Theoretical conversion yields for penicillin synthesis

Abstract

The efficiency of conversion of the carbon-energy source to product is of primary importance in many fermentation processes. In order to assess the efficiency of a process, one must know how close the actual conversion yield is to the theoretical maximum. Theoretical conversion yields are useful, therefore, as guides in improving a process. This knowledge is particularly important today because the cost of raw materials is rapidly rising. In this study, the biochemical pathway of penicillin synthesis was used to estimate the theoretical yield of penicillin from glucose, ammonia, and sulfate. These values are compared with experimental data from the literature. An analysis of the role of glucose in the synthesis of cell mass and penicillin and in the maintenance of cells makes it possible to assess the efficiency of carbon-source utilization and to direct further advances in penicillin fermentations.

Energetics of growth and penicillin production in a high-producing strain ofPenicillium chrysogenum

“…If this value is realistic, it has important consequences for the maximum theoretical yield of penicillin on the C source, which would be much lower than previously calculated values based on the present knowledge of the ATP stoichiometry of the penicillin biosynthesis pathway (Cooney and Acevedo, 1977;Hersbach et al, 1984;Jørgensen et al, 1995).…”

“…From this good agreement between calculated and observed yields it can be inferred that the assumption we used for the estimation of the ATP stoichiometry coefficients (i.e., that these coefficients are independent of the growth rate and the substrate used), leads to accurate yield calculations for all growth conditions used (substrates and growth rates). Christensen et al (1995) 0.51 0.028 Ryu and Hospodka (1980) 0.45 0.024 Mason and Righelato (1976) 0.48 0.023 Righelato et al (1968) 0.45 0.022 Jørgensen et al (1995) 0.43-0.50 Hersbach et al (1984) 0.47 Cooney and Acevedo (1977) 0.60…”

“…Several workers used stoichiometric models to calculate maximum theoretical yields of penicillin on glucose (Cooney and Acevedo, 1977;Hersbach et al, 1984;Jør-gensen et al, 1995). In these studies, the energetics of penicillin formation has been based on the well-known biochemistry of the biosynthesis pathway.…”

Oxidation of methanol by the yeast, Pichia pastoris. Purification and properties of the alcohol oxidase.

“…In this case the energy of methanol oxidation is available to the cell.3,4) The higher yields observed with bacteria as compared to yeasts were attributed to the first step of methanol oxidation. 5,6) Since the yield on methanol of the yeast, Pichia pastoris IFP 206, was high compared to other yeasts (0.42g of cell per g of methanol) the question was raised whether the oxidation of methanol is catalyzed by an oxidase or a dehydrogenase. Formaldehyde formed by the oxidation of methanol is further oxidized to carbon dioxide by a two steps reaction involving formal dehyde (E.C.…”

Reversion of l-lysine inhibition of penicillin G biosynthesis by 6-oxopiperidine-2-carboxylic acid in Penicillium chrysogenum PQ-96

“…The costs of penicillin G production depend on the terminal balance of six possible ways of penicillin G biosynthesis (Cooney and Acevedo 1977;Hersbach et al 1984). The m a x i m u m theoretical conversion yield was 1980 units or 1100 units of penicillin G per mg of glucose, depending on whether L-a-aminoadipic acid (L-AAA) was recycled or not.…”