Interrelationship of DOC Distribution in Metabolic Network to Growth Yield in Batch Culture

2000 ◽  
Vol 126 (1) ◽  
pp. 89-92
Author(s):  
Yu Liu ◽  
Joo-Hwa Tay
Keyword(s):  
Metabolic Network ◽  
Batch Culture ◽  
Growth Yield

scholarly journals The role of oxygen limitation in the formation of poly-β-hydroxybutyrate during batch and continuous culture of Azotobacter beijerinckii

1972 ◽  
Vol 128 (5) ◽  
pp. 1193-1201 ◽  
Author(s):  
P. J. Senior ◽  
G. A. Beech ◽  
G. A. F. Ritchie ◽  
E. A. Dawes
Keyword(s):  
Batch Culture ◽  
Growth Rates ◽  
Reducing Power ◽  
Growth Yield ◽  
Dry Weight ◽  
Oxygen Limitation ◽  
Co2 Production ◽  
Mineral Salts ◽  
Production Values ◽  
Chemostat Cultures

Azotobacter beijerinckii was grown in ammonia-free glucose–mineral salts media in batch culture and in chemostat cultures limited by the supply of glucose, oxygen or molecular nitrogen. In batch culture poly-β-hydroxybutyrate was formed towards the end of exponential growth and accumulated to about 74% of the cell dry weight. In chemostat cultures little poly-β-hydroxybutyrate accumulated in organisms that were nitrogen-limited, but when oxygen limited a much increased yield of cells per mol of glucose was observed, and the organisms contained up to 50% of their dry weight of poly-β-hydroxybutyrate. In carbon-limited cultures (D, the dilution rate,=0.035–0.240h−1), the growth yield ranged from 13.1 to 19.8g/mol of glucose and the poly-β-hydroxybutyrate content did not exceed 3.0% of the dry weight. In oxygen-limited cultures (D=0.049–0.252h−1) the growth yield ranged from 48.4 to 70.1g/mol of glucose and the poly-β-hydroxybutyrate content was between 19.6 and 44.6% of dry weight. In nitrogen-limited cultures (D=0.053–0.255h−1) the growth yield ranged from 7.45 to 19.9g/mol of glucose and the poly-β-hydroxybutyrate content was less than 1.5% of dry weight. The sudden imposition of oxygen limitation on a nitrogen-limited chemostat culture produced a rapid increase in poly-β-hydroxybutyrate content and cell yield. Determinations on chemostat cultures revealed that during oxygen-limited steady states (D=0.1h−1) the oxygen uptake decreased to 100μl h−1 per mg dry wt. compared with 675 for a glucose-limited culture (D=0.1h−1). Nitrogen-limited cultures had CO2 production values in situ ranging from 660 to 1055μl h−1 per mg dry wt. at growth rates of 0.053–0.234h−1 and carbon-limited cultures exhibited a variation of CO2 production between 185 and 1328μl h−1 per mg dry wt. at growth rates between 0.035 and 0.240h−1. These findings are discussed in relation to poly-β-hydroxybutyrate formation, growth efficiency and growth yield during growth on glucose. We suggest that poly-β-hydroxybutyrate is produced in response to oxygen limitation and represents not only a store of carbon and energy but also an electron sink into which excess of reducing power can be channelled.

Pigments and Citrinin Biosynthesis by Fungi Belonging to Genus Monascus

2005 ◽  
Vol 60 (1-2) ◽  
pp. 116-120 ◽  
Author(s):  
Emiliya Pisareva ◽  
Valentin Savov ◽  
Anna Kujumdzieva
Keyword(s):  
Carbon Source ◽  
Secondary Metabolites ◽  
Kinetic Parameters ◽  
Batch Culture ◽  
Growth Yield ◽  
Dry Weight ◽  
Yield Coefficient ◽  
Cultivation Conditions ◽  
Fungal Strains ◽  
Different Strains

Citrinin is a mycotoxin, which is produced by fungi belonging to the genus Monascus, known in biotechnology as producers of azaphilone pigments. The relation between biosynthesis of these secondary metabolites was investigated in different species of the genus Monascus in batch-culture at the following cultivation conditions: T = 28 °C, agitation 220 rpm, and a medium, which induce citrinin production, containing ethanol as a carbon source. The screening was carried out with 16 fungal strains and the biosynthesis of citrinin and pigments was monitored quantitatively at the standard conditions mentioned above. Some kinetic parameters of the process have been determined. The values of the growth yield coefficient YX/C were between 0.32 and 0.57. The amount of the extracellular red and orange pigments at the end of cultivation varied for the different strains between 0.09 and 1.33 OU/ mg dry weight, and 0.15 and 0.96 OU/mg dry weight, respectively. The amount of the total pigments measured was between 0.16 and 3.6 OU/mg dry weight, and between 0.21 and 3.39 OU/mg dry weight. The determined ratio 500 nm/400 nm, characterizing the pigment production, ranged between 0.60 and 1.06. Twelve of the investigated strains produced citrinin and pigments, two of them produced only pigments. Two strains were not able to produce neither pigments nor citrinin. Thus, the biosynthesis of citrinin appeared to be strain-specific and does not correlate with the pigments’ biosynthesis by the fungal strains belonging to the genus Monascus.

Molar growth yield of Nitrobacter agilis in batch culture

1986 ◽  
Vol 32 (7) ◽  
pp. 605-606 ◽  
Author(s):  
Yu-Li Tsai ◽  
Olli H. Tuovinen
Keyword(s):  
Batch Culture ◽  
Growth Yield ◽  
Dry Weight ◽  
Nitrobacter Agilis ◽  
Protein Measurement ◽  
Theoretical Amount

The molar growth yield (YG) of Nitrobacter agilis was determined with the use of 14CO2 fixation and protein measurement. A low YG of 0.220 g dry weight per mole nitrite oxidized was obtained. Assuming 4 or 6 mol ATP utilized per NAD(P)+ reduced, 10.8 or 14.5% of the theoretical amount of ATP available is utilized for the observed YG.

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