Hierarchical amino acid utilization and its influence on fermentation dynamics: rifamycin B fermentation using Amycolatopsis mediterraneiS699, a case study

Table 1 Stoichiometric coefficients for batch fermentation of rifamycin B using Amycolatopsis maditerranei S699

Stoichiometric coefficients^a (moles of substrate. C-mole of biomass^-1)
Amino acids	Glucose and amino acids	Glucose and ammonia
Y_1,1,k= 0.51	Y_2,1,k= 0.13	Y_3,2 = 0.35
Y_1,3 = 1.30	Y_2,2 = 0.24	Y_3,6 = 0.16
Y_1,6 = 0.85	Y_2,3 = 1.10

^a Amycolatopsis mediterranei S699 was cultivated in two media compositions. (i) Containing mixture of amino acids at a concentraton of 3.25 mM each and (ii) medium (i) supplemented wih glucose (80 g.l^-1). Both the media were supplemented with 11 gl^-1 CaCO₃, 1 gl^-1 KH₂PO₄, 1 gl^-1 MgSO₄, 0.01 gl^-1 FeSO₄, 0.05 gl^-1 ZnSO4 and 0.003 gl^-1 COCl₂. Samples were taken at regular intervals to estimate concentrations of amino acids, rifamycin B, biomass, residual ammonia and glucose. Online data such as vent CO₂ and dissolved oxygen was obtained from exit gas analyzer. The offline and online data was further used to estimate stoichiometric coefficients on respective substrate assimilation modes. Y i,j are stoichiometric coefficients where i is reaction number (refer equations in materials and methods) and j is the substrate for example : Amino acid (1) where k represents 20 different amino acids, glucose (2), CO₂ (3), O₂ (4), H₂O (5), Ammonia (6).

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