Phosphate Glass as a Phosphate Source in High Cell Density Escherichia coli Fermentations

Abstract

Polyphosphate glass (sodium hexametaphosphate, sodium polyphosphate, glassy) was identified and tested as a source of phosphate that supports growth of recombinant Escherichia coli to cell densities over 110 g dry wt/L. Polyphosphate glasses cost no more than sodium and potassium phosphates, are more soluble than any other inorganic phosphate source, and do not form metallophosphate precipitates when mixed with other nutrients in proportions found in fermentation medias. Using a typical fermentation medium, 40% higher cell densities were obtained using polyphosphate glass rather than orthophosphate. Polyphosphate glasses will allow more flexibility in designing and executing high cell density fermentations.

Fermentation strategies for recombinant protein expression in the methylotrophic yeastPichia pastoris

“…It is recommended that PTM1 solutions be stored at room temperature to prevent biotin crystallization. The above medium (BSM+0.435% PTM1) will show some cloudiness when the pH is adjusted to 5.0, due to the very low solubility of orthophosphate (HPO 4 2-) with Mg 2+ , Ca 2+ , and the other polyvalent cations present in PTM1 trace metals [35]. This slight precipitation is acceptable and will disappear with cell growth.…”

Maximization of recombinantHelicobacter pylorineutrophil activating protein production inEscherichia coli: improvement of a chemically defined medium using response surface methodology

“…In fermentation perspective, usage of polyphosphate exhibits marked advantages viz. polyphosphate costs no more than sodium or potassium orthophosphate, is more soluble than any other inorganic phosphate source, and does not form metallo‐phosphate precipitates when mixed with other nutrients in proportions found in fermentation media [12].…”

Optimization of Culture Medium for Large-Scale Production of Heterologous Proteins in Pichia pastoris to be used in Nanoscience and other Biotechnological Fields

“…The proposed MBSM offers some advantages over its BSM counterpart because not only solves the imbalance problems of some atom-elements of the culture media previously reported [5,9], but also it is less expensive (accounting near $2 per liter, depending, of course, on supplier) and it is easy to prepare (it is not necessary a defined order to add the components nor adjust pH before to finish the addition of components of the culture medium) compared to BSM and other existing culture media used for P. pastoris, at large-scale protein production purposes. Besides, MBSM as shown in Table 3, can be useful for both P. pastoris developed promoters and scales, lab research studies and also suitable for large-scale production of recombinant proteins in biopharmaceutical, food, nanoscience, and chemical industries.…”

“…By far, the most common medium for high cell density fermentation of methylotrophic yeast Pichia pastoris is the basalt salt medium BSM proposed by Invitrogen Co. However, as reported by other researches [5,9], some problems during its preparation and sterilization arise due to component imbalances.…”

“…Despite the success accumulated by BSM use, this media presents some problems easily observed during its preparation and sterilizing procedures by the presence of a white-turbidity formation before inoculation, especially where pH ≥ 5 [8]. This turbidity is ascribed to the low solubility of the polyvalent cations calcium (Ca 2+ ) and magnesium (Mg 2+ ) present in the supplement PTM1, in the presence of ortho-phosphate anions (HPO 4 2-) [9]. Despite that this precipitation matter tends to disappear during the cultivation time, clearly leads to certain nutrient imbalance problems, especially if the medium pH increases above pH 5 [8].…”