Flux limitations in the ortho pathway of benzoate degradation of Alcaligenes eutrophus: metabolite overflow and induction of the meta pathway at high substrate concentrations

Article Abstract:

Low levels of benzoate (less than 5 mM) are capable of supporting growth and high yields of biomass formation in Alcaligenes eutrophus. The specific growth rate decreases as the initial benzoate concentration increases (up to 40 mM) but benzoate consumption is unaltered. High concentrations of 1,2-dihydro-1,2- dihydroxybenzoate and catechol get accumulated, the former causing induction of the meta pathway for catechol degradation. This accounts for 20% of the total catechol flux to the central mechanism. Growth and benzoate degradation reduce with 55mM benzoate.

Microbial metabolism, Bacterial growth

Repression of phenol catabolism by organic acids in Ralstonia eutropha

Article Abstract:

A study was conducted to determine the mechanisms that lead to catabolite repression phenomena in pseudomonads such as Ralstonia eutropha when an organic acid and an aromatic compound are present at the same time. Among the findings are that benzoate is the preferred substrate and that the catabolism of acetate is repressed at the transcriptional level. This latter finding suggests that there are common regulatory mechanisms in R. eutropha and that hierarchy of substrate utilization rules carbon source preferences.

Metabolic regulation, Organic acids

Carbon and energy flux constraints in continuous cultures of Alcaligenes eutrophus grown on phenol

Article Abstract:

A study designed to identify the factors that control the growth efficiency and substrate degradation rates in Alcaligenes eutrophus grown on phenol was conducted. This requires the evaluation of the pseudomonad's growth behavior in continuous cultures. Results show that the accumulation of polyhydroxybutyrate was caused by the fixed stoichiometry of the meta pathway of phenol degradation.

Bacterial genetics