Production of savinase and population viability of Bacillus clausii during high-cell-density fed-batch cultivations

Torben Christiansen, S. Michaelsen, M. Wumpelmann, Jens Nielsen

    Research output: Contribution to journal › Journal article › Research › peer-review

    Abstract

    The growth and product formation of a Savinase-producing Bacillus clausii were investigated in high-cell-density fed-batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for all feed profiles applied and, in addition, there was a time-dependent decrease in specific productivity. The specific glucose uptake rate increased with time for constant specific growth rate indicating that the maintenance requirements increased with time, possibly due to a decreasing K+ concentration. The physiological state of the cells was monitored during the cultivations using a flow cytometry assay based on the permeability of the cell membrane to propidium iodide. In the latter parts of the fed-batch cultures with a linear feed profile, a large portion of the cell population was found to have a permeable membrane, indicating a large percentage of dead cells. By assuming that only cells with a nonpermeable membrane contributed to growth and product formation, the physiological properties of this subpopulation were calculated.
    Original languageEnglish
    JournalBiotechnology and Bioengineering
    Volume83
    Issue number3
    Pages (from-to)344-352
    ISSN0006-3592
    Publication statusPublished - 2003

    Cite this

    Christiansen, Torben ; Michaelsen, S. ; Wumpelmann, M. ; Nielsen, Jens. / Production of savinase and population viability of Bacillus clausii during high-cell-density fed-batch cultivations. In: Biotechnology and Bioengineering. 2003 ; Vol. 83, No. 3. pp. 344-352.
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    abstract = "The growth and product formation of a Savinase-producing Bacillus clausii were investigated in high-cell-density fed-batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for all feed profiles applied and, in addition, there was a time-dependent decrease in specific productivity. The specific glucose uptake rate increased with time for constant specific growth rate indicating that the maintenance requirements increased with time, possibly due to a decreasing K+ concentration. The physiological state of the cells was monitored during the cultivations using a flow cytometry assay based on the permeability of the cell membrane to propidium iodide. In the latter parts of the fed-batch cultures with a linear feed profile, a large portion of the cell population was found to have a permeable membrane, indicating a large percentage of dead cells. By assuming that only cells with a nonpermeable membrane contributed to growth and product formation, the physiological properties of this subpopulation were calculated.",
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    Christiansen, T, Michaelsen, S, Wumpelmann, M & Nielsen, J 2003, 'Production of savinase and population viability of Bacillus clausii during high-cell-density fed-batch cultivations', Biotechnology and Bioengineering, vol. 83, no. 3, pp. 344-352.

    Production of savinase and population viability of Bacillus clausii during high-cell-density fed-batch cultivations. / Christiansen, Torben; Michaelsen, S.; Wumpelmann, M.; Nielsen, Jens.

    In: Biotechnology and Bioengineering, Vol. 83, No. 3, 2003, p. 344-352.

    Research output: Contribution to journal › Journal article › Research › peer-review

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    AU - Michaelsen, S.

    AU - Wumpelmann, M.

    AU - Nielsen, Jens

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    N2 - The growth and product formation of a Savinase-producing Bacillus clausii were investigated in high-cell-density fed-batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for all feed profiles applied and, in addition, there was a time-dependent decrease in specific productivity. The specific glucose uptake rate increased with time for constant specific growth rate indicating that the maintenance requirements increased with time, possibly due to a decreasing K+ concentration. The physiological state of the cells was monitored during the cultivations using a flow cytometry assay based on the permeability of the cell membrane to propidium iodide. In the latter parts of the fed-batch cultures with a linear feed profile, a large portion of the cell population was found to have a permeable membrane, indicating a large percentage of dead cells. By assuming that only cells with a nonpermeable membrane contributed to growth and product formation, the physiological properties of this subpopulation were calculated.

    AB - The growth and product formation of a Savinase-producing Bacillus clausii were investigated in high-cell-density fed-batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for all feed profiles applied and, in addition, there was a time-dependent decrease in specific productivity. The specific glucose uptake rate increased with time for constant specific growth rate indicating that the maintenance requirements increased with time, possibly due to a decreasing K+ concentration. The physiological state of the cells was monitored during the cultivations using a flow cytometry assay based on the permeability of the cell membrane to propidium iodide. In the latter parts of the fed-batch cultures with a linear feed profile, a large portion of the cell population was found to have a permeable membrane, indicating a large percentage of dead cells. By assuming that only cells with a nonpermeable membrane contributed to growth and product formation, the physiological properties of this subpopulation were calculated.

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    Christiansen T, Michaelsen S, Wumpelmann M, Nielsen J. Production of savinase and population viability of Bacillus clausii during high-cell-density fed-batch cultivations. Biotechnology and Bioengineering. 2003;83(3):344-352.