygen-controlled conditions

Diaz-Barrera, A

Keywords: Alginate Continuous culture Oxygen control Gene expression

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 (q O 2 ) (qO2) from 10.9 to 45.3 mmol g−1 h−1 by changes in the dilution rate (D) from 0.06 to 0.10 h−1, whereas under 1% DOT the q O 2 qO2 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.

Más información

Título de la Revista: JOURNAL OF INDUSTRIAL MICROBIOLOGY AND BIOTECHNOLOGY
Editorial: Springer
Fecha de publicación: 2017
Idioma: English
Notas: ISI