Analysis of respiratory activity and carbon usage of a mutant of Azotobacter vinelandii impaired in poly-beta-hydroxybutyrate synthesis

作者：Jimenez Lucero; Castillo Tania; Flores Celia; Segura Daniel; Galindo Enrique; Pena Carlos^*

来源：Journal of Industrial Microbiology and Biotechnology, 2016, 43(8): 1167-1174.

DOI：10.1007/s10295-016-1774-2

• Azotobacter vinelandii
• Carbon usage
• Respiratory activity
• Poly(beta-hydroxybutyrate)
• Alginate production

In this study, the respiratory activity and carbon usage of the mutant strain of A. vinelandii AT6, impaired in poly-beta-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 %).

• 出版日期2016-8